|
/*
* 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 {
/**
* The maximum size to which the padding constant(s) can expand.
*/
private static final int PAD_LIMIT = 8192;
/**
* Right pad a String with a specified character.
*
* The String is padded to the size of <code>size</code>.
*
* <pre>
* StringUtils.rightPad(null, *, *) = null
* StringUtils.rightPad("", 3, 'z') = "zzz"
* StringUtils.rightPad("bat", 3, 'z') = "bat"
* StringUtils.rightPad("bat", 5, 'z') = "batzz"
* StringUtils.rightPad("bat", 1, 'z') = "bat"
* StringUtils.rightPad("bat", -1, 'z') = "bat"
* </pre>
*
* @param str the String to pad out, may be null
* @param size the size to pad to
* @param padChar the character to pad with
* @return right padded String or original String if no padding is necessary,
* <code>null</code> if null String input
* @since 2.0
*/
public static String rightPad(String str, int size, char padChar) {
if (str == null) {
return null;
}
int pads = size - str.length();
if (pads <= 0) {
return str; // returns original String when possible
}
if (pads > PAD_LIMIT) {
return rightPad(str, size, String.valueOf(padChar));
}
return str.concat(padding(pads, padChar));
}
/**
* Right pad a String with a specified String.
*
* The String is padded to the size of <code>size</code>.
*
* <pre>
* StringUtils.rightPad(null, *, *) = null
* StringUtils.rightPad("", 3, "z") = "zzz"
* StringUtils.rightPad("bat", 3, "yz") = "bat"
* StringUtils.rightPad("bat", 5, "yz") = "batyz"
* StringUtils.rightPad("bat", 8, "yz") = "batyzyzy"
* StringUtils.rightPad("bat", 1, "yz") = "bat"
* StringUtils.rightPad("bat", -1, "yz") = "bat"
* StringUtils.rightPad("bat", 5, null) = "bat "
* StringUtils.rightPad("bat", 5, "") = "bat "
* </pre>
*
* @param str the String to pad out, may be null
* @param size the size to pad to
* @param padStr the String to pad with, null or empty treated as single space
* @return right padded String or original String if no padding is necessary,
* <code>null</code> if null String input
*/
public static String rightPad(String str, int size, String padStr) {
if (str == null) {
return null;
}
if (isEmpty(padStr)) {
padStr = " ";
}
int padLen = padStr.length();
int strLen = str.length();
int pads = size - strLen;
if (pads <= 0) {
return str; // returns original String when possible
}
if (padLen == 1 && pads <= PAD_LIMIT) {
return rightPad(str, size, padStr.charAt(0));
}
if (pads == padLen) {
return str.concat(padStr);
} else if (pads < padLen) {
return str.concat(padStr.substring(0, pads));
} else {
char[] padding = new char[pads];
char[] padChars = padStr.toCharArray();
for (int i = 0; i < pads; i++) {
padding[i] = padChars[i % padLen];
}
return str.concat(new String(padding));
}
}
/**
* Returns padding using the specified delimiter repeated
* to a given length.
*
* <pre>
* StringUtils.padding(0, 'e') = ""
* StringUtils.padding(3, 'e') = "eee"
* StringUtils.padding(-2, 'e') = IndexOutOfBoundsException
* </pre>
*
* Note: this method doesn't not support padding with
* <a href="http://www.unicode.org/glossary/#supplementary_character">Unicode Supplementary Characters</a>
* as they require a pair of <code>char</code>s to be represented.
* If you are needing to support full I18N of your applications
* consider using {@link #repeat(String, int)} instead.
*
*
* @param repeat number of times to repeat delim
* @param padChar character to repeat
* @return String with repeated character
* @throws IndexOutOfBoundsException if <code>repeat < 0</code>
* @see #repeat(String, int)
*/
private static String padding(int repeat, char padChar) throws IndexOutOfBoundsException {
if (repeat < 0) {
throw new IndexOutOfBoundsException("Cannot pad a negative amount: " + repeat);
}
final char[] buf = new char[repeat];
for (int i = 0; i < buf.length; i++) {
buf[i] = padChar;
}
return new String(buf);
}
// 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;
}
}
|