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Karaf Util contains utility classes used in different Karaf modules.
/*
* 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.
*/
package org.apache.karaf.util;
import java.util.Locale;
/**
* Util class to manipulate String, especially around escape/unescape.
*/
public class StringEscapeUtils {
/** Constant for the radix of hex numbers.*/
private static final int HEX_RADIX = 16;
/** Constant for the length of a unicode literal.*/
private static final int UNICODE_LEN = 4;
/**
* Unescapes any Java literals found in the String to a
* Writer.
This is a slightly modified version of the
* StringEscapeUtils.unescapeJava() function in commons-lang that doesn't
* drop escaped separators (i.e '\,').
*
* @param str the String to unescape, may be null
* @return the processed string
* @throws IllegalArgumentException if the Writer is null
*/
public static String unescapeJava(String str) {
if (str == null) {
return null;
}
int sz = str.length();
StringBuffer out = new StringBuffer(sz);
StringBuffer unicode = new StringBuffer(UNICODE_LEN);
boolean hadSlash = false;
boolean inUnicode = false;
for (int i = 0; i < sz; i++) {
char ch = str.charAt(i);
if (inUnicode) {
// if in unicode, then we're reading unicode
// values in somehow
unicode.append(ch);
if (unicode.length() == UNICODE_LEN) {
// unicode now contains the four hex digits
// which represents our unicode character
try {
int value = Integer.parseInt(unicode.toString(), HEX_RADIX);
out.append((char) value);
unicode.setLength(0);
inUnicode = false;
hadSlash = false;
} catch (NumberFormatException nfe) {
throw new IllegalArgumentException("Unable to parse unicode value: " + unicode, nfe);
}
}
continue;
}
if (hadSlash) {
// handle an escaped value
hadSlash = false;
switch (ch) {
case '\\' :
out.append('\\');
break;
case '\'' :
out.append('\'');
break;
case '\"' :
out.append('"');
break;
case 'r' :
out.append('\r');
break;
case 'f' :
out.append('\f');
break;
case 't' :
out.append('\t');
break;
case 'n' :
out.append('\n');
break;
case 'b' :
out.append('\b');
break;
case 'u' :
// uh-oh, we're in unicode country....
inUnicode = true;
break;
default :
out.append(ch);
break;
}
continue;
} else if (ch == '\\') {
hadSlash = true;
continue;
}
out.append(ch);
}
if (hadSlash) {
// then we're in the weird case of a \ at the end of the
// string, let's output it anyway.
out.append('\\');
}
return out.toString();
}
/**
* Escapes the characters in a String using Java String rules.
*
* Deals correctly with quotes and control-chars (tab, backslash, cr, ff, etc.)
*
* So a tab becomes the characters '\\' and
* 't'.
*
* The only difference between Java strings and JavaScript strings
* is that in JavaScript, a single quote must be escaped.
*
* Example:
*
* input string: He didn't say, "Stop!"
* output string: He didn't say, \"Stop!\"
*
*
*
* @param str String to escape values in, may be null
* @return String with escaped values, null if null string input
*/
public static String escapeJava(String str) {
if (str == null) {
return null;
}
int sz = str.length();
StringBuffer out = new StringBuffer(sz * 2);
for (int i = 0; i < sz; i++) {
char ch = str.charAt(i);
// handle unicode
if (ch > 0xfff) {
out.append("\\u").append(hex(ch));
} else if (ch > 0xff) {
out.append("\\u0").append(hex(ch));
} else if (ch > 0x7f) {
out.append("\\u00").append(hex(ch));
} else if (ch < 32) {
switch (ch) {
case '\b' :
out.append('\\');
out.append('b');
break;
case '\n' :
out.append('\\');
out.append('n');
break;
case '\t' :
out.append('\\');
out.append('t');
break;
case '\f' :
out.append('\\');
out.append('f');
break;
case '\r' :
out.append('\\');
out.append('r');
break;
default :
if (ch > 0xf) {
out.append("\\u00").append(hex(ch));
} else {
out.append("\\u000").append(hex(ch));
}
break;
}
} else {
switch (ch) {
case '"' :
out.append('\\');
out.append('"');
break;
case '\\' :
out.append('\\');
out.append('\\');
break;
default :
out.append(ch);
break;
}
}
}
return out.toString();
}
/**
* Returns an upper case hexadecimal String for the given
* character.
*
* @param ch The character to convert.
* @return An upper case hexadecimal String
*/
public static String hex(char ch) {
return Integer.toHexString(ch).toUpperCase(Locale.ENGLISH);
}
}