StringUtils.java Source code

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Here is the source code for StringUtils.java

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/*
JSPWiki - a JSP-based WikiWiki clone.
    
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.security.SecureRandom;
import java.util.Properties;
import java.util.Random;

public class StringUtils {

    /**
     *  Replaces the relevant entities inside the String.
     *  All & >, <, and " are replaced by their
     *  respective names.
     *
     *  @since 1.6.1
     *  @param src The source string.
     *  @return The encoded string.
     */
    public static String replaceEntities(String src) {
        src = replaceString(src, "&", "&");
        src = replaceString(src, "<", "&lt;");
        src = replaceString(src, ">", "&gt;");
        src = replaceString(src, "\"", "&quot;");

        return src;
    }

    /**
     *  Replaces a string with an other string.
     *
     *  @param orig Original string.  Null is safe.
     *  @param src  The string to find.
     *  @param dest The string to replace <I>src</I> with.
     *  @return A string with the replacement done.
     */
    public static final String replaceString(String orig, String src, String dest) {
        if (orig == null)
            return null;
        if (src == null || dest == null)
            throw new NullPointerException();
        if (src.length() == 0)
            return orig;

        StringBuffer res = new StringBuffer(orig.length() + 20); // Pure guesswork
        int start = 0;
        int end = 0;
        int last = 0;

        while ((start = orig.indexOf(src, end)) != -1) {
            res.append(orig.substring(last, start));
            res.append(dest);
            end = start + src.length();
            last = start + src.length();
        }

        res.append(orig.substring(end));

        return res.toString();
    }

    /**
     *  Replaces a part of a string with a new String.
     *
     *  @param start Where in the original string the replacing should start.
     *  @param end Where the replacing should end.
     *  @param orig Original string.  Null is safe.
     *  @param text The new text to insert into the string.
     *  @return The string with the orig replaced with text.
     */
    public static String replaceString(String orig, int start, int end, String text) {
        if (orig == null)
            return null;

        StringBuffer buf = new StringBuffer(orig);

        buf.replace(start, end, text);

        return buf.toString();
    }

    /**
     *  Replaces a string with an other string. Case insensitive matching is used
     *
     *  @param orig Original string.  Null is safe.
     *  @param src  The string to find.
     *  @param dest The string to replace <I>src</I> with.
     *  @return A string with all instances of src replaced with dest.
     */
    public static String replaceStringCaseUnsensitive(String orig, String src, String dest) {
        if (orig == null)
            return null;

        StringBuffer res = new StringBuffer();
        int start = 0;
        int end = 0;
        int last = 0;

        String origCaseUnsn = orig.toLowerCase();
        String srcCaseUnsn = src.toLowerCase();

        while ((start = origCaseUnsn.indexOf(srcCaseUnsn, end)) != -1) {
            res.append(orig.substring(last, start));
            res.append(dest);
            end = start + src.length();
            last = start + src.length();
        }

        res.append(orig.substring(end));

        return res.toString();
    }

}