KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > org > objectstyle > cayenne > service > ObjectDataContextSelectAction


1 /* ====================================================================
2  *
3  * The ObjectStyle Group Software License, version 1.1
4  * ObjectStyle Group - http://objectstyle.org/
5  *
6  * Copyright (c) 2002-2005, Andrei (Andrus) Adamchik and individual authors
7  * of the software. All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  *
13  * 1. Redistributions of source code must retain the above copyright
14  * notice, this list of conditions and the following disclaimer.
15  *
16  * 2. Redistributions in binary form must reproduce the above copyright
17  * notice, this list of conditions and the following disclaimer in
18  * the documentation and/or other materials provided with the
19  * distribution.
20  *
21  * 3. The end-user documentation included with the redistribution, if any,
22  * must include the following acknowlegement:
23  * "This product includes software developed by independent contributors
24  * and hosted on ObjectStyle Group web site (http://objectstyle.org/)."
25  * Alternately, this acknowlegement may appear in the software itself,
26  * if and wherever such third-party acknowlegements normally appear.
27  *
28  * 4. The names "ObjectStyle Group" and "Cayenne" must not be used to endorse
29  * or promote products derived from this software without prior written
30  * permission. For written permission, email
31  * "andrus at objectstyle dot org".
32  *
33  * 5. Products derived from this software may not be called "ObjectStyle"
34  * or "Cayenne", nor may "ObjectStyle" or "Cayenne" appear in their
35  * names without prior written permission.
36  *
37  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
38  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
39  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
40  * DISCLAIMED. IN NO EVENT SHALL THE OBJECTSTYLE GROUP OR
41  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
42  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
43  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
44  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
45  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
46  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
47  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
48  * SUCH DAMAGE.
49  * ====================================================================
50  *
51  * This software consists of voluntary contributions made by many
52  * individuals and hosted on ObjectStyle Group web site. For more
53  * information on the ObjectStyle Group, please see
54  * <http://objectstyle.org/>.
55  */
56 package org.objectstyle.cayenne.service;
57
58 import java.util.List JavaDoc;
59
60 import org.objectstyle.cayenne.CayenneRuntimeException;
61 import org.objectstyle.cayenne.ObjectFactory;
62 import org.objectstyle.cayenne.access.DataContextObjectFactory;
63 import org.objectstyle.cayenne.access.IncrementalFaultList;
64 import org.objectstyle.cayenne.access.util.SelectObserver;
65 import org.objectstyle.cayenne.map.ObjEntity;
66 import org.objectstyle.cayenne.query.GenericSelectQuery;
67 import org.objectstyle.cayenne.query.Query;
68 import org.objectstyle.cayenne.query.QueryExecutionPlan;
69
70 /**
71  * Executes non-selecting queries on behalf of DataDomain.
72  *
73  * @since 1.2
74  * @author Andrus Adamchik
75  */
76 // Differences with DataContextSelectAction:
77 // * shared cache handling is delegated to the underlying PersistenceContext.
78 class ObjectDataContextSelectAction {
79
80     ObjectDataContext context;
81
82     ObjectDataContextSelectAction(ObjectDataContext context) {
83         this.context = context;
84     }
85
86     List JavaDoc performQuery(QueryExecutionPlan queryPlan) {
87         GenericSelectQuery selectQuery = resolveQuery(queryPlan);
88
89         // check if result pagination is requested
90 // let a list handle fetch in this case
91 if (selectQuery.getPageSize() > 0) {
92             return new IncrementalFaultList(context, selectQuery);
93         }
94
95         String JavaDoc cacheKey = selectQuery.getName();
96         boolean cacheResults = GenericSelectQuery.LOCAL_CACHE.equals(selectQuery
97                 .getCachePolicy());
98
99         // get results from cache...
100 if (cacheResults) {
101
102             // sanity check
103 if (cacheKey == null) {
104                 throw new CayenneRuntimeException(
105                         "Caching of unnamed queries is not supported.");
106             }
107
108             // results should have been stored as rows or objects when
109 // they were originally cached... do no conversions now
110 List JavaDoc results = context.getObjectStore().getCachedQueryResult(cacheKey);
111             if (results != null) {
112                 return results;
113             }
114         }
115
116         // must fetch...
117 SelectObserver observer = new SelectObserver(selectQuery.getLoggingLevel());
118         context.getParentContext().performQuery(selectQuery, observer);
119
120         List JavaDoc results;
121
122         if (selectQuery.isFetchingDataRows()) {
123             results = observer.getResults(selectQuery);
124         }
125         else {
126             ObjectFactory factory = new DataContextObjectFactory(context, selectQuery
127                     .isRefreshingObjects(), selectQuery.isResolvingInherited());
128             ObjEntity rootEntity = context.getEntityResolver().lookupObjEntity(
129                     selectQuery);
130             results = observer.getResultsAsObjects(factory, rootEntity, selectQuery);
131         }
132
133         // cache results if needed
134 if (cacheResults) {
135             context.getObjectStore().cacheQueryResult(cacheKey, results);
136         }
137
138         return results;
139     }
140
141     /**
142      * Executes query resolving phase...
143      */
144     GenericSelectQuery resolveQuery(QueryExecutionPlan queryPlan) {
145         Query resolved = queryPlan.resolve(context.getEntityResolver());
146
147         if (!(resolved instanceof GenericSelectQuery)) {
148             throw new CayenneRuntimeException(
149                     "QueryExecutionPlan was resolved to a query that is not a GenericSelectQuery: "
150                             + resolved);
151         }
152
153         return (GenericSelectQuery) resolved;
154     }
155 }
156
Popular Tags