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URI.javaAPI DocJava SE 6 API119169Tue Jun 10 00:25:42 BST 2008java.net

URI

public final class URI extends Object implements Comparable, Serializable
Represents a Uniform Resource Identifier (URI) reference.

Aside from some minor deviations noted below, an instance of this class represents a URI reference as defined by RFC 2396: Uniform Resource Identifiers (URI): Generic Syntax, amended by RFC 2732: Format for Literal IPv6 Addresses in URLs. The Literal IPv6 address format also supports scope_ids. The syntax and usage of scope_ids is described here. This class provides constructors for creating URI instances from their components or by parsing their string forms, methods for accessing the various components of an instance, and methods for normalizing, resolving, and relativizing URI instances. Instances of this class are immutable.

URI syntax and components

At the highest level a URI reference (hereinafter simply "URI") in string form has the syntax
[scheme:]scheme-specific-part[#fragment]
where square brackets [...] delineate optional components and the characters : and # stand for themselves.

An absolute URI specifies a scheme; a URI that is not absolute is said to be relative. URIs are also classified according to whether they are opaque or hierarchical.

An opaque URI is an absolute URI whose scheme-specific part does not begin with a slash character ('/'). Opaque URIs are not subject to further parsing. Some examples of opaque URIs are:

mailto:java-net@java.sun.com
news:comp.lang.java
urn:isbn:096139210x

A hierarchical URI is either an absolute URI whose scheme-specific part begins with a slash character, or a relative URI, that is, a URI that does not specify a scheme. Some examples of hierarchical URIs are:

http://java.sun.com/j2se/1.3/
docs/guide/collections/designfaq.html#28
../../../demo/jfc/SwingSet2/src/SwingSet2.java
file:///~/calendar

A hierarchical URI is subject to further parsing according to the syntax

[scheme:][//authority][path][?query][#fragment]
where the characters :, /, ?, and # stand for themselves. The scheme-specific part of a hierarchical URI consists of the characters between the scheme and fragment components.

The authority component of a hierarchical URI is, if specified, either server-based or registry-based. A server-based authority parses according to the familiar syntax

[user-info@]host[:port]
where the characters @ and : stand for themselves. Nearly all URI schemes currently in use are server-based. An authority component that does not parse in this way is considered to be registry-based.

The path component of a hierarchical URI is itself said to be absolute if it begins with a slash character ('/'); otherwise it is relative. The path of a hierarchical URI that is either absolute or specifies an authority is always absolute.

All told, then, a URI instance has the following nine components:

ComponentType
schemeString
scheme-specific-part    String
authorityString
user-infoString
hostString
portint
pathString
queryString
fragmentString
In a given instance any particular component is either undefined or defined with a distinct value. Undefined string components are represented by null, while undefined integer components are represented by -1. A string component may be defined to have the empty string as its value; this is not equivalent to that component being undefined.

Whether a particular component is or is not defined in an instance depends upon the type of the URI being represented. An absolute URI has a scheme component. An opaque URI has a scheme, a scheme-specific part, and possibly a fragment, but has no other components. A hierarchical URI always has a path (though it may be empty) and a scheme-specific-part (which at least contains the path), and may have any of the other components. If the authority component is present and is server-based then the host component will be defined and the user-information and port components may be defined.

Operations on URI instances

The key operations supported by this class are those of normalization, resolution, and relativization.

Normalization is the process of removing unnecessary "." and ".." segments from the path component of a hierarchical URI. Each "." segment is simply removed. A ".." segment is removed only if it is preceded by a non-".." segment. Normalization has no effect upon opaque URIs.

Resolution is the process of resolving one URI against another, base URI. The resulting URI is constructed from components of both URIs in the manner specified by RFC 2396, taking components from the base URI for those not specified in the original. For hierarchical URIs, the path of the original is resolved against the path of the base and then normalized. The result, for example, of resolving

docs/guide/collections/designfaq.html#28          (1)
against the base URI http://java.sun.com/j2se/1.3/ is the result URI
http://java.sun.com/j2se/1.3/docs/guide/collections/designfaq.html#28
Resolving the relative URI
../../../demo/jfc/SwingSet2/src/SwingSet2.java    (2)
against this result yields, in turn,
http://java.sun.com/j2se/1.3/demo/jfc/SwingSet2/src/SwingSet2.java
Resolution of both absolute and relative URIs, and of both absolute and relative paths in the case of hierarchical URIs, is supported. Resolving the URI file:///~calendar against any other URI simply yields the original URI, since it is absolute. Resolving the relative URI (2) above against the relative base URI (1) yields the normalized, but still relative, URI
demo/jfc/SwingSet2/src/SwingSet2.java

Relativization, finally, is the inverse of resolution: For any two normalized URIs u and v,

u.relativize(u.resolve(v)).equals(v)  and
u.resolve(u.relativize(v)).equals(v)  .
This operation is often useful when constructing a document containing URIs that must be made relative to the base URI of the document wherever possible. For example, relativizing the URI
http://java.sun.com/j2se/1.3/docs/guide/index.html
against the base URI
http://java.sun.com/j2se/1.3
yields the relative URI docs/guide/index.html.

Character categories

RFC 2396 specifies precisely which characters are permitted in the various components of a URI reference. The following categories, most of which are taken from that specification, are used below to describe these constraints:
alpha The US-ASCII alphabetic characters, 'A' through 'Z' and 'a' through 'z'
digit The US-ASCII decimal digit characters, '0' through '9'
alphanum All alpha and digit characters
unreserved     All alphanum characters together with those in the string "_-!.~'()*"
punct The characters in the string ",;:$&+="
reserved All punct characters together with those in the string "?/[]@"
escaped Escaped octets, that is, triplets consisting of the percent character ('%') followed by two hexadecimal digits ('0'-'9', 'A'-'F', and 'a'-'f')
other The Unicode characters that are not in the US-ASCII character set, are not control characters (according to the {@link java.lang.Character#isISOControl(char) Character.isISOControl} method), and are not space characters (according to the {@link java.lang.Character#isSpaceChar(char) Character.isSpaceChar} method)  (Deviation from RFC 2396, which is limited to US-ASCII)

The set of all legal URI characters consists of the unreserved, reserved, escaped, and other characters.

Escaped octets, quotation, encoding, and decoding

RFC 2396 allows escaped octets to appear in the user-info, path, query, and fragment components. Escaping serves two purposes in URIs:
  • To encode non-US-ASCII characters when a URI is required to conform strictly to RFC 2396 by not containing any other characters.

  • To quote characters that are otherwise illegal in a component. The user-info, path, query, and fragment components differ slightly in terms of which characters are considered legal and illegal.

These purposes are served in this class by three related operations:
  • A character is encoded by replacing it with the sequence of escaped octets that represent that character in the UTF-8 character set. The Euro currency symbol ('\u20AC'), for example, is encoded as "%E2%82%AC". (Deviation from RFC 2396, which does not specify any particular character set.)

  • An illegal character is quoted simply by encoding it. The space character, for example, is quoted by replacing it with "%20". UTF-8 contains US-ASCII, hence for US-ASCII characters this transformation has exactly the effect required by RFC 2396.

  • A sequence of escaped octets is decoded by replacing it with the sequence of characters that it represents in the UTF-8 character set. UTF-8 contains US-ASCII, hence decoding has the effect of de-quoting any quoted US-ASCII characters as well as that of decoding any encoded non-US-ASCII characters. If a decoding error occurs when decoding the escaped octets then the erroneous octets are replaced by '\uFFFD', the Unicode replacement character.

These operations are exposed in the constructors and methods of this class as follows:
  • The {@link #URI(java.lang.String) single-argument constructor} requires any illegal characters in its argument to be quoted and preserves any escaped octets and other characters that are present.

  • The {@link #URI(java.lang.String,java.lang.String,java.lang.String,int,java.lang.String,java.lang.String,java.lang.String) multi-argument constructors} quote illegal characters as required by the components in which they appear. The percent character ('%') is always quoted by these constructors. Any other characters are preserved.

  • The {@link #getRawUserInfo() getRawUserInfo}, {@link #getRawPath() getRawPath}, {@link #getRawQuery() getRawQuery}, {@link #getRawFragment() getRawFragment}, {@link #getRawAuthority() getRawAuthority}, and {@link #getRawSchemeSpecificPart() getRawSchemeSpecificPart} methods return the values of their corresponding components in raw form, without interpreting any escaped octets. The strings returned by these methods may contain both escaped octets and other characters, and will not contain any illegal characters.

  • The {@link #getUserInfo() getUserInfo}, {@link #getPath() getPath}, {@link #getQuery() getQuery}, {@link #getFragment() getFragment}, {@link #getAuthority() getAuthority}, and {@link #getSchemeSpecificPart() getSchemeSpecificPart} methods decode any escaped octets in their corresponding components. The strings returned by these methods may contain both other characters and illegal characters, and will not contain any escaped octets.

  • The {@link #toString() toString} method returns a URI string with all necessary quotation but which may contain other characters.

  • The {@link #toASCIIString() toASCIIString} method returns a fully quoted and encoded URI string that does not contain any other characters.

Identities

For any URI u, it is always the case that
new URI(u.toString()).equals(u) .
For any URI u that does not contain redundant syntax such as two slashes before an empty authority (as in file:///tmp/ ) or a colon following a host name but no port (as in http://java.sun.com: ), and that does not encode characters except those that must be quoted, the following identities also hold:
new URI(u.getScheme(),
        
u.getSchemeSpecificPart(),
        
u.getFragment())
.equals(
u)
in all cases,
new URI(u.getScheme(),
        
u.getUserInfo(), u.getAuthority(),
        
u.getPath(), u.getQuery(),
        
u.getFragment())
.equals(
u)
if u is hierarchical, and
new URI(u.getScheme(),
        
u.getUserInfo(), u.getHost(), u.getPort(),
        
u.getPath(), u.getQuery(),
        
u.getFragment())
.equals(
u)
if u is hierarchical and has either no authority or a server-based authority.

URIs, URLs, and URNs

A URI is a uniform resource identifier while a URL is a uniform resource locator. Hence every URL is a URI, abstractly speaking, but not every URI is a URL. This is because there is another subcategory of URIs, uniform resource names (URNs), which name resources but do not specify how to locate them. The mailto, news, and isbn URIs shown above are examples of URNs.

The conceptual distinction between URIs and URLs is reflected in the differences between this class and the {@link URL} class.

An instance of this class represents a URI reference in the syntactic sense defined by RFC 2396. A URI may be either absolute or relative. A URI string is parsed according to the generic syntax without regard to the scheme, if any, that it specifies. No lookup of the host, if any, is performed, and no scheme-dependent stream handler is constructed. Equality, hashing, and comparison are defined strictly in terms of the character content of the instance. In other words, a URI instance is little more than a structured string that supports the syntactic, scheme-independent operations of comparison, normalization, resolution, and relativization.

An instance of the {@link URL} class, by contrast, represents the syntactic components of a URL together with some of the information required to access the resource that it describes. A URL must be absolute, that is, it must always specify a scheme. A URL string is parsed according to its scheme. A stream handler is always established for a URL, and in fact it is impossible to create a URL instance for a scheme for which no handler is available. Equality and hashing depend upon both the scheme and the Internet address of the host, if any; comparison is not defined. In other words, a URL is a structured string that supports the syntactic operation of resolution as well as the network I/O operations of looking up the host and opening a connection to the specified resource.

version
1.48, 06/06/12
author
Mark Reinhold
since
1.4
see
RFC 2279: UTF-8, a transformation format of ISO 10646,
RFC 2373: IPv6 Addressing Architecture,
RFC 2396: Uniform Resource Identifiers (URI): Generic Syntax,
RFC 2732: Format for Literal IPv6 Addresses in URLs,
URISyntaxException

Fields Summary
static final long
serialVersionUID
private transient String
scheme
private transient String
fragment
private transient String
authority
private transient String
userInfo
private transient String
host
private transient int
port
private transient String
path
private transient String
query
private volatile transient String
schemeSpecificPart
private volatile transient int
hash
private volatile transient String
decodedUserInfo
private volatile transient String
decodedAuthority
private volatile transient String
decodedPath
private volatile transient String
decodedQuery
private volatile transient String
decodedFragment
private volatile transient String
decodedSchemeSpecificPart
private volatile String
string
The string form of this URI.
private static final long
L_DIGIT
private static final long
H_DIGIT
private static final long
L_UPALPHA
private static final long
H_UPALPHA
private static final long
L_LOWALPHA
private static final long
H_LOWALPHA
private static final long
L_ALPHA
private static final long
H_ALPHA
private static final long
L_ALPHANUM
private static final long
H_ALPHANUM
private static final long
L_HEX
private static final long
H_HEX
private static final long
L_MARK
private static final long
H_MARK
private static final long
L_UNRESERVED
private static final long
H_UNRESERVED
private static final long
L_RESERVED
private static final long
H_RESERVED
private static final long
L_ESCAPED
private static final long
H_ESCAPED
private static final long
L_URIC
private static final long
H_URIC
private static final long
L_PCHAR
private static final long
H_PCHAR
private static final long
L_PATH
private static final long
H_PATH
private static final long
L_DASH
private static final long
H_DASH
private static final long
L_DOT
private static final long
H_DOT
private static final long
L_USERINFO
private static final long
H_USERINFO
private static final long
L_REG_NAME
private static final long
H_REG_NAME
private static final long
L_SERVER
private static final long
H_SERVER
private static final long
L_SERVER_PERCENT
private static final long
H_SERVER_PERCENT
private static final long
L_LEFT_BRACKET
private static final long
H_LEFT_BRACKET
private static final long
L_SCHEME
private static final long
H_SCHEME
private static final long
L_URIC_NO_SLASH
private static final long
H_URIC_NO_SLASH
private static final char[]
hexDigits
Constructors Summary
private URI()

		// The only serializable field



    // -- Constructors and factories --

       
public URI(String str)
Constructs a URI by parsing the given string.

This constructor parses the given string exactly as specified by the grammar in RFC 2396, Appendix A, except for the following deviations:

  • An empty authority component is permitted as long as it is followed by a non-empty path, a query component, or a fragment component. This allows the parsing of URIs such as "file:///foo/bar", which seems to be the intent of RFC 2396 although the grammar does not permit it. If the authority component is empty then the user-information, host, and port components are undefined.

  • Empty relative paths are permitted; this seems to be the intent of RFC 2396 although the grammar does not permit it. The primary consequence of this deviation is that a standalone fragment such as "#foo" parses as a relative URI with an empty path and the given fragment, and can be usefully resolved against a base URI.

  • IPv4 addresses in host components are parsed rigorously, as specified by RFC 2732: Each element of a dotted-quad address must contain no more than three decimal digits. Each element is further constrained to have a value no greater than 255.

  • Hostnames in host components that comprise only a single domain label are permitted to start with an alphanum character. This seems to be the intent of RFC 2396 section 3.2.2 although the grammar does not permit it. The consequence of this deviation is that the authority component of a hierarchical URI such as s://123, will parse as a server-based authority.

  • IPv6 addresses are permitted for the host component. An IPv6 address must be enclosed in square brackets ('[' and ']') as specified by RFC 2732. The IPv6 address itself must parse according to RFC 2373. IPv6 addresses are further constrained to describe no more than sixteen bytes of address information, a constraint implicit in RFC 2373 but not expressible in the grammar.

  • Characters in the other category are permitted wherever RFC 2396 permits escaped octets, that is, in the user-information, path, query, and fragment components, as well as in the authority component if the authority is registry-based. This allows URIs to contain Unicode characters beyond those in the US-ASCII character set.

param
str The string to be parsed into a URI
throws
NullPointerException If str is null
throws
URISyntaxException If the given string violates RFC 2396, as augmented by the above deviations

	new Parser(str).parse(false);
    
public URI(String scheme, String userInfo, String host, int port, String path, String query, String fragment)
Constructs a hierarchical URI from the given components.

If a scheme is given then the path, if also given, must either be empty or begin with a slash character ('/'). Otherwise a component of the new URI may be left undefined by passing null for the corresponding parameter or, in the case of the port parameter, by passing -1.

This constructor first builds a URI string from the given components according to the rules specified in RFC 2396, section 5.2, step 7:

  1. Initially, the result string is empty.

  2. If a scheme is given then it is appended to the result, followed by a colon character (':').

  3. If user information, a host, or a port are given then the string "//" is appended.

  4. If user information is given then it is appended, followed by a commercial-at character ('@'). Any character not in the unreserved, punct, escaped, or other categories is quoted.

  5. If a host is given then it is appended. If the host is a literal IPv6 address but is not enclosed in square brackets ('[' and ']') then the square brackets are added.

  6. If a port number is given then a colon character (':') is appended, followed by the port number in decimal.

  7. If a path is given then it is appended. Any character not in the unreserved, punct, escaped, or other categories, and not equal to the slash character ('/') or the commercial-at character ('@'), is quoted.

  8. If a query is given then a question-mark character ('?') is appended, followed by the query. Any character that is not a legal URI character is quoted.

  9. Finally, if a fragment is given then a hash character ('#') is appended, followed by the fragment. Any character that is not a legal URI character is quoted.

The resulting URI string is then parsed as if by invoking the {@link #URI(String)} constructor and then invoking the {@link #parseServerAuthority()} method upon the result; this may cause a {@link URISyntaxException} to be thrown.

param
scheme Scheme name
param
userInfo User name and authorization information
param
host Host name
param
port Port number
param
path Path
param
query Query
param
fragment Fragment
throws
URISyntaxException If both a scheme and a path are given but the path is relative, if the URI string constructed from the given components violates RFC 2396, or if the authority component of the string is present but cannot be parsed as a server-based authority

	String s = toString(scheme, null,
			    null, userInfo, host, port,
			    path, query, fragment);
	checkPath(s, scheme, path);
	new Parser(s).parse(true);
    
public URI(String scheme, String authority, String path, String query, String fragment)
Constructs a hierarchical URI from the given components.

If a scheme is given then the path, if also given, must either be empty or begin with a slash character ('/'). Otherwise a component of the new URI may be left undefined by passing null for the corresponding parameter.

This constructor first builds a URI string from the given components according to the rules specified in RFC 2396, section 5.2, step 7:

  1. Initially, the result string is empty.

  2. If a scheme is given then it is appended to the result, followed by a colon character (':').

  3. If an authority is given then the string "//" is appended, followed by the authority. If the authority contains a literal IPv6 address then the address must be enclosed in square brackets ('[' and ']'). Any character not in the unreserved, punct, escaped, or other categories, and not equal to the commercial-at character ('@'), is quoted.

  4. If a path is given then it is appended. Any character not in the unreserved, punct, escaped, or other categories, and not equal to the slash character ('/') or the commercial-at character ('@'), is quoted.

  5. If a query is given then a question-mark character ('?') is appended, followed by the query. Any character that is not a legal URI character is quoted.

  6. Finally, if a fragment is given then a hash character ('#') is appended, followed by the fragment. Any character that is not a legal URI character is quoted.

The resulting URI string is then parsed as if by invoking the {@link #URI(String)} constructor and then invoking the {@link #parseServerAuthority()} method upon the result; this may cause a {@link URISyntaxException} to be thrown.

param
scheme Scheme name
param
authority Authority
param
path Path
param
query Query
param
fragment Fragment
throws
URISyntaxException If both a scheme and a path are given but the path is relative, if the URI string constructed from the given components violates RFC 2396, or if the authority component of the string is present but cannot be parsed as a server-based authority

	String s = toString(scheme, null,
			    authority, null, null, -1,
			    path, query, fragment);
	checkPath(s, scheme, path);
	new Parser(s).parse(false);
    
public URI(String scheme, String host, String path, String fragment)
Constructs a hierarchical URI from the given components.

A component may be left undefined by passing null.

This convenience constructor works as if by invoking the seven-argument constructor as follows:

new {@link #URI(String, String, String, int, String, String, String) URI}(scheme, null, host, -1, path, null, fragment);

param
scheme Scheme name
param
host Host name
param
path Path
param
fragment Fragment
throws
URISyntaxException If the URI string constructed from the given components violates RFC 2396

	this(scheme, null, host, -1, path, null, fragment);
    
public URI(String scheme, String ssp, String fragment)
Constructs a URI from the given components.

A component may be left undefined by passing null.

This constructor first builds a URI in string form using the given components as follows:

  1. Initially, the result string is empty.

  2. If a scheme is given then it is appended to the result, followed by a colon character (':').

  3. If a scheme-specific part is given then it is appended. Any character that is not a legal URI character is quoted.

  4. Finally, if a fragment is given then a hash character ('#') is appended to the string, followed by the fragment. Any character that is not a legal URI character is quoted.

The resulting URI string is then parsed in order to create the new URI instance as if by invoking the {@link #URI(String)} constructor; this may cause a {@link URISyntaxException} to be thrown.

param
scheme Scheme name
param
ssp Scheme-specific part
param
fragment Fragment
throws
URISyntaxException If the URI string constructed from the given components violates RFC 2396

	new Parser(toString(scheme, ssp,
			    null, null, null, -1,
			    null, null, fragment))
	    .parse(false);
    
Methods Summary
private voidappendAuthority(java.lang.StringBuffer sb, java.lang.String authority, java.lang.String userInfo, java.lang.String host, int port)

	if (host != null) {
	    sb.append("//");
	    if (userInfo != null) {
		sb.append(quote(userInfo, L_USERINFO, H_USERINFO));
		sb.append('@");
	    }
	    boolean needBrackets = ((host.indexOf(':") >= 0)
				    && !host.startsWith("[")
				    && !host.endsWith("]"));
	    if (needBrackets) sb.append('[");
	    sb.append(host);
	    if (needBrackets) sb.append(']");
	    if (port != -1) {
		sb.append(':");
		sb.append(port);
	    }
	} else if (authority != null) {
	    sb.append("//");
	    if (authority.startsWith("[")) {
		int end = authority.indexOf("]");
		if (end != -1 && authority.indexOf(":")!=-1) {
		    String doquote, dontquote;
		    if (end == authority.length()) {
			dontquote = authority;
			doquote = "";
		    } else {
		    	dontquote = authority.substring(0,end+1);
			doquote = authority.substring(end+1);
		    }
		    sb.append (dontquote);
	    	    sb.append(quote(doquote, 
			    L_REG_NAME | L_SERVER,
			    H_REG_NAME | H_SERVER));
		}
	    } else {
	    	sb.append(quote(authority,
			    L_REG_NAME | L_SERVER,
			    H_REG_NAME | H_SERVER));
	    }
	}
    
private static voidappendEncoded(java.lang.StringBuffer sb, char c)

	ByteBuffer bb = null;
	try {
	    bb = ThreadLocalCoders.encoderFor("UTF-8")
		.encode(CharBuffer.wrap("" + c));
	} catch (CharacterCodingException x) {
	    assert false;
	}
	while (bb.hasRemaining()) {
	    int b = bb.get() & 0xff;
	    if (b >= 0x80)
		appendEscape(sb, (byte)b);
	    else
		sb.append((char)b);
	}
    
private static voidappendEscape(java.lang.StringBuffer sb, byte b)


           
	sb.append('%");
	sb.append(hexDigits[(b >> 4) & 0x0f]);
	sb.append(hexDigits[(b >> 0) & 0x0f]);
    
private voidappendFragment(java.lang.StringBuffer sb, java.lang.String fragment)

	if (fragment != null) {
	    sb.append('#");
	    sb.append(quote(fragment, L_URIC, H_URIC));
	}
    
private voidappendSchemeSpecificPart(java.lang.StringBuffer sb, java.lang.String opaquePart, java.lang.String authority, java.lang.String userInfo, java.lang.String host, int port, java.lang.String path, java.lang.String query)

	if (opaquePart != null) {
	    /* check if SSP begins with an IPv6 address
	     * because we must not quote a literal IPv6 address
	     */
	    if (opaquePart.startsWith("//[")) {
		int end =  opaquePart.indexOf("]");
		if (end != -1 && opaquePart.indexOf(":")!=-1) {
		    String doquote, dontquote;
		    if (end == opaquePart.length()) {
			dontquote = opaquePart;
			doquote = "";
		    } else {
		    	dontquote = opaquePart.substring(0,end+1);
			doquote = opaquePart.substring(end+1);
		    }
		    sb.append (dontquote);
	    	    sb.append(quote(doquote, L_URIC, H_URIC));
		}
	    } else {
	    	sb.append(quote(opaquePart, L_URIC, H_URIC));
	    }
	} else {
	    appendAuthority(sb, authority, userInfo, host, port);
	    if (path != null) 
		sb.append(quote(path, L_PATH, H_PATH));
	    if (query != null) {
		sb.append('?");
		sb.append(quote(query, L_URIC, H_URIC));
	    }
	}
    
private static voidcheckPath(java.lang.String s, java.lang.String scheme, java.lang.String path)

	if (scheme != null) {
	    if ((path != null)
		&& ((path.length() > 0) && (path.charAt(0) != '/")))
		throw new URISyntaxException(s,
					     "Relative path in absolute URI");
	}
    
private static intcompare(java.lang.String s, java.lang.String t)

	if (s == t) return 0;
	if (s != null) {
	    if (t != null)
		return s.compareTo(t);
	    else
		return +1;
	} else {
	    return -1;
	}
    
private static intcompareIgnoringCase(java.lang.String s, java.lang.String t)

	if (s == t) return 0;
	if (s != null) {
	    if (t != null) {
		int sn = s.length();
		int tn = t.length();
		int n = sn < tn ? sn : tn;
		for (int i = 0; i < n; i++) {
		    int c = toLower(s.charAt(i)) - toLower(t.charAt(i));
		    if (c != 0)
			return c;
		}
		return sn - tn;
	    }
	    return +1;
	} else {
	    return -1;
	}
    
public intcompareTo(java.net.URI that)
Compares this URI to another object, which must be a URI.

When comparing corresponding components of two URIs, if one component is undefined but the other is defined then the first is considered to be less than the second. Unless otherwise noted, string components are ordered according to their natural, case-sensitive ordering as defined by the {@link java.lang.String#compareTo(Object) String.compareTo} method. String components that are subject to encoding are compared by comparing their raw forms rather than their encoded forms.

The ordering of URIs is defined as follows:

  • Two URIs with different schemes are ordered according the ordering of their schemes, without regard to case.

  • A hierarchical URI is considered to be less than an opaque URI with an identical scheme.

  • Two opaque URIs with identical schemes are ordered according to the ordering of their scheme-specific parts.

  • Two opaque URIs with identical schemes and scheme-specific parts are ordered according to the ordering of their fragments.

  • Two hierarchical URIs with identical schemes are ordered according to the ordering of their authority components:

    • If both authority components are server-based then the URIs are ordered according to their user-information components; if these components are identical then the URIs are ordered according to the ordering of their hosts, without regard to case; if the hosts are identical then the URIs are ordered according to the ordering of their ports.

    • If one or both authority components are registry-based then the URIs are ordered according to the ordering of their authority components.

  • Finally, two hierarchical URIs with identical schemes and authority components are ordered according to the ordering of their paths; if their paths are identical then they are ordered according to the ordering of their queries; if the queries are identical then they are ordered according to the order of their fragments.

This method satisfies the general contract of the {@link java.lang.Comparable#compareTo(Object) Comparable.compareTo} method.

param
that The object to which this URI is to be compared
return
A negative integer, zero, or a positive integer as this URI is less than, equal to, or greater than the given URI
throws
ClassCastException If the given object is not a URI

	int c;

	if ((c = compareIgnoringCase(this.scheme, that.scheme)) != 0)
	    return c;

	if (this.isOpaque()) {
	    if (that.isOpaque()) {
		// Both opaque
		if ((c = compare(this.schemeSpecificPart,
				 that.schemeSpecificPart)) != 0)
		    return c;
		return compare(this.fragment, that.fragment);
	    }
	    return +1;			// Opaque > hierarchical
	} else if (that.isOpaque()) {
	    return -1;			// Hierarchical < opaque
	}

	// Hierarchical
	if ((this.host != null) && (that.host != null)) {
	    // Both server-based
	    if ((c = compare(this.userInfo, that.userInfo)) != 0)
		return c;
	    if ((c = compareIgnoringCase(this.host, that.host)) != 0)
		return c;
	    if ((c = this.port - that.port) != 0)
		return c;
	} else {
	    // If one or both authorities are registry-based then we simply
	    // compare them in the usual, case-sensitive way.  If one is
	    // registry-based and one is server-based then the strings are
	    // guaranteed to be unequal, hence the comparison will never return
	    // zero and the compareTo and equals methods will remain
	    // consistent.
	    if ((c = compare(this.authority, that.authority)) != 0) return c;
	}

	if ((c = compare(this.path, that.path)) != 0) return c;
	if ((c = compare(this.query, that.query)) != 0) return c;
	return compare(this.fragment, that.fragment);
    
public static java.net.URIcreate(java.lang.String str)
Creates a URI by parsing the given string.

This convenience factory method works as if by invoking the {@link #URI(String)} constructor; any {@link URISyntaxException} thrown by the constructor is caught and wrapped in a new {@link IllegalArgumentException} object, which is then thrown.

This method is provided for use in situations where it is known that the given string is a legal URI, for example for URI constants declared within in a program, and so it would be considered a programming error for the string not to parse as such. The constructors, which throw {@link URISyntaxException} directly, should be used situations where a URI is being constructed from user input or from some other source that may be prone to errors.

param
str The string to be parsed into a URI
return
The new URI
throws
NullPointerException If str is null
throws
IllegalArgumentException If the given string violates RFC 2396

	try {
	    return new URI(str);
	} catch (URISyntaxException x) {
	    IllegalArgumentException y = new IllegalArgumentException();
	    y.initCause(x);
	    throw y;
	}
    
private static intdecode(char c)

	if ((c >= '0") && (c <= '9"))
	    return c - '0";
	if ((c >= 'a") && (c <= 'f"))
	    return c - 'a" + 10;
	if ((c >= 'A") && (c <= 'F"))
	    return c - 'A" + 10;
	assert false;
	return -1;
    
private static bytedecode(char c1, char c2)

	return (byte)(  ((decode(c1) & 0xf) << 4)
		      | ((decode(c2) & 0xf) << 0));
    
private static java.lang.Stringdecode(java.lang.String s)

	if (s == null)
	    return s;
	int n = s.length();
	if (n == 0)
	    return s;
	if (s.indexOf('%") < 0)
	    return s;

	byte[] ba = new byte[n];
	StringBuffer sb = new StringBuffer(n);
	ByteBuffer bb = ByteBuffer.allocate(n);
	CharBuffer cb = CharBuffer.allocate(n);
	CharsetDecoder dec = ThreadLocalCoders.decoderFor("UTF-8")
	    .onMalformedInput(CodingErrorAction.REPLACE)
	    .onUnmappableCharacter(CodingErrorAction.REPLACE);

	// This is not horribly efficient, but it will do for now
	char c = s.charAt(0);
    	boolean betweenBrackets = false;

	for (int i = 0; i < n;) {
	    assert c == s.charAt(i);	// Loop invariant
	    if (c == '[") {
		betweenBrackets = true;
	    } else if (betweenBrackets && c == ']") {
		betweenBrackets = false;
	    }
	    if (c != '%" || betweenBrackets) {
		sb.append(c);
		if (++i >= n)
		    break;
		c = s.charAt(i);
		continue;
	    }
	    bb.clear();
	    int ui = i;
	    for (;;) {
		assert (n - i >= 2);
		bb.put(decode(s.charAt(++i), s.charAt(++i)));
		if (++i >= n)
		    break;
		c = s.charAt(i);
		if (c != '%")
		    break;
	    }
	    bb.flip();
	    cb.clear();
	    dec.reset();
	    CoderResult cr = dec.decode(bb, cb, true);
	    assert cr.isUnderflow();
	    cr = dec.flush(cb);
	    assert cr.isUnderflow();
	    sb.append(cb.flip().toString());
	}

	return sb.toString();
    
private voiddefineSchemeSpecificPart()

	if (schemeSpecificPart != null) return;
	StringBuffer sb = new StringBuffer();
	appendSchemeSpecificPart(sb, null, getAuthority(), getUserInfo(),
				 host, port, getPath(), getQuery());
	if (sb.length() == 0) return;
	schemeSpecificPart = sb.toString();
    
private voiddefineString()

	if (string != null) return;

	StringBuffer sb = new StringBuffer();
        if (scheme != null) {
            sb.append(scheme);
            sb.append(':");
        }
	if (isOpaque()) {
            sb.append(schemeSpecificPart);
        } else {
	    if (host != null) {
                sb.append("//");
                if (userInfo != null) {
                    sb.append(userInfo);
                    sb.append('@");
                }
                boolean needBrackets = ((host.indexOf(':") >= 0)
                                    && !host.startsWith("[")
                                    && !host.endsWith("]"));
                if (needBrackets) sb.append('[");
                sb.append(host);
                if (needBrackets) sb.append(']");
                if (port != -1) {
                    sb.append(':");
                    sb.append(port);
                }
            } else if (authority != null) {
                sb.append("//");
                sb.append(authority);
	    }
            if (path != null)
                sb.append(path);
            if (query != null) {
                sb.append('?");
                sb.append(query);
            }
        }
	if (fragment != null) {
            sb.append('#");
            sb.append(fragment);
	}
	string = sb.toString();
    
private static java.lang.Stringencode(java.lang.String s)

	int n = s.length();
	if (n == 0)
	    return s;

	// First check whether we actually need to encode
	for (int i = 0;;) {
	    if (s.charAt(i) >= '\u0080")
		break;
	    if (++i >= n)
		return s;
	}

	String ns = Normalizer.normalize(s, Normalizer.Form.NFC);
	ByteBuffer bb = null;
	try {
	    bb = ThreadLocalCoders.encoderFor("UTF-8")
		.encode(CharBuffer.wrap(ns));
	} catch (CharacterCodingException x) {
	    assert false;
	}

	StringBuffer sb = new StringBuffer();
	while (bb.hasRemaining()) {
	    int b = bb.get() & 0xff;
	    if (b >= 0x80)
		appendEscape(sb, (byte)b);
	    else
		sb.append((char)b);
	}
	return sb.toString();
    
private static booleanequal(java.lang.String s, java.lang.String t)

	if (s == t) return true;
	if ((s != null) && (t != null)) {
	    if (s.length() != t.length())
		return false;
	    if (s.indexOf('%") < 0)
		return s.equals(t);
	    int n = s.length();
	    for (int i = 0; i < n;) {
		char c = s.charAt(i);
		char d = t.charAt(i);
		if (c != '%") {
		    if (c != d)
			return false;
		    i++;
		    continue;
		}
		i++;
		if (toLower(s.charAt(i)) != toLower(t.charAt(i)))
		    return false;
		i++;
		if (toLower(s.charAt(i)) != toLower(t.charAt(i)))
		    return false;
		i++;
	    }
	    return true;
	}
	return false;
    
private static booleanequalIgnoringCase(java.lang.String s, java.lang.String t)

	if (s == t) return true;
	if ((s != null) && (t != null)) {
	    int n = s.length();
	    if (t.length() != n)
		return false;
	    for (int i = 0; i < n; i++) {
		if (toLower(s.charAt(i)) != toLower(t.charAt(i)))
		    return false;
	    }
	    return true;
	}
	return false;
    
public booleanequals(java.lang.Object ob)
Tests this URI for equality with another object.

If the given object is not a URI then this method immediately returns false.

For two URIs to be considered equal requires that either both are opaque or both are hierarchical. Their schemes must either both be undefined or else be equal without regard to case. Their fragments must either both be undefined or else be equal.

For two opaque URIs to be considered equal, their scheme-specific parts must be equal.

For two hierarchical URIs to be considered equal, their paths must be equal and their queries must either both be undefined or else be equal. Their authorities must either both be undefined, or both be registry-based, or both be server-based. If their authorities are defined and are registry-based, then they must be equal. If their authorities are defined and are server-based, then their hosts must be equal without regard to case, their port numbers must be equal, and their user-information components must be equal.

When testing the user-information, path, query, fragment, authority, or scheme-specific parts of two URIs for equality, the raw forms rather than the encoded forms of these components are compared and the hexadecimal digits of escaped octets are compared without regard to case.

This method satisfies the general contract of the {@link java.lang.Object#equals(Object) Object.equals} method.

param
ob The object to which this object is to be compared
return
true if, and only if, the given object is a URI that is identical to this URI

	if (ob == this)
	    return true;
	if (!(ob instanceof URI))
	    return false;
	URI that = (URI)ob;
	if (this.isOpaque() != that.isOpaque()) return false;
	if (!equalIgnoringCase(this.scheme, that.scheme)) return false;
	if (!equal(this.fragment, that.fragment)) return false;

	// Opaque
	if (this.isOpaque())
	    return equal(this.schemeSpecificPart, that.schemeSpecificPart);

	// Hierarchical
	if (!equal(this.path, that.path)) return false;
	if (!equal(this.query, that.query)) return false;

	// Authorities
	if (this.authority == that.authority) return true;
	if (this.host != null) {
	    // Server-based
	    if (!equal(this.userInfo, that.userInfo)) return false;
	    if (!equalIgnoringCase(this.host, that.host)) return false;
	    if (this.port != that.port) return false;
	} else if (this.authority != null) {
	    // Registry-based
	    if (!equal(this.authority, that.authority)) return false;
	} else if (this.authority != that.authority) {
	    return false;
	}

	return true;
    
public java.lang.StringgetAuthority()
Returns the decoded authority component of this URI.

The string returned by this method is equal to that returned by the {@link #getRawAuthority() getRawAuthority} method except that all sequences of escaped octets are decoded.

return
The decoded authority component of this URI, or null if the authority is undefined

	if (decodedAuthority == null)
	    decodedAuthority = decode(authority);
	return decodedAuthority;
    
public java.lang.StringgetFragment()
Returns the decoded fragment component of this URI.

The string returned by this method is equal to that returned by the {@link #getRawFragment() getRawFragment} method except that all sequences of escaped octets are decoded.

return
The decoded fragment component of this URI, or null if the fragment is undefined

	if ((decodedFragment == null) && (fragment != null))
	    decodedFragment = decode(fragment);
	return decodedFragment;
    
public java.lang.StringgetHost()
Returns the host component of this URI.

The host component of a URI, if defined, will have one of the following forms:

  • A domain name consisting of one or more labels separated by period characters ('.'), optionally followed by a period character. Each label consists of alphanum characters as well as hyphen characters ('-'), though hyphens never occur as the first or last characters in a label. The rightmost label of a domain name consisting of two or more labels, begins with an alpha character.

  • A dotted-quad IPv4 address of the form digit+.digit+.digit+.digit+, where no digit sequence is longer than three characters and no sequence has a value larger than 255.

  • An IPv6 address enclosed in square brackets ('[' and ']') and consisting of hexadecimal digits, colon characters (':'), and possibly an embedded IPv4 address. The full syntax of IPv6 addresses is specified in RFC 2373: IPv6 Addressing Architecture.

The host component of a URI cannot contain escaped octets, hence this method does not perform any decoding.

return
The host component of this URI, or null if the host is undefined

	return host;
    
public java.lang.StringgetPath()
Returns the decoded path component of this URI.

The string returned by this method is equal to that returned by the {@link #getRawPath() getRawPath} method except that all sequences of escaped octets are decoded.

return
The decoded path component of this URI, or null if the path is undefined

	if ((decodedPath == null) && (path != null))
	    decodedPath = decode(path);
	return decodedPath;
    
public intgetPort()
Returns the port number of this URI.

The port component of a URI, if defined, is a non-negative integer.

return
The port component of this URI, or -1 if the port is undefined

	return port;
    
public java.lang.StringgetQuery()
Returns the decoded query component of this URI.

The string returned by this method is equal to that returned by the {@link #getRawQuery() getRawQuery} method except that all sequences of escaped octets are decoded.

return
The decoded query component of this URI, or null if the query is undefined

	if ((decodedQuery == null) && (query != null))
	    decodedQuery = decode(query);
	return decodedQuery;
    
public java.lang.StringgetRawAuthority()
Returns the raw authority component of this URI.

The authority component of a URI, if defined, only contains the commercial-at character ('@') and characters in the unreserved, punct, escaped, and other categories. If the authority is server-based then it is further constrained to have valid user-information, host, and port components.

return
The raw authority component of this URI, or null if the authority is undefined

	return authority;
    
public java.lang.StringgetRawFragment()
Returns the raw fragment component of this URI.

The fragment component of a URI, if defined, only contains legal URI characters.

return
The raw fragment component of this URI, or null if the fragment is undefined

	return fragment;
    
public java.lang.StringgetRawPath()
Returns the raw path component of this URI.

The path component of a URI, if defined, only contains the slash character ('/'), the commercial-at character ('@'), and characters in the unreserved, punct, escaped, and other categories.

return
The path component of this URI, or null if the path is undefined

	return path;
    
public java.lang.StringgetRawQuery()
Returns the raw query component of this URI.

The query component of a URI, if defined, only contains legal URI characters.

return
The raw query component of this URI, or null if the query is undefined

	return query;
    
public java.lang.StringgetRawSchemeSpecificPart()
Returns the raw scheme-specific part of this URI. The scheme-specific part is never undefined, though it may be empty.

The scheme-specific part of a URI only contains legal URI characters.

return
The raw scheme-specific part of this URI (never null)

	defineSchemeSpecificPart();
	return schemeSpecificPart;
    
public java.lang.StringgetRawUserInfo()
Returns the raw user-information component of this URI.

The user-information component of a URI, if defined, only contains characters in the unreserved, punct, escaped, and other categories.

return
The raw user-information component of this URI, or null if the user information is undefined

	return userInfo;
    
public java.lang.StringgetScheme()
Returns the scheme component of this URI.

The scheme component of a URI, if defined, only contains characters in the alphanum category and in the string "-.+". A scheme always starts with an alpha character.

The scheme component of a URI cannot contain escaped octets, hence this method does not perform any decoding.

return
The scheme component of this URI, or null if the scheme is undefined

	return scheme;
    
public java.lang.StringgetSchemeSpecificPart()
Returns the decoded scheme-specific part of this URI.

The string returned by this method is equal to that returned by the {@link #getRawSchemeSpecificPart() getRawSchemeSpecificPart} method except that all sequences of escaped octets are decoded.

return
The decoded scheme-specific part of this URI (never null)

	if (decodedSchemeSpecificPart == null)
	    decodedSchemeSpecificPart = decode(getRawSchemeSpecificPart());
	return decodedSchemeSpecificPart;
    
public java.lang.StringgetUserInfo()
Returns the decoded user-information component of this URI.

The string returned by this method is equal to that returned by the {@link #getRawUserInfo() getRawUserInfo} method except that all sequences of escaped octets are decoded.

return
The decoded user-information component of this URI, or null if the user information is undefined

	if ((decodedUserInfo == null) && (userInfo != null))
	    decodedUserInfo = decode(userInfo);
	return decodedUserInfo;
    
private static inthash(int hash, java.lang.String s)

	if (s == null) return hash;
	return hash * 127 + s.hashCode();
    
public inthashCode()
Returns a hash-code value for this URI. The hash code is based upon all of the URI's components, and satisfies the general contract of the {@link java.lang.Object#hashCode() Object.hashCode} method.

return
A hash-code value for this URI

	if (hash != 0)
	    return hash;
	int h = hashIgnoringCase(0, scheme);
	h = hash(h, fragment);
	if (isOpaque()) {
	    h = hash(h, schemeSpecificPart);
	} else {
	    h = hash(h, path);
	    h = hash(h, query);
	    if (host != null) {
		h = hash(h, userInfo);
		h = hashIgnoringCase(h, host);
		h += 1949 * port;
	    } else {
		h = hash(h, authority);
	    }
	}
	hash = h;
	return h;
    
private static inthashIgnoringCase(int hash, java.lang.String s)

	if (s == null) return hash;
	int h = hash;
	int n = s.length();
	for (int i = 0; i < n; i++)
	    h = 31 * h + toLower(s.charAt(i));
	return h;
    
private static longhighMask(java.lang.String chars)

	int n = chars.length();
	long m = 0;
	for (int i = 0; i < n; i++) {
	    char c = chars.charAt(i);
	    if ((c >= 64) && (c < 128))
		m |= (1L << (c - 64));
	}
	return m;
    
private static longhighMask(char first, char last)

	long m = 0;
	int f = Math.max(Math.min(first, 127), 64) - 64;
	int l = Math.max(Math.min(last, 127), 64) - 64;
	for (int i = f; i <= l; i++)
	    m |= 1L << i;
	return m;
    
public booleanisAbsolute()
Tells whether or not this URI is absolute.

A URI is absolute if, and only if, it has a scheme component.

return
true if, and only if, this URI is absolute

	return scheme != null;
    
public booleanisOpaque()
Tells whether or not this URI is opaque.

A URI is opaque if, and only if, it is absolute and its scheme-specific part does not begin with a slash character ('/'). An opaque URI has a scheme, a scheme-specific part, and possibly a fragment; all other components are undefined.

return
true if, and only if, this URI is opaque

        return path == null;
    
private static intjoin(char[] path, int[] segs)

	int ns = segs.length;		// Number of segments
	int end = path.length - 1;	// Index of last char in path
	int p = 0;			// Index of next path char to write

	if (path[p] == '\0") {
	    // Restore initial slash for absolute paths
	    path[p++] = '/";
	}

	for (int i = 0; i < ns; i++) {
	    int q = segs[i];		// Current segment
	    if (q == -1)
		// Ignore this segment
		continue;

	    if (p == q) {
		// We're already at this segment, so just skip to its end
		while ((p <= end) && (path[p] != '\0"))
		    p++;
		if (p <= end) {
		    // Preserve trailing slash
		    path[p++] = '/";
		}
	    } else if (p < q) {
		// Copy q down to p
		while ((q <= end) && (path[q] != '\0"))
		    path[p++] = path[q++];
		if (q <= end) {
		    // Preserve trailing slash
		    path[p++] = '/";
		}
	    } else
		throw new InternalError(); // ASSERT false
	}

	return p;
    
private static longlowMask(java.lang.String chars)

	int n = chars.length();
	long m = 0;
	for (int i = 0; i < n; i++) {
	    char c = chars.charAt(i);
	    if (c < 64)
		m |= (1L << c);
	}
	return m;
    
private static longlowMask(char first, char last)

	long m = 0;
	int f = Math.max(Math.min(first, 63), 0);
	int l = Math.max(Math.min(last, 63), 0);
	for (int i = f; i <= l; i++)
	    m |= 1L << i;
	return m;
    
private static booleanmatch(char c, long lowMask, long highMask)

	if (c < 64)
	    return ((1L << c) & lowMask) != 0;
	if (c < 128)
	    return ((1L << (c - 64)) & highMask) != 0;
	return false;
    
private static voidmaybeAddLeadingDot(char[] path, int[] segs)


	if (path[0] == '\0")
	    // The path is absolute
	    return;

	int ns = segs.length;
	int f = 0;			// Index of first segment
	while (f < ns) {
	    if (segs[f] >= 0)
		break;
	    f++;
	}
	if ((f >= ns) || (f == 0))
	    // The path is empty, or else the original first segment survived,
	    // in which case we already know that no leading "." is needed
	    return;

	int p = segs[f];
	while ((p < path.length) && (path[p] != ':") && (path[p] != '\0")) p++;
	if (p >= path.length || path[p] == '\0")
	    // No colon in first segment, so no "." needed
	    return;

	// At this point we know that the first segment is unused,
	// hence we can insert a "." segment at that position
	path[0] = '.";
	path[1] = '\0";
	segs[0] = 0;
    
private static intneedsNormalization(java.lang.String path)

	boolean normal = true;
	int ns = 0;			// Number of segments
	int end = path.length() - 1;	// Index of last char in path
	int p = 0;			// Index of next char in path

	// Skip initial slashes
	while (p <= end) {
	    if (path.charAt(p) != '/") break;
	    p++;
	}
	if (p > 1) normal = false;

	// Scan segments
	while (p <= end) {

	    // Looking at "." or ".." ?
	    if ((path.charAt(p) == '.")
		&& ((p == end)
		    || ((path.charAt(p + 1) == '/")
			|| ((path.charAt(p + 1) == '.")
			    && ((p + 1 == end)
				|| (path.charAt(p + 2) == '/")))))) {
		normal = false;
	    }
	    ns++;

	    // Find beginning of next segment
	    while (p <= end) {
		if (path.charAt(p++) != '/")
		    continue;

		// Skip redundant slashes
		while (p <= end) {
		    if (path.charAt(p) != '/") break;
		    normal = false;
		    p++;
		}

		break;
	    }
	}

	return normal ? -1 : ns;
    
private static java.net.URInormalize(java.net.URI u)

	if (u.isOpaque() || (u.path == null) || (u.path.length() == 0))
	    return u;

	String np = normalize(u.path);
	if (np == u.path)
	    return u;

	URI v = new URI();
	v.scheme = u.scheme;
	v.fragment = u.fragment;
	v.authority = u.authority;
	v.userInfo = u.userInfo;
	v.host = u.host;
	v.port = u.port;
	v.path = np;
	v.query = u.query;
	return v;
    
private static java.lang.Stringnormalize(java.lang.String ps)


	// Does this path need normalization?
	int ns = needsNormalization(ps);	// Number of segments
	if (ns < 0)
	    // Nope -- just return it
	    return ps;

	char[] path = ps.toCharArray();		// Path in char-array form

	// Split path into segments
	int[] segs = new int[ns];		// Segment-index array
	split(path, segs);

	// Remove dots
	removeDots(path, segs);

	// Prevent scheme-name confusion
	maybeAddLeadingDot(path, segs);

	// Join the remaining segments and return the result
	String s = new String(path, 0, join(path, segs));
	if (s.equals(ps)) {
	    // string was already normalized
	    return ps;
	}
	return s;
    
public java.net.URInormalize()
Normalizes this URI's path.

If this URI is opaque, or if its path is already in normal form, then this URI is returned. Otherwise a new URI is constructed that is identical to this URI except that its path is computed by normalizing this URI's path in a manner consistent with RFC 2396, section 5.2, step 6, sub-steps c through f; that is:

  1. All "." segments are removed.

  2. If a ".." segment is preceded by a non-".." segment then both of these segments are removed. This step is repeated until it is no longer applicable.

  3. If the path is relative, and if its first segment contains a colon character (':'), then a "." segment is prepended. This prevents a relative URI with a path such as "a:b/c/d" from later being re-parsed as an opaque URI with a scheme of "a" and a scheme-specific part of "b/c/d". (Deviation from RFC 2396)

A normalized path will begin with one or more ".." segments if there were insufficient non-".." segments preceding them to allow their removal. A normalized path will begin with a "." segment if one was inserted by step 3 above. Otherwise, a normalized path will not contain any "." or ".." segments.

return
A URI equivalent to this URI, but whose path is in normal form

	return normalize(this);
    
public java.net.URIparseServerAuthority()
Attempts to parse this URI's authority component, if defined, into user-information, host, and port components.

If this URI's authority component has already been recognized as being server-based then it will already have been parsed into user-information, host, and port components. In this case, or if this URI has no authority component, this method simply returns this URI.

Otherwise this method attempts once more to parse the authority component into user-information, host, and port components, and throws an exception describing why the authority component could not be parsed in that way.

This method is provided because the generic URI syntax specified in RFC 2396 cannot always distinguish a malformed server-based authority from a legitimate registry-based authority. It must therefore treat some instances of the former as instances of the latter. The authority component in the URI string "//foo:bar", for example, is not a legal server-based authority but it is legal as a registry-based authority.

In many common situations, for example when working URIs that are known to be either URNs or URLs, the hierarchical URIs being used will always be server-based. They therefore must either be parsed as such or treated as an error. In these cases a statement such as

URI u = new URI(str).parseServerAuthority();

can be used to ensure that u always refers to a URI that, if it has an authority component, has a server-based authority with proper user-information, host, and port components. Invoking this method also ensures that if the authority could not be parsed in that way then an appropriate diagnostic message can be issued based upon the exception that is thrown.

return
A URI whose authority field has been parsed as a server-based authority
throws
URISyntaxException If the authority component of this URI is defined but cannot be parsed as a server-based authority according to RFC 2396

	// We could be clever and cache the error message and index from the
	// exception thrown during the original parse, but that would require
	// either more fields or a more-obscure representation.
	if ((host != null) || (authority == null))
	    return this;
	defineString();
	new Parser(string).parse(true);
	return this;
    
private static java.lang.Stringquote(java.lang.String s, long lowMask, long highMask)

	int n = s.length();
	StringBuffer sb = null;
	boolean allowNonASCII = ((lowMask & L_ESCAPED) != 0);
	for (int i = 0; i < s.length(); i++) {
	    char c = s.charAt(i);
	    if (c < '\u0080") {
		if (!match(c, lowMask, highMask)) {
		    if (sb == null) {
			sb = new StringBuffer();
			sb.append(s.substring(0, i));
		    }
		    appendEscape(sb, (byte)c);
		} else {
		    if (sb != null)
			sb.append(c);
		}
	    } else if (allowNonASCII
		       && (Character.isSpaceChar(c)
			   || Character.isISOControl(c))) {
		if (sb == null) {
		    sb = new StringBuffer();
		    sb.append(s.substring(0, i));
		}
		appendEncoded(sb, c);
	    } else {
		if (sb != null)
		    sb.append(c);
	    }
	}
	return (sb == null) ? s : sb.toString();
    
private voidreadObject(java.io.ObjectInputStream is)
Reconstitutes a URI from the given serial stream.

The {@link java.io.ObjectInputStream#defaultReadObject()} method is invoked to read the value of the string field. The result is then parsed in the usual way.

param
is The object-input stream from which this object is being read

	port = -1;			// Argh
	is.defaultReadObject();
	try {
	    new Parser(string).parse(false);
	} catch (URISyntaxException x) {
	    IOException y = new InvalidObjectException("Invalid URI");
	    y.initCause(x);
	    throw y;
	}
    
public java.net.URIrelativize(java.net.URI uri)
Relativizes the given URI against this URI.

The relativization of the given URI against this URI is computed as follows:

  1. If either this URI or the given URI are opaque, or if the scheme and authority components of the two URIs are not identical, or if the path of this URI is not a prefix of the path of the given URI, then the given URI is returned.

  2. Otherwise a new relative hierarchical URI is constructed with query and fragment components taken from the given URI and with a path component computed by removing this URI's path from the beginning of the given URI's path.

param
uri The URI to be relativized against this URI
return
The resulting URI
throws
NullPointerException If uri is null

	return relativize(this, uri);
    
private static java.net.URIrelativize(java.net.URI base, java.net.URI child)

	// check if child if opaque first so that NPE is thrown 
        // if child is null.
	if (child.isOpaque() || base.isOpaque())
	    return child;
	if (!equalIgnoringCase(base.scheme, child.scheme)
	    || !equal(base.authority, child.authority))
	    return child;

	String bp = normalize(base.path);
	String cp = normalize(child.path);
	if (!bp.equals(cp)) {
	    if (!bp.endsWith("/"))
		bp = bp + "/";
	    if (!cp.startsWith(bp))
		return child;
	}

	URI v = new URI();
	v.path = cp.substring(bp.length());
	v.query = child.query;
	v.fragment = child.fragment;
	return v;
    
private static voidremoveDots(char[] path, int[] segs)

	int ns = segs.length;
	int end = path.length - 1;

	for (int i = 0; i < ns; i++) {
	    int dots = 0;		// Number of dots found (0, 1, or 2)

	    // Find next occurrence of "." or ".."
	    do {
		int p = segs[i];
		if (path[p] == '.") {
		    if (p == end) {
			dots = 1;
			break;
		    } else if (path[p + 1] == '\0") {
			dots = 1;
			break;
		    } else if ((path[p + 1] == '.")
			       && ((p + 1 == end)
				   || (path[p + 2] == '\0"))) {
			dots = 2;
			break;
		    }
		}
		i++;
	    } while (i < ns);
	    if ((i > ns) || (dots == 0))
		break;

	    if (dots == 1) {
		// Remove this occurrence of "."
		segs[i] = -1;
	    } else {
		// If there is a preceding non-".." segment, remove both that
		// segment and this occurrence of ".."; otherwise, leave this
		// ".." segment as-is.
		int j;
		for (j = i - 1; j >= 0; j--) {
		    if (segs[j] != -1) break;
		}
		if (j >= 0) {
		    int q = segs[j];
		    if (!((path[q] == '.")
			  && (path[q + 1] == '.")
			  && (path[q + 2] == '\0"))) {
			segs[i] = -1;
			segs[j] = -1;
		    }
		}
	    }
	}
    
public java.net.URIresolve(java.net.URI uri)
Resolves the given URI against this URI.

If the given URI is already absolute, or if this URI is opaque, then the given URI is returned.

If the given URI's fragment component is defined, its path component is empty, and its scheme, authority, and query components are undefined, then a URI with the given fragment but with all other components equal to those of this URI is returned. This allows a URI representing a standalone fragment reference, such as "#foo", to be usefully resolved against a base URI.

Otherwise this method constructs a new hierarchical URI in a manner consistent with RFC 2396, section 5.2; that is:

  1. A new URI is constructed with this URI's scheme and the given URI's query and fragment components.

  2. If the given URI has an authority component then the new URI's authority and path are taken from the given URI.

  3. Otherwise the new URI's authority component is copied from this URI, and its path is computed as follows:

    1. If the given URI's path is absolute then the new URI's path is taken from the given URI.

    2. Otherwise the given URI's path is relative, and so the new URI's path is computed by resolving the path of the given URI against the path of this URI. This is done by concatenating all but the last segment of this URI's path, if any, with the given URI's path and then normalizing the result as if by invoking the {@link #normalize() normalize} method.

The result of this method is absolute if, and only if, either this URI is absolute or the given URI is absolute.

param
uri The URI to be resolved against this URI
return
The resulting URI
throws
NullPointerException If uri is null

	return resolve(this, uri);
    
public java.net.URIresolve(java.lang.String str)
Constructs a new URI by parsing the given string and then resolving it against this URI.

This convenience method works as if invoking it were equivalent to evaluating the expression {@link #resolve(java.net.URI) resolve}(URI.{@link #create(String) create}(str)).

param
str The string to be parsed into a URI
return
The resulting URI
throws
NullPointerException If str is null
throws
IllegalArgumentException If the given string violates RFC 2396

	return resolve(URI.create(str));
    
private static java.net.URIresolve(java.net.URI base, java.net.URI child)

	// check if child if opaque first so that NPE is thrown 
	// if child is null.
	if (child.isOpaque() || base.isOpaque())
	    return child;

	// 5.2 (2): Reference to current document (lone fragment)
	if ((child.scheme == null) && (child.authority == null)
	    && child.path.equals("") && (child.fragment != null)
	    && (child.query == null)) {
	    if ((base.fragment != null)
		&& child.fragment.equals(base.fragment)) {
		return base;
	    }
	    URI ru = new URI();
	    ru.scheme = base.scheme;
	    ru.authority = base.authority;
	    ru.userInfo = base.userInfo;
	    ru.host = base.host;
	    ru.port = base.port;
	    ru.path = base.path;
	    ru.fragment = child.fragment;
	    ru.query = base.query;
	    return ru;
	}

	// 5.2 (3): Child is absolute
	if (child.scheme != null)
	    return child;

	URI ru = new URI();		// Resolved URI
	ru.scheme = base.scheme;
	ru.query = child.query;
	ru.fragment = child.fragment;

	// 5.2 (4): Authority
	if (child.authority == null) {
	    ru.authority = base.authority;
	    ru.host = base.host;
	    ru.userInfo = base.userInfo;
	    ru.port = base.port;

	    String cp = (child.path == null) ? "" : child.path;
	    if ((cp.length() > 0) && (cp.charAt(0) == '/")) {
		// 5.2 (5): Child path is absolute
		ru.path = child.path;
	    } else {
		// 5.2 (6): Resolve relative path
		ru.path = resolvePath(base.path, cp, base.isAbsolute());
	    }
	} else {
	    ru.authority = child.authority;
	    ru.host = child.host;
	    ru.userInfo = child.userInfo;
	    ru.host = child.host;
	    ru.port = child.port;
	    ru.path = child.path;
	}

	// 5.2 (7): Recombine (nothing to do here)
	return ru;
    
private static java.lang.StringresolvePath(java.lang.String base, java.lang.String child, boolean absolute)

        int i = base.lastIndexOf('/");
	int cn = child.length();
	String path = "";

	if (cn == 0) {
	    // 5.2 (6a)
	    if (i >= 0)
		path = base.substring(0, i + 1);
	} else {
	    StringBuffer sb = new StringBuffer(base.length() + cn);
	    // 5.2 (6a)
	    if (i >= 0)
		sb.append(base.substring(0, i + 1));
	    // 5.2 (6b)
	    sb.append(child);
	    path = sb.toString();
	}

	// 5.2 (6c-f)
	String np = normalize(path);

	// 5.2 (6g): If the result is absolute but the path begins with "../",
	// then we simply leave the path as-is

	return np;
    
private static voidsplit(char[] path, int[] segs)

	int end = path.length - 1;	// Index of last char in path
	int p = 0;			// Index of next char in path
	int i = 0;			// Index of current segment

	// Skip initial slashes
	while (p <= end) {
	    if (path[p] != '/") break;
	    path[p] = '\0";
	    p++;
	}

	while (p <= end) {

	    // Note start of segment
	    segs[i++] = p++;

	    // Find beginning of next segment
	    while (p <= end) {
		if (path[p++] != '/")
		    continue;
		path[p - 1] = '\0";

		// Skip redundant slashes
		while (p <= end) {
		    if (path[p] != '/") break;
		    path[p++] = '\0";
		}
		break;
	    }
	}

	if (i != segs.length)
	    throw new InternalError();	// ASSERT
    
public java.lang.StringtoASCIIString()
Returns the content of this URI as a US-ASCII string.

If this URI does not contain any characters in the other category then an invocation of this method will return the same value as an invocation of the {@link #toString() toString} method. Otherwise this method works as if by invoking that method and then encoding the result.

return
The string form of this URI, encoded as needed so that it only contains characters in the US-ASCII charset

	defineString();
	return encode(string);
    
private static inttoLower(char c)

	if ((c >= 'A") && (c <= 'Z"))
	    return c + ('a" - 'A");
	return c;
    
public java.lang.StringtoString()
Returns the content of this URI as a string.

If this URI was created by invoking one of the constructors in this class then a string equivalent to the original input string, or to the string computed from the originally-given components, as appropriate, is returned. Otherwise this URI was created by normalization, resolution, or relativization, and so a string is constructed from this URI's components according to the rules specified in RFC 2396, section 5.2, step 7.

return
The string form of this URI

	defineString();
	return string;
    
private java.lang.StringtoString(java.lang.String scheme, java.lang.String opaquePart, java.lang.String authority, java.lang.String userInfo, java.lang.String host, int port, java.lang.String path, java.lang.String query, java.lang.String fragment)

	StringBuffer sb = new StringBuffer();
	if (scheme != null) {
	    sb.append(scheme);
	    sb.append(':");
	}
	appendSchemeSpecificPart(sb, opaquePart,
				 authority, userInfo, host, port,
				 path, query);
	appendFragment(sb, fragment);
	return sb.toString();
    
public java.net.URLtoURL()
Constructs a URL from this URI.

This convenience method works as if invoking it were equivalent to evaluating the expression new URL(this.toString()) after first checking that this URI is absolute.

return
A URL constructed from this URI
throws
IllegalArgumentException If this URL is not absolute
throws
MalformedURLException If a protocol handler for the URL could not be found, or if some other error occurred while constructing the URL

	if (!isAbsolute())
	    throw new IllegalArgumentException("URI is not absolute");
	return new URL(toString());
    
private voidwriteObject(java.io.ObjectOutputStream os)
Saves the content of this URI to the given serial stream.

The only serializable field of a URI instance is its string field. That field is given a value, if it does not have one already, and then the {@link java.io.ObjectOutputStream#defaultWriteObject()} method of the given object-output stream is invoked.

param
os The object-output stream to which this object is to be written

	defineString();
	os.defaultWriteObject();	// Writes the string field only