KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > com > db4o > cs > messages > MQueryExecute


1 /* Copyright (C) 2004 - 2006 db4objects Inc. http://www.db4o.com
2
3 This file is part of the db4o open source object database.
4
5 db4o is free software; you can redistribute it and/or modify it under
6 the terms of version 2 of the GNU General Public License as published
7 by the Free Software Foundation and as clarified by db4objects' GPL
8 interpretation policy, available at
9 http://www.db4o.com/about/company/legalpolicies/gplinterpretation/
10 Alternatively you can write to db4objects, Inc., 1900 S Norfolk Street,
11 Suite 350, San Mateo, CA 94403, USA.
12
13 db4o is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 for more details.
17
18 You should have received a copy of the GNU General Public License along
19 with this program; if not, write to the Free Software Foundation, Inc.,
20 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
21 package com.db4o.cs.messages;
22
23 import com.db4o.*;
24 import com.db4o.config.*;
25 import com.db4o.cs.*;
26 import com.db4o.inside.query.*;
27
28 public final class MQueryExecute extends MsgQuery {
29     
30     private QueryEvaluationMode _evaluationMode;
31     
32     public boolean processAtServer(YapServerThread serverThread) {
33         unmarshall();
34         writeQueryResult(execute(), serverThread, _evaluationMode);
35         return true;
36     }
37
38     private AbstractQueryResult execute() {
39         
40         synchronized (streamLock()) {
41             
42             // TODO: The following used to run outside of the
43 // synchronisation block for better performance but
44 // produced inconsistent results, cause unknown.
45
46             QQuery query = (QQuery) stream().unmarshall(_payLoad);
47             query.unmarshall(transaction());
48             
49             _evaluationMode = query.evaluationMode();
50             
51             return executeFully(query);
52             
53         }
54     }
55
56     private AbstractQueryResult executeFully(QQuery query) {
57         try {
58             AbstractQueryResult qr = newQueryResult(query.evaluationMode());
59             qr.loadFromQuery(query);
60             return qr;
61         } catch (Exception JavaDoc e) {
62             return newQueryResult(query.evaluationMode());
63         }
64     }
65     
66 }
Popular Tags