Docjar: cvebrowser/dictionary/data/persistence/util/PrepStatementCache.java

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Source code: cvebrowser/dictionary/data/persistence/util/PrepStatementCache.java

1   package cvebrowser.dictionary.data.persistence.util;
2   
3   import java.util.HashMap;
4   import java.util.ResourceBundle;
5   import java.util.Locale;
6   import java.util.Iterator;
7   
8   import java.sql.PreparedStatement;
9   import java.sql.SQLException;
10  
11  import java.io.ObjectOutputStream;
12  import java.io.ObjectInputStream;
13  
14  /**
15   * PrepStatementCache - Specialized cache that stores a set of PreparedStatements for later retrieval.
16   * @author Jose Vicente Nunez Zuleta (josevnz@users.sourceforge.net)
17   * @version 0.1 - 08/17/2003
18   */
19  public final class PrepStatementCache {
20  
21    private static ResourceBundle _bundle = null;
22    // hide the constructor
23    private PrepStatementCache() {};
24    
25    private static PrepStatementCache _instance;
26    
27    private static HashMap _prepMap;
28    
29    /**
30     * Return an instance for this Singleton.
31     * @return PrepStatementCache
32     * @since 0.1
33     */
34    public static synchronized PrepStatementCache getInstance() {
35      if (_instance == null) {
36        _instance = new PrepStatementCache();
37        _prepMap = new HashMap();
38        _bundle = ResourceBundle.getBundle(PrepStatementCache.class.getName(), Locale.getDefault());
39      }
40      return _instance;
41    }
42  
43    /**
44     * Add a element to the cache
45     * @param prep_
46     * @param name_
47     * @throws IllegalArgumentException if any of the arguments is null
48     * @since 0.1
49     */
50    public void put(PreparedStatement prep_, String name_) throws IllegalArgumentException {
51      if (prep_ == null) {
52        throw new IllegalArgumentException(_bundle.getString("cvebrowser.dictionary.data.persistence.util.PrepStatementCache.error.missingParameter") + " 'prep_'");
53      }
54      if (name_ == null) {
55        throw new IllegalArgumentException(_bundle.getString("cvebrowser.dictionary.data.persistence.util.PrepStatementCache.error.missingParameter") + " 'name_'");
56      }
57      _prepMap.put(name_, prep_);
58    }
59    
60    /**
61     * Get the prepared statement back to the caller
62     * @param name_
63     * @return PreparedStatement. Can be null if the prepared statement instance is not registered by that name.
64     * @since 0.1
65     */
66    public PreparedStatement get(String name_) {
67      if (name_ == null) {
68        throw new IllegalArgumentException(_bundle.getString("cvebrowser.dictionary.data.persistence.util.PrepStatementCache.error.missingParameter") + " 'name_'");
69      }
70      return (PreparedStatement) _prepMap.get(name_);
71    }
72    
73    /**
74     * Clean the internal cache. Closes all the opened prepared statements and cleans the cache.
75     */
76    public synchronized void clean() {
77      Iterator iterator = _prepMap.keySet().iterator();
78      while (iterator.hasNext()) {
79        try {
80          PreparedStatement prep = (PreparedStatement) _prepMap.get((String) iterator.next());
81          if (prep != null) {
82            prep.close();
83          }
84        } catch (SQLException ignore) {  };
85      }
86      // clearn the map
87      _prepMap.clear();
88    }
89    
90    /**
91     * Final resource liberation
92     */
93    public void finalize() {
94      clean();
95    }
96    
97    /**
98     * Make this class uncloneable. Anyone who wants to use this class must use the constructor.
99     * @throws CloneNotSupportedException
100    */
101    public final Object clone() throws java.lang.CloneNotSupportedException {
102      throw new java.lang.CloneNotSupportedException();
103    }
104 
105    /**
106    * Make this class unserializable. Any attempt to serialize will throw an exception.
107    * @param out_
108    * @throws IOException
109    */
110    private final void writeObject(ObjectOutputStream out_) throws java.io.IOException {
111      throw new java.io.IOException();
112    }
113    
114    /**
115    * Make this class undeserializeable. Throw an exception if this method is ever called.
116    * @param in_
117    * @throws IOException
118    */
119    private final void readObject(ObjectInputStream in_) throws java.io.IOException {
120      throw new java.io.IOException();
121    }
122 }