bundles/org.simantics.browsing.ui.graph.impl/src/org/simantics/browsing/ui/graph/impl/contribution/FinalViewpointContributionImpl.java

   1 /*******************************************************************************
   2  * Copyright (c) 2007, 2010 Association for Decentralized Information Management
   3  * in Industry THTH ry.
   4  * All rights reserved. This program and the accompanying materials
   5  * are made available under the terms of the Eclipse Public License v1.0
   6  * which accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *     VTT Technical Research Centre of Finland - initial API and implementation
  11  *******************************************************************************/
  12 package org.simantics.browsing.ui.graph.impl.contribution;
  13
  14 import java.util.Collection;
  15
  16 import org.simantics.browsing.ui.BuiltinKeys;
  17 import org.simantics.browsing.ui.DataSource;
  18 import org.simantics.browsing.ui.NodeContext;
  19 import org.simantics.browsing.ui.PrimitiveQueryUpdater;
  20 import org.simantics.browsing.ui.Tester;
  21 import org.simantics.browsing.ui.content.ViewpointContribution;
  22 import org.simantics.browsing.ui.graph.impl.request.ResourceQuery;
  23 import org.simantics.db.AsyncReadGraph;
  24 import org.simantics.db.ReadGraph;
  25 import org.simantics.db.exception.DatabaseException;
  26 import org.simantics.db.procedure.Listener;
  27 import org.simantics.db.procedure.Procedure;
  28 import org.simantics.utils.ui.ErrorLogger;
  29
  30 /**
  31  * Implement {@link #children(AsyncReadGraph)} and {@link #hasChildren(AsyncReadGraph)}.
  32  *
  33  * @author Tuukka Lehtonen
  34  */
  35 abstract public class FinalViewpointContributionImpl extends ContributionStub implements GraphContribution {
  36
  37     final private ResourceQuery<Collection<NodeContext>> childQuery;
  38     final private Procedure<Collection<NodeContext>>     childProcedure;
  39
  40     final protected PrimitiveQueryUpdater       updater;
  41     final private NodeContext                context;
  42     final private BuiltinKeys.ViewpointContributionKey    key;
  43
  44     /**
  45      * This identity is used to give the back-end graph requests a
  46      * <em>properly unique</em> identity that so that the graph back-end caching
  47      * and graph explorer node context caching work together properly.
  48      *
  49      * Consider having two graph explorer instances that have the same
  50      * configuration (same evaluators) and are showing the same resource from
  51      * the graph database. In this case the requests are actually meant to have
  52      * an identical identity and performing the graph request will simply bind a
  53      * new listener for the one and same request.
  54      *
  55      * @return an additional identity for graph back-end requests to make them
  56      *         properly unique
  57      */
  58     public Object getIdentity() {
  59         return key;
  60     }
  61
  62     public FinalViewpointContributionImpl(final PrimitiveQueryUpdater updater, NodeContext context, BuiltinKeys.ViewpointContributionKey key) {
  63
  64         assert updater != null;
  65         assert context != null;
  66         assert key != null;
  67
  68         this.updater = updater;
  69         this.context = context;
  70         this.key = key;
  71
  72         this.childQuery = new ResourceQuery<Collection<NodeContext>>(getIdentity(), context) {
  73
  74             @Override
  75             public Collection<NodeContext> perform(ReadGraph graph) throws DatabaseException {
  76                 try {
  77                     // Make sure that null is not returned.
  78                     Collection<NodeContext> result = children(graph, context);
  79                     if (result == null)
  80                         throw new NullPointerException("LazyContributionImpl.children is not allowed to return null, but " + FinalViewpointContributionImpl.this.getClass() + " just did it");
  81                     return result;
  82                 } catch (DatabaseException e) {
  83                     throw e;
  84                 } catch (Throwable t) {
  85                     ErrorLogger.defaultLogError("LazyContributionImpl.childQuery produced unexpected exception.", t);
  86                     return ViewpointContribution.NO_CONTRIBUTION;
  87                 }
  88             }
  89
  90             @Override
  91             public String toString() {
  92                 return "LazyContributionImpl[" + System.identityHashCode(FinalViewpointContributionImpl.this) + "].childQuery";
  93             }
  94
  95         };
  96
  97         childProcedure = createProcedure();
  98
  99     }
 100
 101     protected Procedure<Collection<NodeContext>> createProcedure() {
 102
 103         return new Procedure<Collection<NodeContext>>() {
 104
 105             @Override
 106             public void execute(Collection<NodeContext> result) {
 107                 replaceChildrenResult(result);
 108             }
 109
 110             public void exception(Throwable t) {
 111                 ErrorLogger.defaultLogError("LazyContributionImpl.childQuery failed, see exception for details.", t);
 112             }
 113
 114             @Override
 115             public String toString() {
 116                 return "LazyContributionImpl[" + System.identityHashCode(FinalViewpointContributionImpl.this) + "].childProcedure";
 117             }
 118
 119         };
 120
 121     }
 122
 123     public NodeContext getContext() {
 124         return context;
 125     }
 126
 127     @Override
 128     public Collection<NodeContext> getContribution() {
 129
 130         //System.out.println("LazyViewpoint2@" + System.identityHashCode(this) + " getChildren() = " + children.length);
 131
 132         if (children == org.simantics.browsing.ui.content.ViewpointContribution.PENDING_CONTRIBUTION) {
 133             DataSource<ReadGraph> source = updater.getDataSource(ReadGraph.class);
 134             if (source != null) {
 135                 source.schedule(graph -> {
 136                     if(childProcedure instanceof Listener<?>)
 137                         graph.asyncRequest(childQuery, (Listener<Collection<NodeContext>>)childProcedure);
 138                     else
 139                         graph.asyncRequest(childQuery, childProcedure);
 140                 });
 141             }
 142         }
 143
 144         //System.out.println("LazyViewpoint.getChildren returns " + children);
 145
 146         return children;
 147
 148     }
 149
 150     protected void replaceChildrenResult(Collection<NodeContext> result) {
 151         setChildren(updater, result);
 152         updater.scheduleReplace(context, key, this);
 153     }
 154
 155     /**
 156      * @param <T>
 157      * @param clazz
 158      * @return input of the specified class
 159      * @throws ClassCastException if the input class does not match the
 160      *         specified class
 161      * @throws NullPointerException if the input is null
 162      */
 163     @SuppressWarnings("unchecked")
 164     protected <T> T getInput(Class<T> clazz) throws ClassCastException {
 165         Object o = context.getConstant(BuiltinKeys.INPUT);
 166         if (o == null)
 167             throw new NullPointerException("null input");
 168 //        return clazz.cast(o);
 169         return (T) o;
 170     }
 171
 172     /**
 173      * @param <T>
 174      * @param clazz
 175      * @return <code>null</code> if input is <code>null</code> or if the class does not match
 176      */
 177     @SuppressWarnings("unchecked")
 178     protected <T> T tryGetInput(Class<T> clazz) {
 179         Object o = context.getConstant(BuiltinKeys.INPUT);
 180         if (o != null && clazz.isInstance(o))
 181 //            return clazz.cast(o);
 182             return (T) o;
 183         return null;
 184     }
 185
 186     @Override
 187     public Tester getNodeContextTester() {
 188         return null;
 189     }
 190
 191 }