1   /*
2    * Copyright (C) 2012 The Guava Authors
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    * http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  
17  package com.google.common.base;
18  
19  import com.google.common.annotations.Beta;
20  import com.google.common.annotations.GwtIncompatible;
21  
22  import javax.annotation.Nullable;
23  
24  /**
25   * Represents a {@linkplain System#getProperties() standard system property}.
26   *
27   * @author Kurt Alfred Kluever
28   * @since 15.0
29   */
30  @Beta
31  @GwtIncompatible("java.lang.System#getProperty")
32  public enum StandardSystemProperty {
33  
34    /** Java Runtime Environment version. */
35    JAVA_VERSION("java.version"),
36  
37    /** Java Runtime Environment vendor. */
38    JAVA_VENDOR("java.vendor"),
39  
40    /** Java vendor URL. */
41    JAVA_VENDOR_URL("java.vendor.url"),
42  
43    /** Java installation directory. */
44    JAVA_HOME("java.home"),
45  
46    /** Java Virtual Machine specification version. */
47    JAVA_VM_SPECIFICATION_VERSION("java.vm.specification.version"),
48  
49    /** Java Virtual Machine specification vendor. */
50    JAVA_VM_SPECIFICATION_VENDOR("java.vm.specification.vendor"),
51  
52    /** Java Virtual Machine specification name. */
53    JAVA_VM_SPECIFICATION_NAME("java.vm.specification.name"),
54  
55    /** Java Virtual Machine implementation version. */
56    JAVA_VM_VERSION("java.vm.version"),
57  
58    /** Java Virtual Machine implementation vendor. */
59    JAVA_VM_VENDOR("java.vm.vendor"),
60  
61    /** Java Virtual Machine implementation name. */
62    JAVA_VM_NAME("java.vm.name"),
63  
64    /** Java Runtime Environment specification version. */
65    JAVA_SPECIFICATION_VERSION("java.specification.version"),
66  
67    /** Java Runtime Environment specification vendor. */
68    JAVA_SPECIFICATION_VENDOR("java.specification.vendor"),
69  
70    /** Java Runtime Environment specification name. */
71    JAVA_SPECIFICATION_NAME("java.specification.name"),
72  
73    /** Java class format version number. */
74    JAVA_CLASS_VERSION("java.class.version"),
75  
76    /** Java class path. */
77    JAVA_CLASS_PATH("java.class.path"),
78  
79    /** List of paths to search when loading libraries. */
80    JAVA_LIBRARY_PATH("java.library.path"),
81  
82    /** Default temp file path. */
83    JAVA_IO_TMPDIR("java.io.tmpdir"),
84  
85    /** Name of JIT compiler to use. */
86    JAVA_COMPILER("java.compiler"),
87  
88    /** Path of extension directory or directories. */
89    JAVA_EXT_DIRS("java.ext.dirs"),
90  
91    /** Operating system name. */
92    OS_NAME("os.name"),
93  
94    /** Operating system architecture. */
95    OS_ARCH("os.arch"),
96  
97    /** Operating system version. */
98    OS_VERSION("os.version"),
99  
100   /** File separator ("/" on UNIX). */
101   FILE_SEPARATOR("file.separator"),
102 
103   /** Path separator (":" on UNIX). */
104   PATH_SEPARATOR("path.separator"),
105 
106   /** Line separator ("\n" on UNIX). */
107   LINE_SEPARATOR("line.separator"),
108 
109   /** User's account name. */
110   USER_NAME("user.name"),
111 
112   /** User's home directory. */
113   USER_HOME("user.home"),
114 
115   /** User's current working directory. */
116   USER_DIR("user.dir");
117 
118   private final String key;
119 
120   private StandardSystemProperty(String key) {
121     this.key = key;
122   }
123 
124   /**
125    * Returns the key used to lookup this system property.
126    */
127   public String key() {
128     return key;
129   }
130 
131   /**
132    * Returns the current value for this system property by delegating to
133    * {@link System#getProperty(String)}.
134    */
135   @Nullable
136   public String value() {
137     return System.getProperty(key);
138   }
139 
140   /**
141    * Returns a string representation of this system property.
142    */
143   @Override public String toString() {
144     return key() + "=" + value();
145   }
146 }