Source code: org/objectstyle/cayenne/access/util/SelectObserver.java
1 /* ====================================================================
2 *
3 * The ObjectStyle Group Software License, Version 1.0
4 *
5 * Copyright (c) 2002-2003 The ObjectStyle Group
6 * and individual authors of the software. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
18 * distribution.
19 *
20 * 3. The end-user documentation included with the redistribution, if
21 * any, must include the following acknowlegement:
22 * "This product includes software developed by the
23 * ObjectStyle Group (http://objectstyle.org/)."
24 * Alternately, this acknowlegement may appear in the software itself,
25 * if and wherever such third-party acknowlegements normally appear.
26 *
27 * 4. The names "ObjectStyle Group" and "Cayenne"
28 * must not be used to endorse or promote products derived
29 * from this software without prior written permission. For written
30 * permission, please contact andrus@objectstyle.org.
31 *
32 * 5. Products derived from this software may not be called "ObjectStyle"
33 * nor may "ObjectStyle" appear in their names without prior written
34 * permission of the ObjectStyle Group.
35 *
36 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
37 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
38 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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42 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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46 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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48 * ====================================================================
49 *
50 * This software consists of voluntary contributions made by many
51 * individuals on behalf of the ObjectStyle Group. For more
52 * information on the ObjectStyle Group, please see
53 * <http://objectstyle.org/>.
54 *
55 */
56
57 package org.objectstyle.cayenne.access.util;
58
59 import java.util.HashMap;
60 import java.util.List;
61 import java.util.Map;
62
63 import org.apache.log4j.Level;
64 import org.objectstyle.cayenne.CayenneRuntimeException;
65 import org.objectstyle.cayenne.query.Query;
66 import org.objectstyle.cayenne.util.Util;
67
68 /**
69 * OperationObserver that accumulates select query results provided
70 * by callback methods. Later the results can be retrieved
71 * via different <code>getResults</code> methods.
72 *
73 * <p>This class can serve as a helper for classes that work with
74 * DataNode directly, bypassing DataContext. Also it is used by DataContext
75 * to implement "data rows" functionality - retrieving data without
76 * instantiating and registering DataObjects.
77 * </p>
78 *
79 * <p>If exceptions happen during the execution, they are immediately rethrown.
80 * </p>
81 *
82 * <p><i>For more information see <a href="../../../../../../userguide/index.html"
83 * target="_top">Cayenne User Guide.</a></i></p>
84 *
85 * @author Andrei Adamchik
86 */
87 public class SelectObserver extends DefaultOperationObserver {
88 protected Map results = new HashMap();
89 protected int selectCount;
90
91 public SelectObserver() {}
92
93 public SelectObserver(Level logLevel) {
94 super.setLoggingLevel(logLevel);
95 }
96
97 /**
98 * Returns a count of select queries that returned results
99 * since the last time "clear" was called, or since this object
100 * was created.
101 */
102 public int getSelectCount() {
103 return selectCount;
104 }
105
106 /**
107 * Returns a list of result snapshots for the specified query,
108 * or null if this query has never produced any results.
109 */
110 public List getResults(Query q) {
111 return (List) results.get(q);
112 }
113
114 /**
115 * Returns query results accumulated during query execution with this
116 * object as an operation observer.
117 */
118 public Map getResults() {
119 return results;
120 }
121
122 /** Clears fetched objects stored in an internal list. */
123 public void clear() {
124 selectCount = 0;
125 results.clear();
126 }
127
128 /**
129 * Stores all objects in <code>dataRows</code> in an internal
130 * result list.
131 */
132 public void nextDataRows(Query query, List dataRows) {
133 super.nextDataRows(query, dataRows);
134 if (dataRows != null) {
135 results.put(query, dataRows);
136 }
137
138 selectCount++;
139 }
140
141 /**
142 * Overrides superclass implementation to rethrow an exception
143 * immediately.
144 */
145 public void nextQueryException(Query query, Exception ex) {
146 super.nextQueryException(query, ex);
147 throw new CayenneRuntimeException("Query exception.", Util.unwindException(ex));
148 }
149
150 /**
151 * Overrides superclass implementation to rethrow an exception
152 * immediately.
153 */
154 public void nextGlobalException(Exception ex) {
155 super.nextGlobalException(ex);
156 throw new CayenneRuntimeException("Global exception.", Util.unwindException(ex));
157 }
158 }