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Inet4Address.javaAPI DocJava SE 5 API11745Fri Aug 26 14:57:08 BST 2005java.net

Inet4Address

public final class Inet4Address extends InetAddress
This class represents an Internet Protocol version 4 (IPv4) address. Defined by RFC 790: Assigned Numbers, RFC 1918: Address Allocation for Private Internets, and RFC 2365: Administratively Scoped IP Multicast

Textual representation of IP addresses

Textual representation of IPv4 address used as input to methods takes one of the following forms:
d.d.d.d
d.d.d
d.d
d

When four parts are specified, each is interpreted as a byte of data and assigned, from left to right, to the four bytes of an IPv4 address.

When a three part address is specified, the last part is interpreted as a 16-bit quantity and placed in the right most two bytes of the network address. This makes the three part address format convenient for specifying Class B net- work addresses as 128.net.host.

When a two part address is supplied, the last part is interpreted as a 24-bit quantity and placed in the right most three bytes of the network address. This makes the two part address format convenient for specifying Class A network addresses as net.host.

When only one part is given, the value is stored directly in the network address without any byte rearrangement.

For methods that return a textual representation as output value, the first form, i.e. a dotted-quad string, is used.

The Scope of a Multicast Address

Historically the IPv4 TTL field in the IP header has doubled as a multicast scope field: a TTL of 0 means node-local, 1 means link-local, up through 32 means site-local, up through 64 means region-local, up through 128 means continent-local, and up through 255 are global. However, the administrative scoping is preferred. Please refer to RFC 2365: Administratively Scoped IP Multicast

Fields Summary
static final int
INADDRSZ
private static final long
serialVersionUID
use serialVersionUID from InetAddress, but Inet4Address instance is always replaced by an InetAddress instance before being serialized
private static final int
loopback
Utility routine to check if the InetAddress is a loopback address.
Constructors Summary
Inet4Address()


    /*
     * Perform initializations.
     */
     
        init();
    
	super();
	hostName = null;
	address = 0;
	family = IPv4;
    
Inet4Address(String hostName, byte[] addr)

	this.hostName = hostName;
	this.family = IPv4;
	if (addr != null) {
	    if (addr.length == INADDRSZ) {
		address  = addr[3] & 0xFF;
		address |= ((addr[2] << 8) & 0xFF00);
		address |= ((addr[1] << 16) & 0xFF0000);
		address |= ((addr[0] << 24) & 0xFF000000);
	    } 
	} 
    
Inet4Address(String hostName, int address)

	this.hostName = hostName;
	this.family = IPv4;
	this.address = address;
    
Methods Summary
public booleanequals(java.lang.Object obj)
Compares this object against the specified object. The result is true if and only if the argument is not null and it represents the same IP address as this object.

Two instances of InetAddress represent the same IP address if the length of the byte arrays returned by getAddress is the same for both, and each of the array components is the same for the byte arrays.

param
obj the object to compare against.
return
true if the objects are the same; false otherwise.
see
java.net.InetAddress#getAddress()

 
	return (obj != null) && (obj instanceof Inet4Address) &&
	    (((InetAddress)obj).address == address);	
    
public byte[]getAddress()
Returns the raw IP address of this InetAddress object. The result is in network byte order: the highest order byte of the address is in getAddress()[0].

return
the raw IP address of this object.

	byte[] addr = new byte[INADDRSZ];

	addr[0] = (byte) ((address >>> 24) & 0xFF);
	addr[1] = (byte) ((address >>> 16) & 0xFF);
	addr[2] = (byte) ((address >>> 8) & 0xFF);
	addr[3] = (byte) (address & 0xFF);
	return addr;
    
public java.lang.StringgetHostAddress()
Returns the IP address string in textual presentation form.

return
the raw IP address in a string format.
since
JDK1.0.2

	return numericToTextFormat(getAddress());
    
public inthashCode()
Returns a hashcode for this IP address.

return
a hash code value for this IP address.

	return address;
    
private static native voidinit()
Perform class load-time initializations.

public booleanisAnyLocalAddress()
Utility routine to check if the InetAddress in a wildcard address.

return
a boolean indicating if the Inetaddress is a wildcard address.
since
1.4

	return address == 0;
    
public booleanisLinkLocalAddress()
Utility routine to check if the InetAddress is an link local address.

return
a boolean indicating if the InetAddress is a link local address; or false if address is not a link local unicast address.
since
1.4

	// link-local unicast in IPv4 (169.254.0.0/16)
	// defined in "Documenting Special Use IPv4 Address Blocks
	// that have been Registered with IANA" by Bill Manning
	// draft-manning-dsua-06.txt
	return (((address >>> 24) & 0xFF) == 169) 
	    && (((address >>> 16) & 0xFF) == 254);
    
public booleanisLoopbackAddress()

 /* 127.0.0.1 */
       
 	/* 127.x.x.x */
 	byte[] byteAddr = getAddress();
 	return byteAddr[0] == 127;
    
public booleanisMCGlobal()
Utility routine to check if the multicast address has global scope.

return
a boolean indicating if the address has is a multicast address of global scope, false if it is not of global scope or it is not a multicast address
since
1.4

	// 224.0.1.0 to 238.255.255.255
 	byte[] byteAddr = getAddress();
 	return ((byteAddr[0] & 0xff) >= 224 && (byteAddr[0] & 0xff) <= 238 ) &&
 	    !((byteAddr[0] & 0xff) == 224 && byteAddr[1] == 0 &&
 	      byteAddr[2] == 0);
    
public booleanisMCLinkLocal()
Utility routine to check if the multicast address has link scope.

return
a boolean indicating if the address has is a multicast address of link-local scope, false if it is not of link-local scope or it is not a multicast address
since
1.4

	// 224.0.0/24 prefix and ttl == 1
	return (((address >>> 24) & 0xFF) == 224) 
	    && (((address >>> 16) & 0xFF) == 0)
	    && (((address >>> 8) & 0xFF) == 0);
    
public booleanisMCNodeLocal()
Utility routine to check if the multicast address has node scope.

return
a boolean indicating if the address has is a multicast address of node-local scope, false if it is not of node-local scope or it is not a multicast address
since
1.4

	// unless ttl == 0
	return false;
    
public booleanisMCOrgLocal()
Utility routine to check if the multicast address has organization scope.

return
a boolean indicating if the address has is a multicast address of organization-local scope, false if it is not of organization-local scope or it is not a multicast address
since
1.4

	// 239.192 - 239.195
	return (((address >>> 24) & 0xFF) == 239) 
	    && (((address >>> 16) & 0xFF) >= 192)
	    && (((address >>> 16) & 0xFF) <= 195);
    
public booleanisMCSiteLocal()
Utility routine to check if the multicast address has site scope.

return
a boolean indicating if the address has is a multicast address of site-local scope, false if it is not of site-local scope or it is not a multicast address
since
1.4

	// 239.255/16 prefix or ttl < 32
	return (((address >>> 24) & 0xFF) == 239) 
	    && (((address >>> 16) & 0xFF) == 255);
    
public booleanisMulticastAddress()
Utility routine to check if the InetAddress is an IP multicast address. IP multicast address is a Class D address i.e first four bits of the address are 1110.

return
a boolean indicating if the InetAddress is an IP multicast address
since
JDK1.1

	return ((address & 0xf0000000) == 0xe0000000);
    
public booleanisSiteLocalAddress()
Utility routine to check if the InetAddress is a site local address.

return
a boolean indicating if the InetAddress is a site local address; or false if address is not a site local unicast address.
since
1.4

	// refer to RFC 1918
	// 10/8 prefix
	// 172.16/12 prefix
	// 192.168/16 prefix
	return (((address >>> 24) & 0xFF) == 10)
	    || ((((address >>> 24) & 0xFF) == 172) 
		&& (((address >>> 16) & 0xF0) == 16))
	    || ((((address >>> 24) & 0xFF) == 192) 
		&& (((address >>> 16) & 0xFF) == 168));
    
static java.lang.StringnumericToTextFormat(byte[] src)

	return (src[0] & 0xff) + "." + (src[1] & 0xff) + "." + (src[2] & 0xff) + "." + (src[3] & 0xff);
    
private java.lang.ObjectwriteReplace()
Replaces the object to be serialized with an InetAddress object.

return
the alternate object to be serialized.
throws
ObjectStreamException if a new object replacing this object could not be created

	// will replace the to be serialized 'this' object
	InetAddress inet = new InetAddress();
	inet.hostName = this.hostName;
	inet.address = this.address;

	/**
	 * Prior to 1.4 an InetAddress was created with a family
  	 * based on the platform AF_INET value (usually 2).
         * For compatibility reasons we must therefore write the
	 * the InetAddress with this family.
	 */
	inet.family = 2;

	return inet;