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