franta-hg@1: /*
franta-hg@1:  * Created on 13.04.2003
franta-hg@1:  *
franta-hg@1:  * To change the template for this generated file go to
franta-hg@1:  * Window>Preferences>Java>Code Generation>Code and Comments
franta-hg@1:  */
franta-hg@1: package de.laures.cewolf.taglib;
franta-hg@1: 
franta-hg@1: import java.io.Serializable;
franta-hg@1: import java.util.Date;
franta-hg@1: import java.util.Map;
franta-hg@1: 
franta-hg@1: import org.apache.commons.logging.Log;
franta-hg@1: import org.apache.commons.logging.LogFactory;
franta-hg@1: import org.jfree.data.general.Dataset;
franta-hg@1: 
franta-hg@1: import de.laures.cewolf.DatasetProduceException;
franta-hg@1: import de.laures.cewolf.DatasetProducer;
franta-hg@1: import de.laures.cewolf.taglib.util.DatasetProductionTimeStore;
franta-hg@1: import de.laures.cewolf.taglib.util.KeyGenerator;
franta-hg@1: import de.laures.cewolf.util.Assert;
franta-hg@1: 
franta-hg@1: /**
franta-hg@1:  * @author guido
franta-hg@1:  *
franta-hg@1:  * To change the template for this generated type comment go to
franta-hg@1:  * Window>Preferences>Java>Code Generation>Code and Comments
franta-hg@1:  */
franta-hg@1: public class DataContainer implements DataAware, Serializable {
franta-hg@1: 
franta-hg@1:     private static transient final Log log = LogFactory.getLog(ChartImageDefinition.class);
franta-hg@1: 
franta-hg@1:     private transient Dataset data;
franta-hg@1:     private transient DatasetProducer producer;
franta-hg@1: 
franta-hg@1:     private Map datasetProductionParams;
franta-hg@1:     private long datasetProduceTime;
franta-hg@1:     private boolean useCache = true;
franta-hg@1: 
franta-hg@1:     public void setDataProductionConfig(DatasetProducer dsp, Map params, boolean useCache) {
franta-hg@1:         log.debug("setDataProductionConfig");
franta-hg@1:         producer = dsp;
franta-hg@1:         datasetProductionParams = params;
franta-hg@1:         this.useCache = useCache;
franta-hg@1:         checkDataProductionNeed();
franta-hg@1:     }
franta-hg@1: 
franta-hg@1:     public Object getDataset() throws DatasetProduceException {
franta-hg@1:         Assert.check(producer != null, "you need to specifiy a producer for the data of the chart.");
franta-hg@1:         log.debug("getting data..");
franta-hg@1:         if (data == null) {
franta-hg@1:             log.debug("producing new dataset for " + producer.getProducerId());
franta-hg@1:             data = (Dataset) producer.produceDataset(datasetProductionParams);
franta-hg@1:             DatasetProductionTimeStore dataCache = DatasetProductionTimeStore.getInstance();
franta-hg@1:             dataCache.addEntry(producer.getProducerId(), datasetProductionParams, new Date(datasetProduceTime));
franta-hg@1:         }
franta-hg@1:         Assert.check(data != null, "your producer of type " + producer.getClass().getName() + " produced a null dataset.");
franta-hg@1:         return data;
franta-hg@1:     }
franta-hg@1: 
franta-hg@1:     /**
franta-hg@1:      * This method checks if there has been a dataset production 
franta-hg@1:      * for the same DatasetProvider and parameters. If so the DatasetProducer
franta-hg@1:      * is consulted to check the expiry of this data.
franta-hg@1:      * If the data has expired the retrieval of a cached image of this
franta-hg@1:      * ChartDefinition is avoided by setting the datasetProduceTime to the
franta-hg@1:      * actual time. After this the hash code of this object can not be
franta-hg@1:      * present in the image cache and so a new image with new data will
franta-hg@1:      * be rendered.
franta-hg@1:      * If the data did not expire the last dataset production time is stored
franta-hg@1:      * as a memeber to reach the same hash code for this object as the one
franta-hg@1:      * before if possible.
franta-hg@1:      * This method is called during serialization to ensure the same serialized
franta-hg@1:      * representation of this and a eventually formally stored object.
franta-hg@1:      */
franta-hg@1:     private void checkDataProductionNeed() {
franta-hg@1:         log.debug("checking data actuality..." + producer + ", " + datasetProductionParams);
franta-hg@1:         final String prodId = producer.getProducerId();
franta-hg@1:         log.debug(prodId + ", " + KeyGenerator.generateKey((Serializable)datasetProductionParams));
franta-hg@1:         log.debug("useCache = " + useCache);
franta-hg@1:         DatasetProductionTimeStore dataCache = DatasetProductionTimeStore.getInstance();
franta-hg@1:         if (useCache && dataCache.containsEntry(prodId, datasetProductionParams)) {
franta-hg@1:             Date produceTime = dataCache.getProductionTime(prodId, datasetProductionParams);
franta-hg@1:             log.debug("cached data available.");
franta-hg@1:             // cached data available
franta-hg@1:             if (!producer.hasExpired(datasetProductionParams, produceTime)) {
franta-hg@1:                 log.debug("cached data is still valid.");
franta-hg@1:                 this.datasetProduceTime = produceTime.getTime();
franta-hg@1:                 return;
franta-hg@1:             }
franta-hg@1:             dataCache.removeEntry(prodId, datasetProductionParams);
franta-hg@1:         }
franta-hg@1:         datasetProduceTime = System.currentTimeMillis();
franta-hg@1:     }
franta-hg@1: 
franta-hg@1: }