001: /*
002: * ====================================================================
003: * JAFFA - Java Application Framework For All
004: *
005: * Copyright (C) 2002 JAFFA Development Group
006: *
007: * This library is free software; you can redistribute it and/or
008: * modify it under the terms of the GNU Lesser General Public
009: * License as published by the Free Software Foundation; either
010: * version 2.1 of the License, or (at your option) any later version.
011: *
012: * This library is distributed in the hope that it will be useful,
013: * but WITHOUT ANY WARRANTY; without even the implied warranty of
014: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
015: * Lesser General Public License for more details.
016: *
017: * You should have received a copy of the GNU Lesser General Public
018: * License along with this library; if not, write to the Free Software
019: * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
020: *
021: * Redistribution and use of this software and associated documentation ("Software"),
022: * with or without modification, are permitted provided that the following conditions are met:
023: * 1. Redistributions of source code must retain copyright statements and notices.
024: * Redistributions must also contain a copy of this document.
025: * 2. Redistributions in binary form must reproduce the above copyright notice,
026: * this list of conditions and the following disclaimer in the documentation
027: * and/or other materials provided with the distribution.
028: * 3. The name "JAFFA" must not be used to endorse or promote products derived from
029: * this Software without prior written permission. For written permission,
030: * please contact mail to: jaffagroup@yahoo.com.
031: * 4. Products derived from this Software may not be called "JAFFA" nor may "JAFFA"
032: * appear in their names without prior written permission.
033: * 5. Due credit should be given to the JAFFA Project (http://jaffa.sourceforge.net).
034: *
035: * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESSED OR IMPLIED
036: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
037: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
038: * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
039: * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
040: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
041: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
042: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
043: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
044: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
045: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
046: * SUCH DAMAGE.
047: * ====================================================================
048: */
049:
050: package org.jaffa.persistence.engines.jdbcengine.interceptor;
051:
052: import java.util.*;
053: import org.apache.log4j.Logger;
054: import org.jaffa.persistence.engines.jdbcengine.datasource.PersistentTransaction;
055: import org.jaffa.persistence.engines.jdbcengine.querygenerator.JdbcBridge;
056: import org.jaffa.persistence.Criteria;
057: import org.jaffa.persistence.engines.jdbcengine.IStoredProcedure;
058: import org.jaffa.persistence.exceptions.UOWException;
059: import org.jaffa.persistence.exceptions.QueryFailedException;
060:
061: /** This is the Interceptor which queries the database.
062: */
063: public class QueryInterceptor extends AbstractInterceptor {
064:
065: private static final Logger log = Logger
066: .getLogger(QueryInterceptor.class);
067:
068: /**Performs the logic associated with querying the database. It will perform queries for each Criteria object in the PersistentTransaction's QUERY collection.
069: * Ideally there will be just one Criteria object in the collection.
070: * Control will be passed to the next interceptor in the chain, if any, else a Collection will be returned containing the Results of the last query.
071: * @param pt The PersistentTransaction object, on which the Interceptor is to be executed.
072: * @throws UOWException if any error occurs.
073: * @return the output from the next Interceptor in the chain, if any, else a Collection will be returned containing the Results of the last query. However, for a Criteria having a StoredProcedure, the output will be null.
074: */
075: public Object invoke(PersistentTransaction pt) throws UOWException {
076: Object output = null;
077: Collection objects = pt.getQueries();
078: if (objects != null) {
079: for (Iterator i = objects.iterator(); i.hasNext();) {
080: Criteria object = (Criteria) i.next();
081:
082: // check if the 1st entry in the criteria is a StoredPreocdure
083: Object firstCriteriaElement = null;
084: Collection criteriaEntries = object
085: .getCriteriaEntries();
086: if (criteriaEntries != null
087: && criteriaEntries.size() > 0)
088: firstCriteriaElement = object.getCriteriaEntries()
089: .iterator().next();
090: if (firstCriteriaElement != null)
091: firstCriteriaElement = ((Criteria.CriteriaEntry) firstCriteriaElement)
092: .getValue();
093: if (firstCriteriaElement != null
094: && firstCriteriaElement instanceof IStoredProcedure) {
095: try {
096: if (log.isDebugEnabled())
097: log
098: .debug("Invoking JdbcBridge.executeStoredProcedure()");
099: JdbcBridge
100: .executeStoredProcedure(
101: (IStoredProcedure) firstCriteriaElement,
102: pt.getDataSource());
103: } catch (Exception e) {
104: i.remove();
105: String str = "Error in executing the StoredProcedure: "
106: + firstCriteriaElement;
107: log.error(str, e);
108: throw new QueryFailedException(null, e);
109: }
110: } else {
111: try {
112: if (log.isDebugEnabled())
113: log
114: .debug("Invoking JdbcBridge.executeQuery()");
115: output = JdbcBridge.executeQuery(object, pt
116: .getDataSource());
117: } catch (Exception e) {
118: i.remove();
119: String str = "Error in executing the query on : "
120: + object.getTable();
121: log.error(str, e);
122: throw new QueryFailedException(null, e);
123: }
124: }
125:
126: i.remove();
127: }
128: }
129:
130: // pass control to the next interceptor in the chain
131: if (getNextInterceptor() != null) {
132: if (log.isDebugEnabled())
133: log.debug("Invoking the next Interceptor in the chain "
134: + getNextInterceptor().getClass().getName());
135: return getNextInterceptor().invoke(pt);
136: } else {
137: if (log.isDebugEnabled())
138: log.debug("This is the end of the Interceptor chain");
139: return output;
140: }
141: }
142: }
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