KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > com > quadcap > sql > lock > TransactionPool


1 package com.quadcap.sql.lock;
2
3 /* Copyright 1999 - 2003 Quadcap Software. All rights reserved.
4  *
5  * This software is distributed under the Quadcap Free Software License.
6  * This software may be used or modified for any purpose, personal or
7  * commercial. Open Source redistributions are permitted. Commercial
8  * redistribution of larger works derived from, or works which bundle
9  * this software requires a "Commercial Redistribution License"; see
10  * http://www.quadcap.com/purchase.
11  *
12  * Redistributions qualify as "Open Source" under one of the following terms:
13  *
14  * Redistributions are made at no charge beyond the reasonable cost of
15  * materials and delivery.
16  *
17  * Redistributions are accompanied by a copy of the Source Code or by an
18  * irrevocable offer to provide a copy of the Source Code for up to three
19  * years at the cost of materials and delivery. Such redistributions
20  * must allow further use, modification, and redistribution of the Source
21  * Code under substantially the same terms as this license.
22  *
23  * Redistributions of source code must retain the copyright notices as they
24  * appear in each source code file, these license terms, and the
25  * disclaimer/limitation of liability set forth as paragraph 6 below.
26  *
27  * Redistributions in binary form must reproduce this Copyright Notice,
28  * these license terms, and the disclaimer/limitation of liability set
29  * forth as paragraph 6 below, in the documentation and/or other materials
30  * provided with the distribution.
31  *
32  * The Software is provided on an "AS IS" basis. No warranty is
33  * provided that the Software is free of defects, or fit for a
34  * particular purpose.
35  *
36  * Limitation of Liability. Quadcap Software shall not be liable
37  * for any damages suffered by the Licensee or any third party resulting
38  * from use of the Software.
39  */
40
41 import com.quadcap.util.collections.LongMap;
42
43 import com.quadcap.util.Debug;
44 import com.quadcap.util.Util;
45
46 /**
47  * A pool for transactions, to reduce gc thrashing
48  *
49  * @author Stan Bailes
50  */
51 public class TransactionPool extends ObjectPool {
52     /**
53      * Keep active transactions in this map
54      */
55     LongMap map = new LongMap(13);
56     
57     /**
58      * Create and initialize the pool
59      */
60     public TransactionPool() {
61         super(new Transaction());
62     }
63
64     /**
65      * Get a new transaction from the pool
66      */
67     public PooledObject get(long transId) {
68         Transaction trans = (Transaction)map.get(transId);
69         if (trans == null) {
70             trans = (Transaction)(super.get());
71             trans.init(transId);
72             map.put(transId, trans);
73         }
74         return trans;
75     }
76
77     /**
78      * Find an existing transaction. Return null if the specified
79      * transaction doesn't exist.
80      */
81     public Transaction find(long transId) {
82         return (Transaction)map.get(transId);
83     }
84
85     /**
86      * Return this transaction to the pool
87      */
88     public void release(Transaction t) {
89         map.remove(t.transactionId);
90         t.wait = null;
91         super.release(t);
92     }
93 }
94
Popular Tags