001 /*
002 // $Id: //open/mondrian/src/main/mondrian/spi/impl/DataSourceChangeListenerImpl4.java#6 $
003 // This software is subject to the terms of the Common Public License
004 // Agreement, available at the following URL:
005 // http://www.opensource.org/licenses/cpl.html.
006 // Copyright (C) 2005-2008 Julian Hyde
007 // All Rights Reserved.
008 // You must accept the terms of that agreement to use this software.
009 */
010 package mondrian.spi.impl;
011
012 import java.util.Random;
013
014 import mondrian.spi.DataSourceChangeListener;
015 import mondrian.olap.MondrianDef;
016 import mondrian.rolap.RolapHierarchy;
017 import mondrian.rolap.agg.Aggregation;
018
019
020 /**
021 * Default implementation of a data source change listener
022 * that always returns that the datasource is changed.
023 *
024 * A change listener can be specified in the connection string. It is used
025 * to ask what is changed in the datasource (e.g. database).
026 *
027 * Everytime mondrian has to decide whether it will use data from cache, it
028 * will call the change listener. When the change listener tells mondrian
029 * the datasource has changed for a dimension, cube, ... then mondrian will
030 * flush the cache and read from database again.
031 *
032 * It is specified in the connection string, like this:
033 *
034 * <blockquote><code>
035 * Jdbc=jdbc:odbc:MondrianFoodMart; JdbcUser=ziggy; JdbcPassword=stardust; DataSourceChangeListener=com.acme.MyChangeListener;
036 * </code></blockquote>
037 *
038 * This class should be called in mondrian before any data is read, so
039 * even before cache is build. This way, the plugin is able to register
040 * the first timestamp mondrian tries to read the datasource.
041 *
042 * @author Bart Pappyn
043 * @version $Id: //open/mondrian/src/main/mondrian/spi/impl/DataSourceChangeListenerImpl4.java#6 $
044 * @since Dec 12, 2006
045 */
046
047 public class DataSourceChangeListenerImpl4 implements DataSourceChangeListener {
048 private int flushInverseFrequencyHierarchy;
049 private int flushInverseFrequencyAggregation;
050 final Random random = new Random(123456);
051
052 /** Creates a new instance of DataSourceChangeListenerImpl2 */
053 public DataSourceChangeListenerImpl4() {
054 this(0,0);
055 }
056 public DataSourceChangeListenerImpl4(int flushInverseFrequencyHierarchy,
057 int flushInverseFrequencyAggregation) {
058 this.flushInverseFrequencyHierarchy = flushInverseFrequencyHierarchy;
059 this.flushInverseFrequencyAggregation = flushInverseFrequencyAggregation;
060 }
061
062 public synchronized boolean isHierarchyChanged(RolapHierarchy hierarchy) {
063 if (flushInverseFrequencyHierarchy != 0) {
064 if (random.nextInt(flushInverseFrequencyHierarchy) == 0) {
065 return true;
066 } else {
067 return false;
068 }
069 } else {
070 return true;
071 }
072 }
073
074 public synchronized boolean isAggregationChanged(Aggregation aggregation) {
075 if (flushInverseFrequencyAggregation != 0) {
076 if (random.nextInt(flushInverseFrequencyAggregation) == 0) {
077 return true;
078 } else {
079 return false;
080 }
081 } else {
082 return true;
083 }
084 }
085
086 public String getTableName(RolapHierarchy hierarchy) {
087 MondrianDef.RelationOrJoin relation = hierarchy.getRelation();
088 if (relation instanceof MondrianDef.Table) {
089 MondrianDef.Table tableRelation = (MondrianDef.Table)relation;
090 return tableRelation.name;
091 } else {
092 return null;
093 }
094 }
095 }
096
097 // End DataSourceChangeListenerImpl4.java