Here you can find the source of rightPad(String str, int size, char padChar)
Right pad a String with a specified character.
The String is padded to the size of size.
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"
| Parameter | Description |
|---|---|
| str | the String to pad out, may be null |
| size | the size to pad to |
| padChar | the character to pad with |
null if null String input
public static String rightPad(String str, int size, char padChar)
//package com.java2s; /*//from w w w . j a v a 2s.c o m * Copyright 2002-2005 The Apache Software Foundation. * * 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. */ public class Main { /** * The empty String <code>""</code>. * @since 2.0 */ public static final String EMPTY = ""; /** * <p>The maximum size to which the padding constant(s) can expand.</p> */ private static final int PAD_LIMIT = 8192; /** * <p>An array of <code>String</code>s used for padding.</p> * * <p>Used for efficient space padding. The length of each String expands as needed.</p> */ private static final String[] PADDING = new String[Character.MAX_VALUE]; /** * <p>Right pad a String with spaces (' ').</p> * * <p>The String is padded to the size of <code>size</code>.</p> * * <pre> * StringUtils.rightPad(null, *) = null * StringUtils.rightPad("", 3) = " " * StringUtils.rightPad("bat", 3) = "bat" * StringUtils.rightPad("bat", 5) = "bat " * StringUtils.rightPad("bat", 1) = "bat" * StringUtils.rightPad("bat", -1) = "bat" * </pre> * * @param str the String to pad out, may be null * @param size the size to pad to * @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) { return rightPad(str, size, ' '); } /** * <p>Right pad a String with a specified character.</p> * * <p>The String is padded to the size of <code>size</code>.</p> * * <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)); } /** * <p>Right pad a String with a specified String.</p> * * <p>The String is padded to the size of <code>size</code>.</p> * * <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)); } } /** * <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> * * @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> */ private static String padding(int repeat, char padChar) { // be careful of synchronization in this method // we are assuming that get and set from an array index is atomic String pad = PADDING[padChar]; if (pad == null) { pad = String.valueOf(padChar); } while (pad.length() < repeat) { pad = pad.concat(pad); } PADDING[padChar] = pad; return pad.substring(0, repeat); } /** * <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>Gets a substring from the specified String avoiding exceptions.</p> * * <p>A negative start position can be used to start <code>n</code> * characters from the end of the String.</p> * * <p>A <code>null</code> String will return <code>null</code>. * An empty ("") String will return "".</p> * * <pre> * StringUtils.substring(null, *) = null * StringUtils.substring("", *) = "" * StringUtils.substring("abc", 0) = "abc" * StringUtils.substring("abc", 2) = "c" * StringUtils.substring("abc", 4) = "" * StringUtils.substring("abc", -2) = "bc" * StringUtils.substring("abc", -4) = "abc" * </pre> * * @param str the String to get the substring from, may be null * @param start the position to start from, negative means * count back from the end of the String by this many characters * @return substring from start position, <code>null</code> if null String input */ public static String substring(String str, int start) { if (str == null) { return null; } // handle negatives, which means last n characters if (start < 0) { start = str.length() + start; // remember start is negative } if (start < 0) { start = 0; } if (start > str.length()) { return EMPTY; } return str.substring(start); } /** * <p>Gets a substring from the specified String avoiding exceptions.</p> * * <p>A negative start position can be used to start/end <code>n</code> * characters from the end of the String.</p> * * <p>The returned substring starts with the character in the <code>start</code> * position and ends before the <code>end</code> position. All position counting is * zero-based -- i.e., to start at the beginning of the string use * <code>start = 0</code>. Negative start and end positions can be used to * specify offsets relative to the end of the String.</p> * * <p>If <code>start</code> is not strictly to the left of <code>end</code>, "" * is returned.</p> * * <pre> * StringUtils.substring(null, *, *) = null * StringUtils.substring("", * , *) = ""; * StringUtils.substring("abc", 0, 2) = "ab" * StringUtils.substring("abc", 2, 0) = "" * StringUtils.substring("abc", 2, 4) = "c" * StringUtils.substring("abc", 4, 6) = "" * StringUtils.substring("abc", 2, 2) = "" * StringUtils.substring("abc", -2, -1) = "b" * StringUtils.substring("abc", -4, 2) = "ab" * </pre> * * @param str the String to get the substring from, may be null * @param start the position to start from, negative means * count back from the end of the String by this many characters * @param end the position to end at (exclusive), negative means * count back from the end of the String by this many characters * @return substring from start position to end positon, * <code>null</code> if null String input */ public static String substring(String str, int start, int end) { if (str == null) { return null; } // handle negatives if (end < 0) { end = str.length() + end; // remember end is negative } if (start < 0) { start = str.length() + start; // remember start is negative } // check length next if (end > str.length()) { end = str.length(); } // if start is greater than end, return "" if (start > end) { return EMPTY; } if (start < 0) { start = 0; } if (end < 0) { end = 0; } return str.substring(start, end); } }