bundles/org.simantics.browsing.ui.graph.impl/src/org/simantics/browsing/ui/graph/impl/LazyViewpointFactory.java

   1 /*******************************************************************************\r
   2  * Copyright (c) 2007, 2010 Association for Decentralized Information Management\r
   3  * in Industry THTH ry.\r
   4  * All rights reserved. This program and the accompanying materials\r
   5  * are made available under the terms of the Eclipse Public License v1.0\r
   6  * which accompanies this distribution, and is available at\r
   7  * http://www.eclipse.org/legal/epl-v10.html\r
   8  *\r
   9  * Contributors:\r
  10  *     VTT Technical Research Centre of Finland - initial API and implementation\r
  11  *******************************************************************************/\r
  12 package org.simantics.browsing.ui.graph.impl;\r
  13 \r
  14 import java.util.Collection;\r
  15 \r
  16 import org.simantics.browsing.ui.NodeContext;\r
  17 import org.simantics.browsing.ui.PrimitiveQueryUpdater;\r
  18 import org.simantics.browsing.ui.BuiltinKeys.ViewpointKey;\r
  19 import org.simantics.browsing.ui.content.Viewpoint;\r
  20 import org.simantics.browsing.ui.content.ViewpointFactory;\r
  21 import org.simantics.db.ReadGraph;\r
  22 import org.simantics.db.exception.DatabaseException;\r
  23 \r
  24 /**\r
  25  * Extend and implement {@link #getChildren(ReadGraph, NodeContext)} to create a\r
  26  * viewpoint factory that reads from the graph database.\r
  27  * \r
  28  * @author Antti Villberg\r
  29  */\r
  30 public abstract class LazyViewpointFactory implements ViewpointFactory {\r
  31 \r
  32     @Override\r
  33     public Viewpoint create(PrimitiveQueryUpdater updater,\r
  34             NodeContext context, ViewpointKey key) {\r
  35         return new LazyViewpoint(updater, context, key) {\r
  36             @Override\r
  37             public NodeContext[] children(ReadGraph graph) throws DatabaseException {\r
  38                 return toContextsWithInput(LazyViewpointFactory.this.\r
  39                         getChildren(graph, context));\r
  40             }\r
  41 \r
  42             @Override\r
  43             public Boolean hasChildren(ReadGraph graph) throws DatabaseException {\r
  44                 return children(graph).length > 0;\r
  45             }\r
  46 \r
  47             @Override\r
  48             public String toString() {\r
  49                 return LazyViewpointFactory.this.toString();\r
  50             }\r
  51 \r
  52             @Override\r
  53             public Object getIdentity() {\r
  54                 return LazyViewpointFactory.this.getClass();\r
  55             }\r
  56         };\r
  57     }\r
  58 \r
  59     abstract protected Collection<?> getChildren(ReadGraph g, NodeContext context) throws DatabaseException;\r
  60 \r
  61     protected boolean hasChildren(ReadGraph g, NodeContext context) throws DatabaseException {\r
  62         return !getChildren(g, context).isEmpty();\r
  63     }\r
  64 \r
  65 }\r