Abbreviates a String using ellipses. - Java java.lang

Java examples for java.lang:String Truncate

  1. HOME
  2. Java
  3. java.lang
  4. String Truncate

Description

Abbreviates a String using ellipses.

Demo Code


/*//from ww w .jav a 2  s .c  o  m
 * Copyright 2013 Guidewire Software, Inc.
 */
/**
 * This class is based, in part, on org.apache.commons.lang.StringUtils and is intended
 * to break the dependency on that project.
 *
 * @author <a href="http://jakarta.apache.org/turbine/">Apache Jakarta Turbine</a>
 * @author <a href="mailto:jon@latchkey.com">Jon S. Stevens</a>
 * @author Daniel L. Rall
 * @author <a href="mailto:gcoladonato@yahoo.com">Greg Coladonato</a>
 * @author <a href="mailto:ed@apache.org">Ed Korthof</a>
 * @author <a href="mailto:rand_mcneely@yahoo.com">Rand McNeely</a>
 * @author Stephen Colebourne
 * @author <a href="mailto:fredrik@westermarck.com">Fredrik Westermarck</a>
 * @author Holger Krauth
 * @author <a href="mailto:alex@purpletech.com">Alexander Day Chaffee</a>
 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
 * @author Arun Mammen Thomas
 * @author Gary Gregory
 * @author Phil Steitz
 * @author Al Chou
 * @author Michael Davey
 * @author Reuben Sivan
 * @author Chris Hyzer
 *  Johnson

 */
 
//package com.java2s;

public class Main {
    public static void main(String[] argv) {
        String str = "java2s.com";
        int maxWidth = 42;
        System.out.println(abbreviate(str, maxWidth));
    }

    /**
     * <p>Abbreviates a String using ellipses. This will turn
     * "Now is the time for all good men" into "Now is the time for..."</p>
     *
     * <p>Specifically:
     * <ul>
     *   <li>If <code>str</code> is less than <code>maxWidth</code> characters
     *       long, return it.</li>
     *   <li>Else abbreviate it to <code>(substring(str, 0, max-3) + "...")</code>.</li>
     *   <li>If <code>maxWidth</code> is less than <code>4</code>, throw an
     *       <code>IllegalArgumentException</code>.</li>
     *   <li>In no case will it return a String of length greater than
     *       <code>maxWidth</code>.</li>
     * </ul>
     * </p>
     *
     * <pre>
     * abbreviate(null, *)      = null
     * abbreviate("", 4)        = ""
     * abbreviate("abcdefg", 6) = "abc..."
     * abbreviate("abcdefg", 7) = "abcdefg"
     * abbreviate("abcdefg", 8) = "abcdefg"
     * abbreviate("abcdefg", 4) = "a..."
     * abbreviate("abcdefg", 3) = IllegalArgumentException
     * </pre>
     *
     * @param str  the String to check, may be null
     * @param maxWidth  maximum length of result String, must be at least 4
     * @return abbreviated String, <code>null</code> if null String input
     * @throws IllegalArgumentException if the width is too small
     * @since 2.0
     */
    public static String abbreviate(String str, int maxWidth) {
        return abbreviate(str, 0, maxWidth);
    }

    /**
     * <p>Abbreviates a String using ellipses. This will turn
     * "Now is the time for all good men" into "...is the time for..."</p>
     *
     * <p>Works like <code>abbreviate(String, int)</code>, but allows you to specify
     * a "left edge" offset.  Note that this left edge is not necessarily going to
     * be the leftmost character in the result, or the first character following the
     * ellipses, but it will appear somewhere in the result.
     *
     * <p>In no case will it return a String of length greater than
     * <code>maxWidth</code>.</p>
     *
     * <pre>
     * abbreviate(null, *, *)                = null
     * abbreviate("", 0, 4)                  = ""
     * abbreviate("abcdefghijklmno", -1, 10) = "abcdefg..."
     * abbreviate("abcdefghijklmno", 0, 10)  = "abcdefg..."
     * abbreviate("abcdefghijklmno", 1, 10)  = "abcdefg..."
     * abbreviate("abcdefghijklmno", 4, 10)  = "abcdefg..."
     * abbreviate("abcdefghijklmno", 5, 10)  = "...fghi..."
     * abbreviate("abcdefghijklmno", 6, 10)  = "...ghij..."
     * abbreviate("abcdefghijklmno", 8, 10)  = "...ijklmno"
     * abbreviate("abcdefghijklmno", 10, 10) = "...ijklmno"
     * abbreviate("abcdefghijklmno", 12, 10) = "...ijklmno"
     * abbreviate("abcdefghij", 0, 3)        = IllegalArgumentException
     * abbreviate("abcdefghij", 5, 6)        = IllegalArgumentException
     * </pre>
     *
     * @param str  the String to check, may be null
     * @param offset  left edge of source String
     * @param maxWidth  maximum length of result String, must be at least 4
     * @return abbreviated String, <code>null</code> if null String input
     * @throws IllegalArgumentException if the width is too small
     * @since 2.0
     */
    public static String abbreviate(String str, int offset, int maxWidth) {
        if (str == null) {
            return null;
        }
        if (maxWidth < 4) {
            throw new IllegalArgumentException(
                    "Minimum abbreviation width is 4");
        }
        if (str.length() <= maxWidth) {
            return str;
        }
        if (offset > str.length()) {
            offset = str.length();
        }
        if ((str.length() - offset) < (maxWidth - 3)) {
            offset = str.length() - (maxWidth - 3);
        }
        if (offset <= 4) {
            return str.substring(0, maxWidth - 3) + "...";
        }
        if (maxWidth < 7) {
            throw new IllegalArgumentException(
                    "Minimum abbreviation width with offset is 7");
        }
        if ((offset + (maxWidth - 3)) < str.length()) {
            return "..." + abbreviate(str.substring(offset), maxWidth - 3);
        }
        return "..." + str.substring(str.length() - (maxWidth - 3));
    }
}

Related Tutorials