Abbreviate string : String Format « Data Type « Java Tutorial

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2. Data Type
3. String Format

/**
 * $Revision: 10205 $
 * $Date: 2008-04-11 15:48:27 -0700 (Fri, 11 Apr 2008) $
 *
 * Copyright (C) 2004-2008 Jive Software. All rights reserved.
 *
 * This software is published under the terms of the GNU Public License (GPL),
 * a copy of which is included in this distribution, or a commercial license
 * agreement with Jive.
 */

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.text.BreakIterator;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;

/**
 * Utility class to peform common String manipulation algorithms.
 */
public class StringUtils {

    // Constants used by escapeHTMLTags
    private static final char[] QUOTE_ENCODE = """.toCharArray();
    private static final char[] AMP_ENCODE = "&".toCharArray();
    private static final char[] LT_ENCODE = "<".toCharArray();
    private static final char[] GT_ENCODE = ">".toCharArray();

    private StringUtils() {
        // Not instantiable.
    }


    /**
     * Abbreviates a string to a specified length and then adds an ellipsis
     * if the input is greater than the maxWidth. Example input:
     * <pre>
     *      user1@jivesoftware.com/home
     * </pre>
     * and a maximum length of 20 characters, the abbreviate method will return:
     * <pre>
     *      user1@jivesoftware.c...
     * </pre>
     * @param str the String to abbreviate.
     * @param maxWidth the maximum size of the string, minus the ellipsis.
     * @return the abbreviated String, or <tt>null</tt> if the string was <tt>null</tt>.
     */
    public static String abbreviate(String str, int maxWidth) {
        if (null == str) {
            return null;
        }

        if (str.length() <= maxWidth) {
            return str;
        }
        
        return str.substring(0, maxWidth) + "...";
    }

}