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%2FLazyGraphQueryProcessor.java;fp=bundles%2Forg.simantics.browsing.ui.graph.impl%2Fsrc%2Forg%2Fsimantics%2Fbrowsing%2Fui%2Fgraph%2Fimpl%2FLazyGraphQueryProcessor.java;h=00277d4fd3e36956e2854764744335f5f0112db2;hp=0000000000000000000000000000000000000000;hb=969bd23cab98a79ca9101af33334000879fb60c5;hpb=866dba5cd5a3929bbeae85991796acb212338a08

diff --git a/bundles/org.simantics.browsing.ui.graph.impl/src/org/simantics/browsing/ui/graph/impl/LazyGraphQueryProcessor.java b/bundles/org.simantics.browsing.ui.graph.impl/src/org/simantics/browsing/ui/graph/impl/LazyGraphQueryProcessor.java
new file mode 100644
index 000000000..00277d4fd
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+++ b/bundles/org.simantics.browsing.ui.graph.impl/src/org/simantics/browsing/ui/graph/impl/LazyGraphQueryProcessor.java
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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 org.simantics.browsing.ui.NodeContext;
+import org.simantics.browsing.ui.PrimitiveQueryUpdater;
+import org.simantics.browsing.ui.NodeContext.PrimitiveQueryKey;
+import org.simantics.browsing.ui.common.processors.AbstractPrimitiveQueryProcessor;
+import org.simantics.db.ReadGraph;
+import org.simantics.db.exception.DatabaseException;
+import org.simantics.utils.Container;
+
+public abstract class LazyGraphQueryProcessor<Result> extends AbstractPrimitiveQueryProcessor<Container<Result>> {
+
+    /**
+     * Returns the value to be returned as the initial query result, before the
+     * real result has been calculated.
+     * 
+     * @return the initial result value stored in the returned {@link Container}
+     */
+    protected abstract Result initial();
+
+    /**
+     * 
+     * @param graph
+     * @param context
+     * @return
+     */
+    protected abstract Result compute(ReadGraph graph, NodeContext context, PrimitiveQueryKey<Container<Result>> key) throws DatabaseException;
+
+    final Result init = initial();
+
+    @Override
+    public Container<Result> query(PrimitiveQueryUpdater updater, NodeContext context,
+            final PrimitiveQueryKey<Container<Result>> key) {
+        assert(updater != null);
+        assert(context != null);
+        assert(key != null);
+
+        return new LazyResourceQueryContainer<Result>(updater, context, init) {
+            @Override
+            protected PrimitiveQueryKey<Container<Result>> getKey() {
+                return key;
+            }
+
+            @Override
+            protected Result compute(ReadGraph graph) throws DatabaseException {
+                return LazyGraphQueryProcessor.this.compute(graph, context, key);
+            }
+        };
+    }
+
+    @Override
+    public String toString() {
+        return "abstract LazyGraphQueryProcessor2";
+    }
+
+}