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Java > Open Source Codes > org > objectstyle > cayenne > access > jdbc > SelectAction


1 /* ====================================================================
2  *
3  * The ObjectStyle Group Software License, version 1.1
4  * ObjectStyle Group - http://objectstyle.org/
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6  * Copyright (c) 2002-2005, Andrei (Andrus) Adamchik and individual authors
7  * of the software. All rights reserved.
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56 package org.objectstyle.cayenne.access.jdbc;
57
58 import java.sql.Connection JavaDoc;
59 import java.sql.PreparedStatement JavaDoc;
60 import java.sql.ResultSet JavaDoc;
61 import java.sql.SQLException JavaDoc;
62 import java.util.List JavaDoc;
63
64 import org.objectstyle.cayenne.access.OperationObserver;
65 import org.objectstyle.cayenne.access.QueryLogger;
66 import org.objectstyle.cayenne.access.ResultIterator;
67 import org.objectstyle.cayenne.access.trans.SelectTranslator;
68 import org.objectstyle.cayenne.access.util.DistinctResultIterator;
69 import org.objectstyle.cayenne.dba.DbAdapter;
70 import org.objectstyle.cayenne.map.EntityResolver;
71 import org.objectstyle.cayenne.query.SelectQuery;
72
73 /**
74  * A SQLAction that handles SelectQuery execution.
75  *
76  * @since 1.2
77  * @author Andrei Adamchik
78  */
79 public class SelectAction extends BaseSQLAction {
80
81     protected SelectQuery query;
82
83     public SelectAction(SelectQuery query, DbAdapter adapter,
84             EntityResolver entityResolver) {
85         super(adapter, entityResolver);
86         this.query = query;
87     }
88
89     protected SelectTranslator createTranslator(Connection JavaDoc connection) {
90         SelectTranslator translator = new SelectTranslator();
91         translator.setQuery(query);
92         translator.setAdapter(adapter);
93         translator.setEntityResolver(getEntityResolver());
94         translator.setConnection(connection);
95         return translator;
96     }
97
98     public void performAction(Connection JavaDoc connection, OperationObserver observer)
99             throws SQLException JavaDoc, Exception JavaDoc {
100
101         long t1 = System.currentTimeMillis();
102
103         SelectTranslator translator = createTranslator(connection);
104         PreparedStatement JavaDoc prepStmt = translator.createStatement(query.getLoggingLevel());
105         ResultSet JavaDoc rs = prepStmt.executeQuery();
106
107         RowDescriptor descriptor = new RowDescriptor(
108                 translator.getResultColumns(),
109                 getAdapter().getExtendedTypes());
110         JDBCResultIterator workerIterator = new JDBCResultIterator(
111                 connection,
112                 prepStmt,
113                 rs,
114                 descriptor,
115                 query.getFetchLimit());
116
117         ResultIterator it = workerIterator;
118
119         // wrap result iterator if distinct has to be suppressed
120 if (translator.isSuppressingDistinct()) {
121             it = new DistinctResultIterator(workerIterator, translator.getRootDbEntity());
122         }
123
124         // TODO: Should do something about closing ResultSet and PreparedStatement in this
125 // method, instead of relying on DefaultResultIterator to do that later
126
127         if (!observer.isIteratedResult()) {
128             // note that we don't need to close ResultIterator
129 // since "dataRows" will do it internally
130 List JavaDoc resultRows = it.dataRows(true);
131             QueryLogger.logSelectCount(query.getLoggingLevel(), resultRows.size(), System
132                     .currentTimeMillis()
133                     - t1);
134
135             observer.nextDataRows(query, resultRows);
136         }
137         else {
138             try {
139                 workerIterator.setClosingConnection(true);
140                 observer.nextDataRows(translator.getQuery(), it);
141             }
142             catch (Exception JavaDoc ex) {
143                 it.close();
144                 throw ex;
145             }
146         }
147     }
148 }
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