001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 *
017 */
018
019 package org.apache.commons.exec.environment;
020
021 import java.io.IOException;
022 import java.util.Iterator;
023 import java.util.Map;
024
025 import org.apache.commons.exec.OS;
026
027 /**
028 * Wrapper for environment variables.
029 */
030 public class EnvironmentUtils
031 {
032
033 private static final DefaultProcessingEnvironment procEnvironment;
034
035 static {
036 if (OS.isFamilyOpenVms()) {
037 procEnvironment = new OpenVmsProcessingEnvironment();
038 } else {
039 procEnvironment = new DefaultProcessingEnvironment();
040 }
041 }
042
043 /**
044 * Disable constructor.
045 */
046 private EnvironmentUtils() {
047
048 }
049
050 /**
051 * Get the variable list as an array.
052 *
053 * @param environment the environment to use, may be <code>null</code>
054 * @return array of key=value assignment strings or <code>null</code> if and only if
055 * the input map was <code>null</code>
056 */
057 public static String[] toStrings(Map environment) {
058 if (environment == null) {
059 return null;
060 }
061 String[] result = new String[environment.size()];
062 int i = 0;
063 for (Iterator iter = environment.entrySet().iterator(); iter.hasNext();) {
064 Map.Entry entry = (Map.Entry) iter.next();
065
066 result[i] = entry.getKey().toString() + "=" + entry.getValue().toString();
067 i++;
068 }
069 return result;
070 }
071
072 /**
073 * Find the list of environment variables for this process. The returned map preserves
074 * the casing of a variable's name on all platforms but obeys the casing rules of the
075 * current platform during lookup, e.g. key names will be case-insensitive on Windows
076 * platforms.
077 *
078 * @return a map containing the environment variables, may be empty but never <code>null</code>
079 * @throws IOException the operation failed
080 */
081 public static Map getProcEnvironment() throws IOException {
082 return procEnvironment.getProcEnvironment();
083 }
084
085 /**
086 * Add a key/value pair to the given environment.
087 * If the key matches an existing key, the previous setting is replaced.
088 *
089 * @param environment the current environment
090 * @param keyAndValue the key/value pair
091 */
092 public static void addVariableToEnvironment(Map environment, String keyAndValue) {
093 String[] parsedVariable = parseEnvironmentVariable(keyAndValue);
094 environment.put(parsedVariable[0], parsedVariable[1]);
095 }
096
097 /**
098 * Split a key/value pair into a String[]. It is assumed
099 * that the ky/value pair contains a '=' character.
100 *
101 * @param keyAndValue the key/value pair
102 * @return a String[] containing the key and value
103 */
104 private static String[] parseEnvironmentVariable(final String keyAndValue) {
105 int index = keyAndValue.indexOf('=');
106 if (index == -1) {
107 throw new IllegalArgumentException(
108 "Environment variable for this platform "
109 + "must contain an equals sign ('=')");
110 }
111
112 String[] result = new String[2];
113 result[0] = keyAndValue.substring(0, index);
114 result[1] = keyAndValue.substring(index + 1);
115
116 return result;
117 }
118
119 }