--- /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.content;\r
+\r
+import java.util.Arrays;\r
+import java.util.Collection;\r
+import java.util.Collections;\r
+\r
+import org.simantics.browsing.ui.GraphExplorer;\r
+import org.simantics.browsing.ui.NodeContext;\r
+import org.simantics.browsing.ui.PrimitiveQueryUpdater;\r
+import org.simantics.browsing.ui.Tester;\r
+\r
+/**\r
+ * TODO: FIX THIS JAVADOC IT IS OUT-OF-DATE\r
+ * \r
+ * A Viewpoint is used for describing the child node generation of a single UI\r
+ * (e.g. tree) node. Viewpoints are created on a per UI node basis, including\r
+ * the invisible root input of provided to\r
+ * {@link GraphExplorer#setRoot(Object)}. Viewpoints are created by\r
+ * {@link ViewpointFactory}s.\r
+ * \r
+ * <p>\r
+ * A Viewpoint is responsible for informing of any changes happening in the set\r
+ * of children provided by it. Updates are performed using the\r
+ * {@link PrimitiveQueryUpdater} received by the {@link ViewpointFactory} that\r
+ * created the Viewpoint. To signal that the set of children has (possibly)\r
+ * changed, invoke\r
+ * {@link PrimitiveQueryUpdater#scheduleReplace(NodeContext, org.simantics.browsing.ui.NodeContext.PrimitiveQueryKey, Object)}\r
+ * and eventually the query system will re-request the viewpoint for the new\r
+ * children.\r
+ * </p>\r
+ * \r
+ * @author Antti Villberg\r
+ * \r
+ * @see ViewpointStub\r
+ */\r
+public interface ViewpointContribution {\r
+\r
+ /**\r
+ * Implementers can use this collection as a return value of\r
+ * {@link #getContribution()} when the contribution implementation is\r
+ * asynchronous and the real result will be updated later.\r
+ * \r
+ * <p>\r
+ * It is purposefully a different instance than {@link #NO_CONTRIBUTION}.\r
+ */\r
+ Collection<NodeContext> PENDING_CONTRIBUTION = Arrays.asList();\r
+\r
+ /**\r
+ * Return this from {@link #getContribution()} to indicate that no viewpoint\r
+ * contributions are available.\r
+ */\r
+ Collection<NodeContext> NO_CONTRIBUTION = Collections.emptyList();\r
+\r
+ /**\r
+ * @return a collection of contributions, must not be <code>null</code>\r
+ */\r
+ Collection<NodeContext> getContribution();\r
+\r
+ /**\r
+ * @return <code>null</code> if there is no tester\r
+ */\r
+ Tester getNodeContextTester();\r
+\r
+ Class<?> getInputClass();\r
+ \r
+}\r