Variable optimizations for documents (Simupedia)

[simantics/platform.git] / bundles / org.simantics.db.layer0 / src / org / simantics / db / layer0 / adapter / ContextualRelatedValue.java

diff --git a/bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/adapter/ContextualRelatedValue.java b/bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/adapter/ContextualRelatedValue.java
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+/*******************************************************************************
+ * Copyright (c) 2018 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:
+ *     Semantum Oy - initial API and implementation
+ *******************************************************************************/
+package org.simantics.db.layer0.adapter;
+
+import org.simantics.db.ConverterComputationalValue;
+import org.simantics.db.ReadGraph;
+import org.simantics.db.Resource;
+import org.simantics.db.exception.DatabaseException;
+import org.simantics.db.exception.RuntimeDatabaseException;
+import org.simantics.db.layer0.variable.Variable;
+import org.simantics.scl.runtime.SCLContext;
+import org.simantics.scl.runtime.function.Function1;
+import org.simantics.scl.runtime.function.FunctionImpl3;
+
+/**
+ * @author Antti Villberg
+ * @since 1.36.0
+ */
+public abstract class ContextualRelatedValue implements ConverterComputationalValue {
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public <T> T getValue(ReadGraph graph, Resource resource) throws DatabaseException {
+        return (T) new FunctionImpl3<ReadGraph, Resource, Object, Object>() {
+            @Override
+            public Object apply(ReadGraph graph, Resource converter, Object context) {
+                SCLContext sclContext = SCLContext.getCurrent();
+                Object oldGraph = sclContext.get("graph");
+                try {
+                    if (context instanceof Variable) {
+                        Variable variable = (Variable)context;
+                        try {
+                            Function1<Object,Object> fn = getFunction(graph, variable.getParent(graph).getRepresents(graph), variable.getRepresents(graph), variable.getPredicateResource(graph));
+                            sclContext.put("graph", graph);
+                            return fn.apply(variable);
+                        } catch (DatabaseException e) {
+                            throw new RuntimeDatabaseException(e);
+                        }
+                    } if (context instanceof Resource) {
+                        Resource resource = (Resource)context;
+                        try {
+                            // Here converter is the object and context is the subject
+                            Function1<Object,Object> fn = getFunction(graph, resource, converter, null);
+                            return fn.apply(resource);
+                        } catch (DatabaseException e) {
+                            throw new RuntimeDatabaseException(e);
+                        }
+                    } else {
+                        throw new IllegalStateException("Unknown context " + context);
+                    }
+                } finally {
+                    sclContext.put("graph", oldGraph);
+                }
+            }
+        };
+    }
+
+}