001    /*
002    // $Id: //open/mondrian/src/main/mondrian/spi/impl/DataSourceChangeListenerImpl.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 mondrian.spi.DataSourceChangeListener;
013    import mondrian.olap.MondrianDef;
014    import mondrian.rolap.RolapHierarchy;
015    import mondrian.rolap.agg.Aggregation;
016    
017    
018    /**
019     * Default implementation of a data source change listener
020     * that always returns that the datasource is unchanged.
021     *
022     * A change listener can be specified in the connection string.  It is used
023     * to ask what is changed in the datasource (e.g. database).
024     *
025     * Everytime mondrian has to decide whether it will use data from cache, it
026     * will call the change listener.  When the change listener tells mondrian
027     * the datasource has changed for a dimension, cube, ... then mondrian will
028     * flush the cache and read from database again.
029     *
030     * It is specified in the connection string, like this:
031     *
032     * <blockquote><code>
033     * Jdbc=jdbc:odbc:MondrianFoodMart; JdbcUser=ziggy; JdbcPassword=stardust; DataSourceChangeListener=com.acme.MyChangeListener;
034     * </code></blockquote>
035     *
036     * This class should be called in mondrian before any data is read, so
037     * even before cache is build.  This way, the plugin is able to register
038     * the first timestamp mondrian tries to read the datasource.
039     *
040     * @author Bart Pappyn
041     * @version $Id: //open/mondrian/src/main/mondrian/spi/impl/DataSourceChangeListenerImpl.java#6 $
042     * @since Dec 12, 2006
043     */
044    
045    public class DataSourceChangeListenerImpl implements DataSourceChangeListener {
046    
047        /** Creates a new instance of DataSourceChangeListenerImpl */
048        public DataSourceChangeListenerImpl() {
049        }
050    
051    
052        public synchronized boolean isHierarchyChanged(RolapHierarchy hierarchy) {
053            return false;
054        }
055    
056        public synchronized boolean isAggregationChanged(Aggregation aggregation) {
057            return false;
058        }
059    
060        public String getTableName(RolapHierarchy hierarchy) {
061            MondrianDef.RelationOrJoin relation = hierarchy.getRelation();
062            if (relation instanceof MondrianDef.Table) {
063                MondrianDef.Table tableRelation = (MondrianDef.Table) relation;
064                return tableRelation.name;
065            } else {
066                return null;
067            }
068        }
069    }
070    
071    // End DataSourceChangeListenerImpl.java