|
/*
* 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 {
/**
* Case insensitive check if a String starts with a specified prefix.
*
* <code>null</code>s are handled without exceptions. Two <code>null</code>
* references are considered to be equal. The comparison is case insensitive.
*
* <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);
}
/**
* Check if a String starts with a specified prefix (optionally case insensitive).
*
* @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
//-----------------------------------------------------------------------
/**
* Checks if a String is empty ("") or null.
*
* <pre>
* StringUtils.isEmpty(null) = true
* StringUtils.isEmpty("") = true
* StringUtils.isEmpty(" ") = false
* StringUtils.isEmpty("bob") = false
* StringUtils.isEmpty(" bob ") = false
* </pre>
*
* NOTE: This method changed in Lang version 2.0.
* It no longer trims the String.
* That functionality is available in isBlank().
*
* @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;
}
}
|