gw.util.GosuEscapeUtil Maven / Gradle / Ivy
/*
* Copyright 2014 Guidewire Software, Inc.
*/
package gw.util;
public class GosuEscapeUtil
{
/**
* Escape any special characters in the string, using the Java escape syntax.
* For example any tabs become \t, newlines become \n etc.
*
* @return the escaped string. Returns the original string unchanged if it
* contains no special characters.
*/
public static String escapeForJava( String string )
{
String result;
StringBuffer resultBuffer = null;
for( int i = 0, length = string.length(); i < length; i++ )
{
char ch = string.charAt( i );
String escape = escapeForJava( ch );
if( escape != null )
{
if( resultBuffer == null )
{
resultBuffer = new StringBuffer( string );
resultBuffer.setLength( i );
}
resultBuffer.append( escape );
}
else if( resultBuffer != null )
{
resultBuffer.append( ch );
}
}
result = (resultBuffer != null) ? resultBuffer.toString() : string;
return result;
}
/**
* Converts an escaped character code into a string literal expressing it, e.g. '\n' becomes "\\n".
*
* @param ch Escaped character code.
*
* @return The string expression of the character code, null if ch is not an escaped character.
* Supports Unicode.
*/
public static String escapeForJava( char ch )
{
String escape = escapeForGosuStringLiteral( ch );
if( escape == null )
{
if( ch <= 31 || ch >= 127 )
{
escape = getUnicodeEscape( ch );
}
}
return escape;
}
public static String escapeForGosuStringLiteral( String strText )
{
return escapeForGosuStringLiteral( strText, 0, strText.length() );
}
public static String escapeForGosuStringLiteral( String strText, int iStart, int iEnd )
{
StringBuilder sb = new StringBuilder( strText.length() );
for( int i = iStart; i < iEnd; i++ )
{
sb.append( escapeForGosuStringLiteral( strText.charAt( i ) ) );
}
return sb.toString();
}
public static String escapeForGosuStringLiteral( char ch )
{
switch( ch )
{
case '\b':
return "\\b";
case '\f':
return "\\f";
case '\n':
return "\\n";
case '\r':
return "\\r";
case '\t':
return "\\t";
case '\'':
return "\\'";
case '\"':
return "\\\"";
case '\\':
return "\\\\";
default:
return isPrintableAscii( ch )
? String.valueOf( ch )
: String.format( "\\u%04x", (int)ch );
}
}
private static boolean isPrintableAscii( char ch )
{
return ch >= ' ' && ch <= '~';
}
public static String getUnicodeEscape( char ch )
{
String strPrefix = "\\u";
int iLen = strPrefix.length() + 4;
String strHexValue = Integer.toHexString( ch );
StringBuilder sb = new StringBuilder( iLen );
sb.append( strPrefix );
for( int i = 0, n = iLen - (strPrefix.length() + strHexValue.length()); i < n; i++ )
{
sb.append( '0' );
}
sb.append( strHexValue );
return sb.toString();
}
public static String stripNewLinesAndExtraneousWhiteSpace( String s )
{
if( s == null )
{
return null;
}
StringBuilder result = new StringBuilder();
boolean hitNewLine = false;
boolean addedSpace = false;
for( int i = 0; i < s.length(); i++ )
{
char c = s.charAt( i );
if( c == '\n' )
{
hitNewLine = true;
}
else if( c == ' ' )
{
if( hitNewLine )
{
if( !addedSpace )
{
result.append( c );
addedSpace = true;
}
}
else
{
result.append( c );
}
}
else
{
hitNewLine = false;
addedSpace = false;
result.append( c );
}
}
return result.toString().trim();
}
public static String escapeForHTML( String string )
{
return escapeForHTML( string, true );
}
public static String escapeForHTML( String string, boolean escapeWhitespace )
{
if( string == null || string.length() == 0 )
{
return string;
}
StringBuilder resultBuffer = null;
char last = 0;
for( int i = 0, length = string.length(); i < length; i++ )
{
String entity = null;
char ch = string.charAt( i );
switch( ch )
{
case '<':
{
entity = "<";
break;
}
case ' ':
if( last == ' ' && escapeWhitespace )
{
entity = " ";
}
break;
case '>':
entity = ">";
break;
case '&':
entity = "&";
break;
case '"':
entity = """;
break;
case '\n':
if( escapeWhitespace )
{
entity = "
";
}
break;
default:
break;
}
if( entity != null )
{
if( resultBuffer == null )
{
resultBuffer = new StringBuilder( string );
resultBuffer.setLength( i );
}
resultBuffer.append( entity );
}
else if( resultBuffer != null )
{
resultBuffer.append( ch );
}
last = ch;
}
return (resultBuffer != null) ? resultBuffer.toString() : string;
}
}