1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.exec.environment;
19
20 import java.io.IOException;
21 import java.util.Map;
22 import java.util.Objects;
23
24 /**
25 * Wraps environment variables.
26 */
27 public class EnvironmentUtils {
28
29 private static final DefaultProcessingEnvironment ENVIRONMENT;
30
31 static {
32 ENVIRONMENT = new DefaultProcessingEnvironment();
33 }
34
35 /**
36 * Adds a key/value pair to the given environment. If the key matches an existing key, the previous setting is replaced.
37 *
38 * @param environment the current environment.
39 * @param keyAndValue the key/value pair.
40 */
41 public static void addVariableToEnvironment(final Map<String, String> environment, final String keyAndValue) {
42 final String[] parsedVariable = parseEnvironmentVariable(keyAndValue);
43 environment.put(parsedVariable[0], parsedVariable[1]);
44 }
45
46 /**
47 * Gets the list of environment variables for this process. The returned map preserves the casing of a variable's name on all platforms but obeys the casing
48 * rules of the current platform during lookup, e.g. key names will be case-insensitive on Windows platforms.
49 *
50 * @return a map containing the environment variables, may be empty but never {@code null}.
51 * @throws IOException the operation failed.
52 */
53 public static Map<String, String> getProcEnvironment() throws IOException {
54 return ENVIRONMENT.getProcEnvironment();
55 }
56
57 /**
58 * Parses a key/value pair into a String[]. It is assumed that the ky/value pair contains a '=' character.
59 *
60 * @param keyAndValue the key/value pair.
61 * @return a String[] containing the key and value.
62 */
63 private static String[] parseEnvironmentVariable(final String keyAndValue) {
64 final int index = keyAndValue.indexOf('=');
65 if (index == -1) {
66 throw new IllegalArgumentException("Environment variable for this platform must contain an equals sign ('=')");
67 }
68 final String[] result = new String[2];
69 result[0] = keyAndValue.substring(0, index);
70 result[1] = keyAndValue.substring(index + 1);
71 return result;
72 }
73
74 private static String toString(final String value) {
75 return Objects.toString(value, "");
76 }
77
78 /**
79 * Converts a variable map as an array.
80 *
81 * @param environment the environment to use, may be {@code null}.
82 * @return array of key=value assignment strings or {@code null} if and only if the input map was {@code null}.
83 */
84 public static String[] toStrings(final Map<String, String> environment) {
85 if (environment == null) {
86 return null;
87 }
88 return environment.entrySet().stream().map(e -> toString(e.getKey()) + "=" + toString(e.getValue())).toArray(String[]::new);
89 }
90
91 /**
92 * Hides constructor.
93 */
94 private EnvironmentUtils() {
95 // empty
96 }
97
98 }