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Java > Open Source Codes > org > apache > cayenne > project > CayenneUserDir


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19
20 package org.apache.cayenne.project;
21
22 import java.io.File JavaDoc;
23
24 /**
25  * CayenneUserDir represents a directory where all Cayenne-related information
26  * is stored on the user machine. This is normally a <code>$HOME/.cayenne</code>
27  * directory.
28  *
29  * @author Andrus Adamchik
30  */
31 public class CayenneUserDir {
32
33     protected static CayenneUserDir sharedInstance;
34
35     public static final String JavaDoc CAYENNE_DIR = ".cayenne";
36     
37     /**
38      * A property name for the property that allows to define an alternative
39      * location of Cayenne User Directory (instead of default "$HOME/.cayenne").
40      *
41      * @since 1.1
42      */
43     public static final String JavaDoc ALT_USER_DIR_PROPERTY = "cayenne.userdir";
44
45     protected File JavaDoc cayenneUserDir;
46
47     public static CayenneUserDir getInstance() {
48         if(sharedInstance == null) {
49             sharedInstance = new CayenneUserDir();
50         }
51         return sharedInstance;
52     }
53     
54     
55     /**
56      * Constructor for CayenneUserDir.
57      */
58     protected CayenneUserDir() {
59         super();
60
61         File JavaDoc tmpDir = null;
62         String JavaDoc dirName = System.getProperty(ALT_USER_DIR_PROPERTY);
63
64         if (dirName != null) {
65             tmpDir = new File JavaDoc(dirName);
66         }
67         else {
68             File JavaDoc homeDir = new File JavaDoc(System.getProperty("user.home"));
69             tmpDir = new File JavaDoc(homeDir, CAYENNE_DIR);
70         }
71
72         if (tmpDir.exists() && !tmpDir.isDirectory()) {
73             tmpDir = null;
74         }
75         else if (tmpDir.exists() && !tmpDir.canRead()) {
76             tmpDir = null;
77         }
78         else if (!tmpDir.exists()) {
79             tmpDir.mkdirs();
80             if (!tmpDir.exists()) {
81                 tmpDir = null;
82             }
83         }
84
85         cayenneUserDir = tmpDir;
86     }
87
88     /**
89      * Returns a directory object where all user Cayenne-related configuration is stored.
90      * May return null if the directory is not accessible for whatever reason.
91      */
92     public File JavaDoc getDirectory() {
93         return cayenneUserDir;
94     }
95     
96     /**
97      * Return false if the directory is not accessible for
98      * any reason at least for reading.
99      */
100     public boolean canRead() {
101         return cayenneUserDir != null;
102     }
103     
104     /**
105      * Return false if the directory is not accessible for
106      * any reason at least for reading.
107      */
108     public boolean canWrite() {
109         return cayenneUserDir != null && cayenneUserDir.canWrite();
110     }
111     
112     public File JavaDoc resolveFile(String JavaDoc name) {
113         return new File JavaDoc(cayenneUserDir, name);
114     }
115 }
116
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