unEscape String
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
import java.io.PrintWriter;
import java.io.StringWriter;
import java.net.InetAddress;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.UnknownHostException;
import java.text.DateFormat;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.List;
import java.util.StringTokenizer;
import java.util.Collection;
/**
* General string utils
*/
public class StringUtils {
/**
* Unescape <code>charToEscape</code> in the string
* with the escape char <code>escapeChar</code>
*
* @param str string
* @param escapeChar escape char
* @param charToEscape the escaped char
* @return an unescaped string
*/
public static String unEscapeString(
String str, char escapeChar, char charToEscape) {
if (str == null) {
return null;
}
StringBuilder result = new StringBuilder(str.length());
boolean hasPreEscape = false;
for (int i=0; i<str.length(); i++) {
char curChar = str.charAt(i);
if (hasPreEscape) {
if (curChar != escapeChar && curChar != charToEscape) {
// no special char
throw new IllegalArgumentException("Illegal escaped string " + str +
" unescaped " + escapeChar + " at " + (i-1));
}
// otherwise discard the escape char
result.append(curChar);
hasPreEscape = false;
} else {
if (curChar == charToEscape) {
throw new IllegalArgumentException("Illegal escaped string " + str +
" unescaped " + charToEscape + " at " + i);
} else if (curChar == escapeChar) {
hasPreEscape = true;
} else {
result.append(curChar);
}
}
}
if (hasPreEscape ) {
throw new IllegalArgumentException("Illegal escaped string " + str +
", not expecting " + charToEscape + " in the end." );
}
return result.toString();
}
}