Variable optimizations for documents (Simupedia)

[simantics/platform.git] / bundles / org.simantics.document.server / src / org / simantics / document / server / DocumentProperties.java

diff --git a/bundles/org.simantics.document.server/src/org/simantics/document/server/DocumentProperties.java b/bundles/org.simantics.document.server/src/org/simantics/document/server/DocumentProperties.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.document.server;
+
+import java.util.Collection;
+
+import org.simantics.db.ReadGraph;
+import org.simantics.db.exception.DatabaseException;
+import org.simantics.db.layer0.variable.Variable;
+
+/**
+ * This interface abstracts the computation of document component properties.
+ * The key,value -pairs returned by this interface are used to build the
+ * org.simantics.document.server.JSONObject values used in the document
+ * scene graph.
+ *
+ * @author Antti Villberg
+ * @since 1.36.0
+ */
+public interface DocumentProperties {
+
+    /*
+     * Returns the set of attribute keys for the given document component.
+     * Does not return null.
+     */
+    Collection<String> getKeys(ReadGraph graph, Variable component) throws DatabaseException;
+    /*
+     * Returns a value for a key in the key set.
+     * Null values are allowed and normal DatabaseException
+     * are thrown when evaluating the value.
+     */
+    Object getValue(ReadGraph graph, Variable component, String key) throws DatabaseException;
+
+}