Java tutorial
/********************************************************************************** * * Copyright (c) 2003, 2004, 2007, 2008 The Sakai Foundation * * Licensed under the Educational Community 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.opensource.org/licenses/ECL-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 edu.indiana.lib.twinpeaks.util; import java.io.*; import java.util.*; import java.util.regex.*; public class StringUtils { private static org.apache.commons.logging.Log _log = LogUtils.getLog(StringUtils.class); /** * Minimum length supported by <code>truncateAtWhitespace()</code> */ private static final int MINIMUM_SUPPORTED_LENGTH = 4; private StringUtils() { } /** * Replace all occurances of the target text with the provided replacement * text. Both target and replacement may be regular expressions - see * <code>java.util.regex.Matcher</code>. * @param text Text to modify * @param targetText Text to find and replace * @param newText New text * @return Updated text */ public static String replace(String text, String targetText, String newText) { Pattern pattern = Pattern.compile(targetText, Pattern.CASE_INSENSITIVE); Matcher matcher = pattern.matcher(text); return matcher.replaceAll(newText); } /** * Null (or zero-length) String? */ public static boolean isNull(String string) { return (string == null) || (string.length() == 0); } /** * Truncate text on a whitespace boundary (near a specified length). * The length of the resultant string will be in the range:<br> * <code> (requested-length * .25) ~ (requested-length * 1.5) </code> * @param text Text to truncate * @param length Target length * @return Truncated text */ public static String truncateAtWhitespace(String text, int length) { int desired, lowerBound, upperBound; /* * Make sure we have a reasonable length to work with */ if (length < MINIMUM_SUPPORTED_LENGTH) { throw new IllegalArgumentException( "Requested length too short (must be " + MINIMUM_SUPPORTED_LENGTH + " or greated)"); } /* * No need to truncate - the original string "fits" */ if (text.length() <= length) { return text; } /* * Try to find whitespace befor the requested maximum */ lowerBound = length / 4; upperBound = length + (length / 2); for (int i = length - 1; i > lowerBound; i--) { if (Character.isWhitespace(text.charAt(i))) { return text.substring(0, i); } } /* * No whitespace - look beyond the desired maximum */ for (int i = (length); i < upperBound; i++) { if (Character.isWhitespace(text.charAt(i))) { return text.substring(0, i); } } /* * No whitespace, just truncate the text at the requested length */ return text.substring(0, length); } /** * Trim specified charcater from front of string * @param text Text * @param character Character to remove * @return Trimmed text */ public static String trimFront(String text, char character) { String normalizedText; int index; if (StringUtils.isNull(text)) { return text; } normalizedText = text.trim(); index = 0; while (normalizedText.charAt(index) == character) { if (++index >= normalizedText.length()) break; } return normalizedText.substring(index).trim(); } /** * Trim specified charcater from end of string * @param text Text * @param character Character to remove * @return Trimmed text */ public static String trimEnd(String text, char character) { String normalizedText; int index; if (StringUtils.isNull(text)) { return text; } normalizedText = text.trim(); index = normalizedText.length() - 1; while (normalizedText.charAt(index) == character) { if (--index < 0) { return ""; } } return normalizedText.substring(0, index + 1).trim(); } /** * Trim specified charcater from both ends of a String * @param text Text * @param character Character to remove * @return Trimmed text */ public static String trimAll(String text, char character) { String normalizedText = trimFront(text, character); return trimEnd(normalizedText, character); } /** * Capitlize each word in a string (journal titles, etc) * @param text Text to inspect * @return Capitalized text */ public static String capitalize(String text) { StringBuilder resultText; char previousC; resultText = new StringBuilder(); previousC = '.'; for (int i = 0; i < text.length(); i++) { char c = text.charAt(i); if (Character.isLetter(c) && !Character.isLetter(previousC)) { resultText.append(Character.toUpperCase(c)); } else { resultText.append(c); } previousC = c; } return resultText.toString(); } /** * Remove a character (or range of characters) from a string. If the * character is in a word, remove the entire word. * @param source String to edit * @param pattern Character (or range) to remove. Range is a regular * expression: <code>[\u002c-\u002f]</code> or <code>[,-/]</code> * @return Modified text */ public static String removeCharacterOrRangeAsWord(String source, String pattern) { return removeCharacterOrRange(source, pattern, true); } /** * Remove a character (or range of characters) from a string. If the * character is at the start or end of a word, remove the character only * (leave the word in place). * @param source String to edit * @param pattern Character (or range) to remove. Range is a regular * expression: <code>[\u002c-\u002f]</code> or <code>[,-/]</code> * @return Modified text */ public static String removeCharacterOrRangeAsCharacter(String source, String pattern) { return removeCharacterOrRange(source, pattern, false); } /* * Helpers */ /** * Remove a character (or range of characters) from a string. * [optional] If a character is embedded in a word, remove the entire word. * @param source String to edit * @param pattern Character (or range) to remove. Range is a regular * expression: <code>[\u002c-\u002f]</code> or <code>[,-/]</code> * @param removeAsWord Always remove entire word? * @return Modified text */ private static String removeCharacterOrRange(String source, String pattern, boolean removeAsWord) { StringBuilder patternBuffer = new StringBuilder(); String rangePattern, result; patternBuffer.append('['); patternBuffer.append(pattern); patternBuffer.append(']'); rangePattern = patternBuffer.toString(); result = StringUtils.replace(source, "\\S+" + rangePattern + "\\S+", ""); if (removeAsWord) { result = StringUtils.replace(result, rangePattern + "\\S+", ""); result = StringUtils.replace(result, "\\S+" + rangePattern, ""); } return StringUtils.replace(result, rangePattern, " "); } /* * Test */ public static void main(String[] args) throws Exception { System.out.println(StringUtils.replace(args[0], args[1], args[2])); } }