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.daemon.support;
19
20 import java.io.FileInputStream;
21 import java.io.IOException;
22 import java.io.InputStream;
23 import java.util.ArrayList;
24 import java.util.Properties;
25 import java.text.ParseException;
26
27 /**
28 * Used by jsvc for Daemon configuration.
29 * <p>
30 * Configuration is read from properties file.
31 * If no properties file is given the {@code daemon.properties}
32 * is used from the current directory.
33 * </p>
34 * <p>
35 * The properties file can have property values expanded at runtime
36 * by using System properties or execution environment. The part
37 * of the property value between {@code ${} and {@code }}
38 * will be used as System property or environment key. If found then
39 * the entire {@code ${foo}} will be replaced by the value of
40 * either system property or environment variable named {@code foo}.
41 * </p>
42 * <p>
43 * If no variable is found the {@code ${foo}} will be passed as is.
44 * In case of {@code $${foo}} this will be unescaped and resulting
45 * value will be {@code ${foo}}.
46 * </p>
47 */
48 public final class DaemonConfiguration
49 {
50 /**
51 * Default configuration file name.
52 */
53 protected final static String DEFAULT_CONFIG = "daemon.properties";
54 /**
55 * Property prefix
56 */
57 protected final static String PREFIX = "daemon.";
58 private final static String BTOKEN = "${";
59 private final static String ETOKEN = "}";
60
61
62 private final Properties configurationProperties;
63 private final Properties systemProperties;
64
65 /**
66 * An empty immutable {@code String} array.
67 */
68 static final String[] EMPTY_STRING_ARRAY = {};
69
70 /**
71 * Default constructor
72 */
73 public DaemonConfiguration()
74 {
75 configurationProperties = new Properties();
76 systemProperties = System.getProperties();
77 }
78
79 /**
80 * Loads the configuration properties file.
81 *
82 * @param fileName The properties file to load.
83 * @return {@code true} if the file was loaded.
84 */
85 public boolean load(String fileName)
86 {
87 if (fileName == null) {
88 fileName = DEFAULT_CONFIG;
89 }
90
91 try (InputStream inputStream = new FileInputStream(fileName)) {
92 configurationProperties.clear();
93 configurationProperties.load(inputStream);
94 return true;
95 } catch (final IOException ex) {
96 // Error reading properties file
97 return false;
98 }
99 }
100
101 private String expandProperty(final String propValue)
102 throws ParseException
103 {
104 final StringBuilder expanded;
105 int btoken;
106 int ctoken = 0;
107
108 if (propValue == null) {
109 return null;
110 }
111 expanded = new StringBuilder();
112 btoken = propValue.indexOf(BTOKEN);
113 while (btoken != -1) {
114 if (btoken > 0 && propValue.charAt(btoken - 1) == BTOKEN.charAt(0)) {
115 // Skip and unquote.
116 expanded.append(propValue.substring(ctoken, btoken));
117 ctoken = btoken + 1;
118 btoken = propValue.indexOf(BTOKEN, btoken + BTOKEN.length());
119 continue;
120 }
121 final int etoken = propValue.indexOf(ETOKEN, btoken);
122 if (etoken == -1) {
123 // We have "${" without "}"
124 throw new ParseException("Error while looking for teminating '" +
125 ETOKEN + "'", btoken);
126 }
127 final String variable = propValue.substring(btoken + BTOKEN.length(), etoken);
128 String sysvalue = systemProperties.getProperty(variable);
129 if (sysvalue == null) {
130 // Try with the environment if there was no
131 // property by that name.
132 sysvalue = System.getenv(variable);
133 }
134 if (sysvalue != null) {
135 final String strtoken = propValue.substring(ctoken, btoken);
136 expanded.append(strtoken);
137 expanded.append(sysvalue);
138 ctoken = etoken + ETOKEN.length();
139 }
140 btoken = propValue.indexOf(BTOKEN, etoken + ETOKEN.length());
141 }
142 // Add what's left.
143 expanded.append(propValue.substring(ctoken));
144 return expanded.toString();
145 }
146
147 /**
148 * Gets the configuration property.
149 *
150 * @param name The name of the property to get.
151 *
152 * @throws ParseException if the property is wrongly formatted.
153 *
154 * @return Configuration property including any expansion/replacement
155 */
156 public String getProperty(final String name)
157 throws ParseException
158 {
159 if (name == null) {
160 return null;
161 }
162 return expandProperty(configurationProperties.getProperty(PREFIX + name));
163 }
164
165 /**
166 * Gets the configuration property array.
167 * <p>
168 * Property array is constructed form the list of properties
169 * which end with {@code [index]}
170 * </p>
171 * <pre>
172 * daemon.arg[0] = argument 1
173 * daemon.arg[1] = argument 2
174 * daemon.arg[2] = argument 3
175 * </pre>
176 * @param name The name of the property array to get.
177 *
178 * @throws ParseException if the property is wrongly formatted.
179 *
180 * @return Configuration property array including any expansion/replacement
181 */
182 public String[] getPropertyArray(final String name)
183 throws ParseException
184 {
185 final ArrayList<String> list = new ArrayList<>();
186 String args;
187
188 // Load daemon.arg[0] ... daemon.arg[n] into the String array.
189 //
190 while ((args = getProperty(name + "[" + list.size() + "]")) != null) {
191 list.add(args);
192 }
193 return list.toArray(EMPTY_STRING_ARRAY);
194 }
195 }
196