X-Git-Url: https://gerrit.simantics.org/r/gitweb?p=simantics%2Fplatform.git;a=blobdiff_plain;f=bundles%2Forg.simantics.browsing.ui.graph.impl%2Fsrc%2Forg%2Fsimantics%2Fbrowsing%2Fui%2Fgraph%2Fimpl%2FLazyViewpoint.java;fp=bundles%2Forg.simantics.browsing.ui.graph.impl%2Fsrc%2Forg%2Fsimantics%2Fbrowsing%2Fui%2Fgraph%2Fimpl%2FLazyViewpoint.java;h=44bd6a9810f2242ec28a54db85bb67e0c50ba329;hp=0000000000000000000000000000000000000000;hb=969bd23cab98a79ca9101af33334000879fb60c5;hpb=866dba5cd5a3929bbeae85991796acb212338a08

diff --git a/bundles/org.simantics.browsing.ui.graph.impl/src/org/simantics/browsing/ui/graph/impl/LazyViewpoint.java b/bundles/org.simantics.browsing.ui.graph.impl/src/org/simantics/browsing/ui/graph/impl/LazyViewpoint.java
new file mode 100644
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+/*******************************************************************************
+ * Copyright (c) 2007, 2010 Association for Decentralized Information Management
+ * in Industry THTH ry.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     VTT Technical Research Centre of Finland - initial API and implementation
+ *******************************************************************************/
+package org.simantics.browsing.ui.graph.impl;
+
+import java.util.function.Consumer;
+
+import org.simantics.browsing.ui.BuiltinKeys;
+import org.simantics.browsing.ui.DataSource;
+import org.simantics.browsing.ui.NodeContext;
+import org.simantics.browsing.ui.PrimitiveQueryUpdater;
+import org.simantics.browsing.ui.common.viewpoints.ViewpointStub;
+import org.simantics.browsing.ui.content.Viewpoint;
+import org.simantics.browsing.ui.graph.impl.request.ResourceQuery;
+import org.simantics.db.ReadGraph;
+import org.simantics.db.exception.DatabaseException;
+import org.simantics.db.procedure.Listener;
+import org.simantics.utils.datastructures.Pair;
+
+/**
+ * Implement {@link #children(ReadGraph)} and {@link #hasChildren(ReadGraph)}.
+ * 
+ * @author Tuukka Lehtonen
+ */
+public abstract class LazyViewpoint extends ViewpointStub {
+
+    /**
+     * Needed for separating childQuery and hasChildQuery from each other in the
+     * equals sense.
+     */
+    private static final Object                 CHILDREN     = new Object();
+
+    final private ResourceQuery<NodeContext[]> childQuery;
+
+    final protected PrimitiveQueryUpdater       updater;
+    final protected NodeContext                context;
+    final protected BuiltinKeys.ViewpointKey    key;
+
+    /**
+     * @param graph
+     * @return
+     */
+    public abstract NodeContext[] children(ReadGraph graph) throws DatabaseException;
+
+    /**
+     * @param graph
+     * @return
+     */
+    public abstract Boolean hasChildren(ReadGraph graph) throws DatabaseException;
+
+    /**
+     * This identity is used to give the back-end graph requests a
+     * <em>properly unique</em> identity that so that the graph back-end caching
+     * and graph explorer node context caching work together properly.
+     * 
+     * Consider having two graph explorer instances that have the same
+     * configuration (same evaluators) and are showing the same resource from
+     * the graph database. In this case the requests are actually meant to have
+     * an identical identity and performing the graph request will simply bind a
+     * new listener for the one and same request.
+     * 
+     * @return an additional identity for graph back-end requests to make them
+     *         properly unique
+     */
+    public Object getIdentity() {
+        return key;
+    }
+
+    public LazyViewpoint(final PrimitiveQueryUpdater updater, NodeContext context, BuiltinKeys.ViewpointKey key) {
+
+        assert updater != null;
+        assert context != null;
+        assert key != null;
+
+        this.updater = updater;
+        this.context = context;
+        this.key = key;
+
+        this.childQuery = new ResourceQuery<NodeContext[]>(Pair.make(getIdentity(), CHILDREN), context) {
+
+            @Override
+            public NodeContext[] perform(ReadGraph graph) throws DatabaseException {
+                return children(graph);
+            }
+
+            @Override
+            public String toString() {
+                return LazyViewpoint.this.toString() + "[CHILDREN]";
+            }
+
+        };
+
+    }
+
+    private Listener<NodeContext[]> createListener() {
+    	
+    	return new Listener<NodeContext[]>() {
+
+    		boolean executed = false;
+    		boolean disposed = false;
+    		
+            @Override
+            public void execute(NodeContext[] result) {
+                replaceChildrenResult(result);
+                executed = true;
+            }
+
+            @Override
+            public boolean isDisposed() {
+             	if(disposed) return true;
+
+            	if((updater.isDisposed() || !updater.isShown(context)) && executed) {
+            		children = Viewpoint.PENDING_CHILDREN;
+            		disposed = true;
+            		return true;
+            	} else {
+            		return false;
+            	}
+            	
+            }
+
+            public void exception(Throwable t) {
+                System.out.print("LazyViewpoint.childQuery failed: ");
+                t.printStackTrace();
+            }
+
+            @Override
+            public String toString() {
+                return "LazyViewpoint[" + System.identityHashCode(LazyViewpoint.this) + "].childProcedure";
+            }
+
+        };
+    	
+    }
+    
+    public NodeContext getContext() {
+        return context;
+    }
+
+    @Override
+    public NodeContext[] getChildren() {
+
+        if (children == Viewpoint.PENDING_CHILDREN) {
+            DataSource<ReadGraph> source = updater.getDataSource(ReadGraph.class);
+            final Listener<NodeContext[]> childProcedure = createListener();
+            source.schedule(new Consumer<ReadGraph>() {
+                @Override
+                public void accept(ReadGraph source) {
+                    source.asyncRequest(childQuery, childProcedure);
+                }
+            });
+        }
+
+        return children;
+
+    }
+
+    @Override
+    public Boolean getHasChildren() {
+    	return getChildren().length > 0;
+    }
+
+    protected void replaceChildrenResult(NodeContext[] result) {
+        setChildren(updater, result);
+        updater.scheduleReplace(context, key, this);
+    }
+
+    /**
+     * @param <T>
+     * @param clazz
+     * @return input of the specified class
+     * @throws ClassCastException if the input class does not match the
+     *         specified class
+     * @throws NullPointerException if the input is null
+     */
+    @SuppressWarnings("unchecked")
+    protected <T> T getInput(Class<T> clazz) throws ClassCastException {
+        Object o = context.getConstant(BuiltinKeys.INPUT);
+        if (o == null)
+            throw new NullPointerException("null input");
+        return (T) o;
+    }
+
+    /**
+     * @param <T>
+     * @param clazz
+     * @return <code>null</code> if input is <code>null</code> or if the class does not match
+     */
+    @SuppressWarnings("unchecked")
+    protected <T> T tryGetInput(Class<T> clazz) {
+        Object o = context.getConstant(BuiltinKeys.INPUT);
+        if (o != null && clazz.isInstance(o))
+            return (T) o;
+        return null;
+    }
+
+}