Main.java Source code

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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>Case insensitive check if a String starts with a specified prefix.</p>
     *
     * <p><code>null</code>s are handled without exceptions. Two <code>null</code>
     * references are considered to be equal. The comparison is case insensitive.</p>
     *
     * <pre>
     * StringUtils.startsWithIgnoreCase(null, null)      = true
     * StringUtils.startsWithIgnoreCase(null, "abcdef")  = false
     * StringUtils.startsWithIgnoreCase("abc", null)     = false
     * StringUtils.startsWithIgnoreCase("abc", "abcdef") = true
     * StringUtils.startsWithIgnoreCase("abc", "ABCDEF") = true
     * </pre>
     *
     * @see java.lang.String#startsWith(String)
     * @param str  the String to check, may be null
     * @param prefix the prefix to find, may be null
     * @return <code>true</code> if the String starts with the prefix, case insensitive, or
     *  both <code>null</code>
     * @since 2.4
     */
    public static boolean startsWithIgnoreCase(String str, String prefix) {
        return startsWith(str, prefix, true);
    }

    /**
     * <p>Check if a String starts with a specified prefix (optionally case insensitive).</p>
     *
     * @see java.lang.String#startsWith(String)
     * @param str  the String to check, may be null
     * @param prefix the prefix to find, may be null
     * @param ignoreCase inidicates whether the compare should ignore case
     *  (case insensitive) or not.
     * @return <code>true</code> if the String starts with the prefix or
     *  both <code>null</code>
     */
    private static boolean startsWith(String str, String prefix, boolean ignoreCase) {
        if (str == null || prefix == null) {
            return (str == null && prefix == null);
        }
        if (prefix.length() > str.length()) {
            return false;
        }
        return str.regionMatches(ignoreCase, 0, prefix, 0, prefix.length());
    }

    // Empty checks
    //-----------------------------------------------------------------------
    /**
     * <p>Checks if a String is empty ("") or null.</p>
     *
     * <pre>
     * StringUtils.isEmpty(null)      = true
     * StringUtils.isEmpty("")        = true
     * StringUtils.isEmpty(" ")       = false
     * StringUtils.isEmpty("bob")     = false
     * StringUtils.isEmpty("  bob  ") = false
     * </pre>
     *
     * <p>NOTE: This method changed in Lang version 2.0.
     * It no longer trims the String.
     * That functionality is available in isBlank().</p>
     *
     * @param str  the String to check, may be null
     * @return <code>true</code> if the String is empty or null
     */
    public static boolean isEmpty(String str) {
        return str == null || str.length() == 0;
    }

}