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*
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/*
* $Header: /cvs/glassfish/appserv-api/src/java/com/sun/appserv/management/util/misc/StringEscaper.java,v 1.2 2007/05/05 05:31:06 tcfujii Exp $
* $Revision: 1.2 $
* $Date: 2007/05/05 05:31:06 $
*/
package com.sun.appserv.management.util.misc;
import java.text.StringCharacterIterator;
/**
Escapes/unescapes strings
*/
public final class StringEscaper
{
static final public char BACKSLASH = '\\';
static final public char NEWLINE = '\n';
static final public char RETURN = '\r';
static final public char TAB = '\t';
static final public char SPACE = ' ';
static final public char ESCAPE_CHAR = BACKSLASH;
static final public char UNICODE_START = 'u';
final char mEscapeChar;
final char[] mCharsToEscape;
StringCharacterIterator mCharIter;
public
StringEscaper()
{
this( "\n\r\t" );
}
public
StringEscaper( String charsToEscape )
{
this( ESCAPE_CHAR, charsToEscape );
}
public
StringEscaper( char escapeChar, String charsToEscape )
{
mCharIter = null;
mEscapeChar = escapeChar;
mCharsToEscape = new char[ 1 + charsToEscape.length() ];
mCharsToEscape[ 0 ] = ESCAPE_CHAR;
final int length = charsToEscape.length();
for( int i = 0; i < length; ++i )
{
mCharsToEscape[ i + 1 ] = charsToEscape.charAt( i );
}
}
boolean
shouldEscape( final char c )
{
boolean shouldEscape = false;
for( int i = 0; i < mCharsToEscape.length; ++i )
{
if ( c == mCharsToEscape[ i ] )
{
shouldEscape = true;
break;
}
}
return( shouldEscape );
}
/*
Get an escape sequence for the character.
*/
String
getEscapeSequence( char c )
{
String sequence = null;
if ( c == mEscapeChar )
{
sequence = "" + mEscapeChar + mEscapeChar;
}
else if ( c == NEWLINE )
{
sequence = mEscapeChar + "n";
}
else if ( c == RETURN )
{
sequence = mEscapeChar + "r";
}
else if ( c == TAB )
{
sequence = mEscapeChar + "t";
}
else if ( c == SPACE )
{
sequence = mEscapeChar + "s";
}
else
{
final int numericValue = (int)c;
String valueString = "" + Integer.toHexString( numericValue );
// make sure it's 4 digits by prepending leading zeroes
while ( valueString.length() != 4 )
{
valueString = "0" + valueString;
}
// careful not to append char to char
sequence = mEscapeChar + (UNICODE_START + valueString);
}
return( sequence );
}
public String
escape( String s)
{
final StringBuffer buf = new StringBuffer();
final int length = s.length();
for( int i = 0; i < length; ++i )
{
final char c = s.charAt( i );
if ( shouldEscape( c ) )
{
buf.append( getEscapeSequence( c ) );
}
else
{
buf.append( c );
}
}
return( buf.toString() );
}
boolean
hasMoreChars()
{
return( mCharIter.current() != mCharIter.DONE );
}
char
peekNextChar()
{
return( mCharIter.current() );
}
char
nextChar()
{
final char theChar = mCharIter.current();
mCharIter.next();
if ( theChar == mCharIter.DONE )
{
throw new ArrayIndexOutOfBoundsException();
}
return( theChar );
}
char
escapeSequenceToChar()
{
final char c = nextChar();
char result = 0;
if ( c == mEscapeChar )
{
result = mEscapeChar;
}
else if ( c == 'n' )
{
result = NEWLINE;
}
else if ( c == 'r' )
{
result = RETURN;
}
else if ( c == 't' )
{
result = TAB;
}
else if ( c == 's' )
{
result = SPACE;
}
else if ( c == UNICODE_START )
{
final String unicodeSequence = "" + nextChar() + nextChar() + nextChar() + nextChar();
final int intValue = Integer.parseInt( unicodeSequence, 16 );
result = (char)intValue;
}
else
{
throw new IllegalArgumentException( "Illegal escape sequence" );
}
return( result );
}
public String
unescape( String s )
{
final StringBuffer buf = new StringBuffer();
mCharIter = new StringCharacterIterator( s );
while ( hasMoreChars() )
{
final char c = (char)nextChar();
assert ( c != mCharIter.DONE );
if ( c == mEscapeChar )
{
final char newChar = escapeSequenceToChar();
buf.append( newChar );
}
else
{
buf.append( c );
}
}
mCharIter = null;
return( buf.toString() );
}
}
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