Java tutorial
/* * 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. * */ package org.apache.commons.exec.util; import java.io.File; import java.util.ArrayList; import java.util.List; import java.util.Map; import java.util.StringTokenizer; /** * Supplement of commons-lang, the stringSubstitution() was in a simpler * implementation available in an older commons-lang implementation. * * This class is not part of the public API and could change without * warning. * * @version $Id: StringUtils.java 1636204 2014-11-02 22:30:31Z ggregory $ */ public class StringUtils { private static final String SINGLE_QUOTE = "\'"; private static final String DOUBLE_QUOTE = "\""; private static final char SLASH_CHAR = '/'; private static final char BACKSLASH_CHAR = '\\'; /** * Perform a series of substitutions. * <p> * The substitutions are performed by replacing ${variable} in the target string with the value of provided by the * key "variable" in the provided hash table. * </p> * <p> * A key consists of the following characters: * </p> * <ul> * <li>letter * <li>digit * <li>dot character * <li>hyphen character * <li>plus character * <li>underscore character * </ul> * * @param argStr * the argument string to be processed * @param vars * name/value pairs used for substitution * @param isLenient * ignore a key not found in vars or throw a RuntimeException? * @return String target string with replacements. */ public static StringBuffer stringSubstitution(final String argStr, final Map<? super String, ?> vars, final boolean isLenient) { final StringBuffer argBuf = new StringBuffer(); if (argStr == null || argStr.length() == 0) { return argBuf; } if (vars == null || vars.size() == 0) { return argBuf.append(argStr); } final int argStrLength = argStr.length(); for (int cIdx = 0; cIdx < argStrLength;) { char ch = argStr.charAt(cIdx); char del = ' '; switch (ch) { case '$': final StringBuilder nameBuf = new StringBuilder(); del = argStr.charAt(cIdx + 1); if (del == '{') { cIdx++; for (++cIdx; cIdx < argStr.length(); ++cIdx) { ch = argStr.charAt(cIdx); if (ch == '_' || ch == '.' || ch == '-' || ch == '+' || Character.isLetterOrDigit(ch)) { nameBuf.append(ch); } else { break; } } if (nameBuf.length() >= 0) { String value; final Object temp = vars.get(nameBuf.toString()); if (temp instanceof File) { // for a file we have to fix the separator chars to allow // cross-platform compatibility value = fixFileSeparatorChar(((File) temp).getAbsolutePath()); } else { value = temp != null ? temp.toString() : null; } if (value != null) { argBuf.append(value); } else { if (isLenient) { // just append the unresolved variable declaration argBuf.append("${").append(nameBuf.toString()).append("}"); } else { // complain that no variable was found throw new RuntimeException("No value found for : " + nameBuf); } } del = argStr.charAt(cIdx); if (del != '}') { throw new RuntimeException("Delimiter not found for : " + nameBuf); } } cIdx++; } else { argBuf.append(ch); ++cIdx; } break; default: argBuf.append(ch); ++cIdx; break; } } return argBuf; } /** * Split a string into an array of strings based * on a separator. * * @param input what to split * @param splitChar what to split on * @return the array of strings */ public static String[] split(final String input, final String splitChar) { final StringTokenizer tokens = new StringTokenizer(input, splitChar); final List<String> strList = new ArrayList<String>(); while (tokens.hasMoreTokens()) { strList.add(tokens.nextToken()); } return strList.toArray(new String[strList.size()]); } /** * Fixes the file separator char for the target platform * using the following replacement. * * <ul> * <li>'/' → File.separatorChar</li> * <li>'\\' → File.separatorChar</li> * </ul> * * @param arg the argument to fix * @return the transformed argument */ public static String fixFileSeparatorChar(final String arg) { return arg.replace(SLASH_CHAR, File.separatorChar).replace(BACKSLASH_CHAR, File.separatorChar); } /** * Concatenates an array of string using a separator. * * @param strings the strings to concatenate * @param separator the separator between two strings * @return the concatenated strings */ public static String toString(final String[] strings, final String separator) { final StringBuilder sb = new StringBuilder(); for (int i = 0; i < strings.length; i++) { if (i > 0) { sb.append(separator); } sb.append(strings[i]); } return sb.toString(); } /** * Put quotes around the given String if necessary. * <p> * If the argument doesn't include spaces or quotes, return it as is. If it * contains double quotes, use single quotes - else surround the argument by * double quotes. * </p> * * @param argument the argument to be quoted * @return the quoted argument * @throws IllegalArgumentException If argument contains both types of quotes */ public static String quoteArgument(final String argument) { String cleanedArgument = argument.trim(); // strip the quotes from both ends while (cleanedArgument.startsWith(SINGLE_QUOTE) || cleanedArgument.startsWith(DOUBLE_QUOTE)) { cleanedArgument = cleanedArgument.substring(1); } while (cleanedArgument.endsWith(SINGLE_QUOTE) || cleanedArgument.endsWith(DOUBLE_QUOTE)) { cleanedArgument = cleanedArgument.substring(0, cleanedArgument.length() - 1); } final StringBuilder buf = new StringBuilder(); if (cleanedArgument.indexOf(DOUBLE_QUOTE) > -1) { if (cleanedArgument.indexOf(SINGLE_QUOTE) > -1) { throw new IllegalArgumentException("Can't handle single and double quotes in same argument"); } return buf.append(SINGLE_QUOTE).append(cleanedArgument).append(SINGLE_QUOTE).toString(); } else if (cleanedArgument.indexOf(SINGLE_QUOTE) > -1) { // || cleanedArgument.indexOf(" ") > -1) { return buf.append(DOUBLE_QUOTE).append(cleanedArgument).append(DOUBLE_QUOTE).toString(); } else { return cleanedArgument; } } /** * Determines if this is a quoted argument - either single or * double quoted. * * @param argument the argument to check * @return true when the argument is quoted */ public static boolean isQuoted(final String argument) { return argument.startsWith(SINGLE_QUOTE) && argument.endsWith(SINGLE_QUOTE) || argument.startsWith(DOUBLE_QUOTE) && argument.endsWith(DOUBLE_QUOTE); } }