Main.java Source code

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Here is the source code for Main.java

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/*
 * 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.
 */

public class Main {

    /**
     * <p>Swaps the case of a String changing upper and title case to
     * lower case, and lower case to upper case.</p>
     *
     * <ul>
     *  <li>Upper case character converts to Lower case</li>
     *  <li>Title case character converts to Lower case</li>
     *  <li>Lower case character converts to Upper case</li>
     * </ul>
     *
     * <p>For a word based algorithm, see {@link WordUtils#swapCase(String)}.
     * 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>
     *
     * <p>NOTE: This method changed in Lang version 2.0.
     * It no longer performs a word based algorithm.
     * If you only use ASCII, you will notice no change.
     * That functionality is available in WordUtils.</p>
     *
     * @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;
        }
        StringBuffer buffer = new StringBuffer(strLen);

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