001 /*
002 * Cumulus4j - Securing your data in the cloud - http://cumulus4j.org
003 * Copyright (C) 2011 NightLabs Consulting GmbH
004 *
005 * This program is free software: you can redistribute it and/or modify
006 * it under the terms of the GNU Affero General Public License as
007 * published by the Free Software Foundation, either version 3 of the
008 * License, or (at your option) any later version.
009 *
010 * This program is distributed in the hope that it will be useful,
011 * but WITHOUT ANY WARRANTY; without even the implied warranty of
012 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
013 * GNU Affero General Public License for more details.
014 *
015 * You should have received a copy of the GNU Affero General Public License
016 * along with this program. If not, see <http://www.gnu.org/licenses/>.
017 */
018 package org.cumulus4j.store;
019
020 import java.util.Properties;
021
022 import javax.jdo.PersistenceManager;
023
024 import org.cumulus4j.store.model.Sequence;
025 import org.datanucleus.store.connection.ManagedConnection;
026 import org.datanucleus.store.valuegenerator.AbstractDatastoreGenerator;
027 import org.datanucleus.store.valuegenerator.ValueGenerationBlock;
028 import org.datanucleus.store.valuegenerator.ValueGenerator;
029
030 /**
031 * {@link ValueGenerator} implementation generating values by incrementing a counter.
032 * @author Marco หงุ่ยตระกูล-Schulze - marco at nightlabs dot de
033 */
034 public class Cumulus4jIncrementGenerator extends AbstractDatastoreGenerator
035 {
036 private String sequenceName;
037
038 /**
039 * Create an instance. This is called by DataNucleus.
040 * @param name symbolic name for the generator.
041 * @param props Properties controlling the behaviour of the generator.
042 */
043 public Cumulus4jIncrementGenerator(String name, Properties props) {
044 super(name, props);
045 allocationSize = 5;
046
047 // TODO Check these names and what we want to use for Cumulus4j (classname or fieldname)
048 if (properties.getProperty("sequence-name") != null) {
049 // Specified sequence-name so use that
050 sequenceName = properties.getProperty("sequence-name");
051 }
052 else if (properties.getProperty("field-name") != null) {
053 // Use field name as the sequence name so we have one sequence per field on the class
054 sequenceName = properties.getProperty("field-name");
055 }
056 else {
057 // Use actual class name as the sequence name so we have one sequence per class
058 sequenceName = properties.getProperty("class-name");
059 }
060 }
061
062 @Override
063 protected ValueGenerationBlock reserveBlock(long size) {
064 if (size > Integer.MAX_VALUE)
065 throw new IllegalStateException("Cannot reserve a block of more than " + Integer.MAX_VALUE + " values!");
066
067 Long[] values = new Long[(int)size];
068 ManagedConnection mconn = connectionProvider.retrieveConnection();
069 try {
070 PersistenceManagerConnection pmConn = (PersistenceManagerConnection)mconn.getConnection();
071 PersistenceManager pm = pmConn.getDataPM();
072 pm.currentTransaction().setSerializeRead(true);
073 try {
074 Sequence sequence = Sequence.createSequence(pm, sequenceName);
075 long nextValue = sequence.getNextValue();
076 for (int idx = 0; idx < values.length; ++idx) {
077 values[idx] = nextValue++;
078 }
079 sequence.setNextValue(nextValue);
080 } finally {
081 pm.currentTransaction().setSerializeRead(false);
082 }
083 } finally {
084 connectionProvider.releaseConnection();
085 }
086 return new ValueGenerationBlock(values);
087 }
088 }