sascha@403: package de.intevation.artifactdatabase.state;
sascha@403: 
sascha@403: import de.intevation.artifacts.Artifact;
sascha@403: 
sascha@405: import java.util.ArrayList;
sascha@403: import java.util.HashMap;
sascha@405: import java.util.List;
sascha@403: import java.util.Map;
sascha@403: 
felix@438: import org.apache.log4j.Logger;
felix@436: 
felix@438: 
felix@438: /**
felix@438:  * System used in practice used by AttributeWriter in flys-artifacts to decide
felix@438:  * whether a facet is initially active.
felix@438:  * Provides a singleton Registry into which FacetActivities can be registered
felix@438:  * under a key (in practice the artifacts name.  This Registry is queried for
felix@438:  * new Facets in order to find whether they are active or inactive.
felix@438:  */
sascha@403: public interface FacetActivity
sascha@403: {
felix@436:     /** Static 'activity' that lets all facets be active. */
sascha@403:     public static final FacetActivity ACTIVE = new FacetActivity() {
sascha@403:         @Override
sascha@405:         public Boolean isInitialActive(
sascha@403:             Artifact artifact,
sascha@403:             Facet    facet,
sascha@403:             String   output
sascha@403:         ) {
sascha@405:             return Boolean.TRUE;
sascha@403:         }
sascha@403:     };
sascha@403: 
felix@436:     /** Static 'activity' that lets all facets be inactive. */
sascha@403:     public static final FacetActivity INACTIVE = new FacetActivity() {
sascha@403:         @Override
sascha@405:         public Boolean isInitialActive(
sascha@403:             Artifact artifact,
sascha@403:             Facet    facet,
sascha@403:             String   output
sascha@403:         ) {
sascha@405:             return Boolean.FALSE;
sascha@403:         }
sascha@403:     };
sascha@403: 
sascha@405:     Boolean isInitialActive(Artifact artifact, Facet facet, String output);
sascha@403: 
felix@436:     /** Singleton registry, that maps artifact names to the activities, which
felix@436:      * decide whether or not a facet should be (initially) active. */
sascha@403:     public static final class Registry {
sascha@403: 
felix@438:         /** The logger for this class. */
felix@438:         private static Logger logger = Logger.getLogger(Registry.class);
felix@438: 
felix@436:         /** Singleton instance. */
sascha@403:         private static final Registry INSTANCE = new Registry();
sascha@403: 
felix@438:         /** Map of keys (artifact names) to the activities. */
sascha@405:         private Map<String, List<FacetActivity>> activities;
sascha@403: 
felix@436:         /** Private singleton constructor for the Facet-Activity-Registry. */
sascha@403:         private Registry() {
sascha@405:             activities = new HashMap<String, List<FacetActivity>>();
sascha@403:         }
sascha@403: 
felix@436:         /** Access Singleton instance. */
sascha@404:         public static Registry getInstance() {
sascha@403:             return INSTANCE;
sascha@403:         }
sascha@403: 
felix@436:         /** Queries whether a given facet should be active or not. */
sascha@405:         public synchronized boolean isInitialActive(
sascha@405:             String   key,
sascha@405:             Artifact artifact,
sascha@405:             Facet    facet,
sascha@405:             String   output
sascha@405:         ) {
sascha@405:             List<FacetActivity> activityList = activities.get(key);
sascha@405:             if (activityList == null) {
felix@443:                 logger.debug("FacetActivity.Registry: No activity " +
felix@438:                              "registered for " + key);
sascha@405:                 return true;
sascha@405:             }
felix@438:             if (activityList.size() != 1) {
felix@443:                 logger.warn("FacetActivity.Registry: More than one " +
felix@438:                             "FacetActivity registered for " + key);
felix@438:             }
sascha@405:             for (FacetActivity activity: activityList) {
sascha@405:                 Boolean isActive =
sascha@405:                     activity.isInitialActive(artifact, facet, output);
felix@438:                 // Nice. Only, in practice they never return NULL.
sascha@405:                 if (isActive != null) {
sascha@405:                     return isActive;
sascha@405:                 }
sascha@405:             }
sascha@405:             return true;
sascha@403:         }
sascha@403: 
felix@438: 
felix@438:         /** Add a FacetActivity under given key (usually artifacts name). */
sascha@403:         public synchronized void register(String key, FacetActivity activity) {
sascha@405:             List<FacetActivity> activityList = activities.get(key);
sascha@405:             if (activityList == null) {
sascha@405:                 activityList = new ArrayList<FacetActivity>(3);
sascha@405:                 activities.put(key, activityList);
sascha@405:             }
sascha@405:             activityList.add(activity);
sascha@403:         }
sascha@403:     }
sascha@403: }
sascha@403: // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf-8 :