Swaps the case of a String using a word based algorithm. - Android java.lang

Android examples for java.lang:String Case

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Description

Swaps the case of a String using a word based algorithm.

Demo Code

/*******************************************************************************
 * Copyright (c) 2011 MadRobot./*from ww  w  . j  av  a  2  s. c o m*/
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the GNU Lesser Public License v2.1
 * which accompanies this distribution, and is available at
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * 
 * Contributors:
 *  Elton Kent - initial API and implementation
 ******************************************************************************/
//package com.java2s;

public class Main {
    /**
     * <p>
     * Swaps the case of a String using a word based algorithm.
     * </p>
     * 
     * <ul>
     * <li>Upper case character converts to Lower case</li>
     * <li>Title case character converts to Lower case</li>
     * <li>Lower case character after Whitespace or at start converts to Title
     * case</li>
     * <li>Other Lower case character converts to Upper case</li>
     * </ul>
     * 
     * <p>
     * Whitespace is defined by {@link Character#isWhitespace(char)}. A
     * <code>null</code> input String returns <code>null</code>.
     * </p>
     * 
     * <pre>
     * StringUtils.swapCase(null)                 = null
     * StringUtils.swapCase("")                   = ""
     * StringUtils.swapCase("The dog has a BONE") = "tHE DOG HAS A bone"
     * </pre>
     * 
     * @param str
     *            the String to swap case, may be null
     * @return the changed String, <code>null</code> if null String input
     */
    public static String swapCase(String str) {
        int strLen;
        if (str == null || (strLen = str.length()) == 0) {
            return str;
        }
        StringBuilder buffer = new StringBuilder(strLen);

        boolean whitespace = true;
        char ch = 0;
        char tmp = 0;

        for (int i = 0; i < strLen; i++) {
            ch = str.charAt(i);
            if (Character.isUpperCase(ch)) {
                tmp = Character.toLowerCase(ch);
            } else if (Character.isTitleCase(ch)) {
                tmp = Character.toLowerCase(ch);
            } else if (Character.isLowerCase(ch)) {
                if (whitespace) {
                    tmp = Character.toTitleCase(ch);
                } else {
                    tmp = Character.toUpperCase(ch);
                }
            } else {
                tmp = ch;
            }
            buffer.append(tmp);
            whitespace = Character.isWhitespace(ch);
        }
        return buffer.toString();
    }
}

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