/*
* Copyright 2002-2009 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.sf.json.util;
import net.sf.json.JSONException;
import org.apache.commons.lang.StringUtils;
/**
* Transforms a string into a valid Java identifier.<br>
* There are five predefined strategies:
* <ul>
* <li>NOOP: does not perform transformation.</li>
* <li>CAMEL_CASE: follows the camel case convention, deletes non
* JavaIndentifierPart chars.</li>
* <li>UNDERSCORE: transform whitespace and non JavaIdentifierPart chars to
* '_'.</li>
* <li>WHITESPACE: deletes whitespace and non JavaIdentifierPart chars.</li>
* <li>STRICT: always throws a JSONException, does not perform transformation.</li>
* </ul>
*
* @author Andres Almiray <[email protected]>
*/
public abstract class JavaIdentifierTransformer {
/** CamelCase transformer 'camel case' => 'camelCase' */
public static final JavaIdentifierTransformer CAMEL_CASE = new CamelCaseJavaIdentifierTransformer();
/** Noop transformer '@invalid' => '@invalid' */
public static final JavaIdentifierTransformer NOOP = new NoopJavaIdentifierTransformer();
/** Strict transformer '@invalid' => JSONException */
public static final JavaIdentifierTransformer STRICT = new StrictJavaIdentifierTransformer();
/** Underscore transformer 'under score' => 'under_score' */
public static final JavaIdentifierTransformer UNDERSCORE = new UnderscoreJavaIdentifierTransformer();
/** Whitespace transformer 'white space' => 'whitespace' */
public static final JavaIdentifierTransformer WHITESPACE = new WhiteSpaceJavaIdentifierTransformer();
public abstract String transformToJavaIdentifier( String str );
/**
* Removes all non JavaIdentifier chars from the start of the string.
*
* @throws JSONException if the resulting string has zero length.
*/
protected final String shaveOffNonJavaIdentifierStartChars( String str ) {
String str2 = str;
// shave off first char if not valid
boolean ready = false;
while( !ready ){
if( !Character.isJavaIdentifierStart( str2.charAt( 0 ) ) ){
str2 = str2.substring( 1 );
if( str2.length() == 0 ){
throw new JSONException( "Can't convert '" + str + "' to a valid Java identifier" );
}
}else{
ready = true;
}
}
return str2;
}
private static final class CamelCaseJavaIdentifierTransformer extends JavaIdentifierTransformer {
public String transformToJavaIdentifier( String str ) {
if( str == null ){
return null;
}
String str2 = shaveOffNonJavaIdentifierStartChars( str );
char[] chars = str2.toCharArray();
int pos = 0;
StringBuffer buf = new StringBuffer();
boolean toUpperCaseNextChar = false;
while( pos < chars.length ){
if( !Character.isJavaIdentifierPart( chars[pos] )
|| Character.isWhitespace( chars[pos] ) ){
toUpperCaseNextChar = true;
}else{
if( toUpperCaseNextChar ){
buf.append( Character.toUpperCase( chars[pos] ) );
toUpperCaseNextChar = false;
}else{
buf.append( chars[pos] );
}
}
pos++;
}
return buf.toString();
}
}
private static final class NoopJavaIdentifierTransformer extends JavaIdentifierTransformer {
public String transformToJavaIdentifier( String str ) {
return str;
}
}
private static final class StrictJavaIdentifierTransformer extends JavaIdentifierTransformer {
public String transformToJavaIdentifier( String str ) {
throw new JSONException( "'" + str + "' is not a valid Java identifier." );
}
}
private static final class UnderscoreJavaIdentifierTransformer extends JavaIdentifierTransformer {
public String transformToJavaIdentifier( String str ) {
if( str == null ){
return null;
}
String str2 = shaveOffNonJavaIdentifierStartChars( str );
char[] chars = str2.toCharArray();
int pos = 0;
StringBuffer buf = new StringBuffer();
boolean toUnderScorePreviousChar = false;
while( pos < chars.length ){
if( !Character.isJavaIdentifierPart( chars[pos] )
|| Character.isWhitespace( chars[pos] ) ){
toUnderScorePreviousChar = true;
}else{
if( toUnderScorePreviousChar ){
buf.append( "_" );
toUnderScorePreviousChar = false;
}
buf.append( chars[pos] );
}
pos++;
}
if( buf.charAt( buf.length() - 1 ) == '_' ){
buf.deleteCharAt( buf.length() - 1 );
}
return buf.toString();
}
}
private static final class WhiteSpaceJavaIdentifierTransformer extends JavaIdentifierTransformer {
public String transformToJavaIdentifier( String str ) {
if( str == null ){
return null;
}
String str2 = shaveOffNonJavaIdentifierStartChars( str );
str2 = StringUtils.deleteWhitespace( str2 );
char[] chars = str2.toCharArray();
int pos = 0;
StringBuffer buf = new StringBuffer();
while( pos < chars.length ){
if( Character.isJavaIdentifierPart( chars[pos] ) ){
buf.append( chars[pos] );
}
pos++;
}
return buf.toString();
}
}
}
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