/*
* Copyright 2009-2013 the original author or authors.
*
* Licensed 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.
*/
package org.springframework.shell.support.util;
/**
* Utility methods for Strings focused on the use in formatting of tables. padLeft methods taken from
* Commons Lang 2.6 to avoid an extra compile time dependency.
*
* @author Gunnar Hillert
* @author Mark Pollack
*
*/
public class StringUtils {
/**
* <p>
* The maximum size to which the padding constant(s) can expand.
* </p>
*/
private static final int PAD_LIMIT = 8192;
/**
* <p>
* Left pad a String with spaces (' ').
* </p>
*
* <p>
* The String is padded to the size of <code>size</code>.
* </p>
*
* <pre>
* StringUtils.leftPad(null, *) = null
* StringUtils.leftPad("", 3) = " "
* StringUtils.leftPad("bat", 3) = "bat"
* StringUtils.leftPad("bat", 5) = " bat"
* StringUtils.leftPad("bat", 1) = "bat"
* StringUtils.leftPad("bat", -1) = "bat"
* </pre>
*
* @param str
* the String to pad out, may be null
* @param size
* the size to pad to
* @return left padded String or original String if no padding is necessary,
* <code>null</code> if null String input
*/
public static String padLeft(String str, int size) {
return padLeft(str, size, ' ');
}
/**
* <p>
* Left pad a String with a specified character.
* </p>
*
* <p>
* Pad to a size of <code>size</code>.
* </p>
*
* <pre>
* StringUtils.leftPad(null, *, *) = null
* StringUtils.leftPad("", 3, 'z') = "zzz"
* StringUtils.leftPad("bat", 3, 'z') = "bat"
* StringUtils.leftPad("bat", 5, 'z') = "zzbat"
* StringUtils.leftPad("bat", 1, 'z') = "bat"
* StringUtils.leftPad("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 left padded String or original String if no padding is necessary,
* <code>null</code> if null String input
* @since 2.0
*/
public static String padLeft(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 padLeft(str, size, String.valueOf(padChar));
}
return padding(pads, padChar).concat(str);
}
/**
* <p>
* Left pad a String with a specified String.
* </p>
*
* <p>
* Pad to a size of <code>size</code>.
* </p>
*
* <pre>
* StringUtils.leftPad(null, *, *) = null
* StringUtils.leftPad("", 3, "z") = "zzz"
* StringUtils.leftPad("bat", 3, "yz") = "bat"
* StringUtils.leftPad("bat", 5, "yz") = "yzbat"
* StringUtils.leftPad("bat", 8, "yz") = "yzyzybat"
* StringUtils.leftPad("bat", 1, "yz") = "bat"
* StringUtils.leftPad("bat", -1, "yz") = "bat"
* StringUtils.leftPad("bat", 5, null) = " bat"
* StringUtils.leftPad("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 left padded String or original String if no padding is necessary,
* <code>null</code> if null String input
*/
public static String padLeft(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 padLeft(str, size, padStr.charAt(0));
}
if (pads == padLen) {
return padStr.concat(str);
} else if (pads < padLen) {
return padStr.substring(0, pads).concat(str);
} else {
char[] padding = new char[pads];
char[] padChars = padStr.toCharArray();
for (int i = 0; i < pads; i++) {
padding[i] = padChars[i % padLen];
}
return new String(padding).concat(str);
}
}
/**
* <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;
}
/**
* <p>
* Returns padding using the specified delimiter repeated to a given length.
* </p>
*
* <pre>
* StringUtils.padding(0, 'e') = ""
* StringUtils.padding(3, 'e') = "eee"
* StringUtils.padding(-2, 'e') = IndexOutOfBoundsException
* </pre>
*
* <p>
* 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.
* </p>
*
* @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);
}
/**
* Right-pad a String with a configurable padding character.
*
* @param inputString
* The String to pad. A {@code null} String will be treated like
* an empty String.
* @param size
* Pad String by the number of characters.
* @param paddingChar
* The character to pad the String with.
* @return The padded String. If the provided String is null, an empty
* String is returned.
*/
public static String padRight(String inputString, int size, char paddingChar) {
final String stringToPad;
if (inputString == null) {
stringToPad = "";
} else {
stringToPad = inputString;
}
StringBuilder padded = new StringBuilder(stringToPad);
while (padded.length() < size) {
padded.append(paddingChar);
}
return padded.toString();
}
/**
* Right-pad the provided String with empty spaces.
*
* @param string
* The String to pad
* @param size
* Pad String by the number of characters.
* @return The padded String. If the provided String is null, an empty
* String is returned.
*/
public static String padRight(String string, int size) {
return padRight(string, size, ' ');
}
}