bundles/org.simantics.browsing.ui.graph.impl/src/org/simantics/browsing/ui/graph/impl/LazyParametrizedViewpoint.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.function.Consumer;\r
  15 \r
  16 import org.simantics.browsing.ui.BuiltinKeys;\r
  17 import org.simantics.browsing.ui.DataSource;\r
  18 import org.simantics.browsing.ui.NodeContext;\r
  19 import org.simantics.browsing.ui.PrimitiveQueryUpdater;\r
  20 import org.simantics.browsing.ui.common.viewpoints.ViewpointStub;\r
  21 import org.simantics.browsing.ui.content.Viewpoint;\r
  22 import org.simantics.browsing.ui.graph.impl.request.ParametrizedResourceQuery;\r
  23 import org.simantics.db.ReadGraph;\r
  24 import org.simantics.db.exception.DatabaseException;\r
  25 import org.simantics.db.procedure.Listener;\r
  26 import org.simantics.utils.datastructures.Pair;\r
  27 \r
  28 /**\r
  29  * Implement {@link #children(ReadGraph)} and {@link #hasChildren(ReadGraph)}.\r
  30  * \r
  31  * @author Tuukka Lehtonen\r
  32  */\r
  33 public abstract class LazyParametrizedViewpoint extends ViewpointStub {\r
  34 \r
  35         /**\r
  36          * Needed for separating childQuery and hasChildQuery from each other in the\r
  37          * equals sense.\r
  38          */\r
  39         private static final Object                              CHILDREN     = new Object();\r
  40         private static final Object                              HAS_CHILDREN = new Object();\r
  41 \r
  42         private final ParametrizedResourceQuery<NodeContext[]> childQuery;\r
  43         private final ParametrizedResourceQuery<Boolean>        hasChildQuery;\r
  44 \r
  45     private final Listener<NodeContext[]>              childQueryProcedure;\r
  46     private final Listener<Boolean>                     hasChildQueryProcedure;\r
  47 \r
  48     private final PrimitiveQueryUpdater                      updater;\r
  49     private final NodeContext                               context;\r
  50     private final BuiltinKeys.ViewpointKey                   key;\r
  51 \r
  52         /**\r
  53          * @return\r
  54          */\r
  55         public abstract NodeContext[] children(ReadGraph graph) throws DatabaseException;\r
  56 \r
  57         /**\r
  58          * @param graph\r
  59          * @return\r
  60          */\r
  61         public abstract Boolean hasChildren(ReadGraph graph) throws DatabaseException;\r
  62 \r
  63 \r
  64         public LazyParametrizedViewpoint(PrimitiveQueryUpdater updater, NodeContext context, BuiltinKeys.ViewpointKey key, Object... parameters) {\r
  65                 assert updater != null;\r
  66                 assert context != null;\r
  67                 assert key != null;\r
  68 \r
  69                 this.updater = updater;\r
  70                 this.context = context;\r
  71                 this.key = key;\r
  72 \r
  73                 this.childQuery = new ParametrizedResourceQuery<NodeContext[]>(Pair.make(getClass(), CHILDREN), context, parameters) {\r
  74 \r
  75                         @Override\r
  76                         public NodeContext[] perform(ReadGraph graph) throws DatabaseException {\r
  77                                 return  children(graph);\r
  78                         }\r
  79 \r
  80                 };\r
  81 \r
  82                 this.childQueryProcedure = new Listener<NodeContext[]>() {\r
  83 \r
  84                         @Override\r
  85                         public void execute(NodeContext[] result) {\r
  86                                 replaceChildrenResult(result);\r
  87                         }\r
  88 \r
  89                         @Override\r
  90                         public boolean isDisposed() {\r
  91                                 return LazyParametrizedViewpoint.this.updater.isDisposed();\r
  92                         }\r
  93 \r
  94                         public void exception(Throwable t) {\r
  95                                 System.out.print("LazyParametrizedViewpoint2.childQuery failed: ");\r
  96                                 t.printStackTrace();\r
  97                         }\r
  98 \r
  99                 };\r
 100 \r
 101                 this.hasChildQuery = new ParametrizedResourceQuery<Boolean>(Pair.make(getClass(), HAS_CHILDREN), context, parameters) {\r
 102 \r
 103                         @Override\r
 104                         public Boolean perform(ReadGraph graph) throws DatabaseException {\r
 105                                 return hasChildren(graph);\r
 106                         }\r
 107 \r
 108                 };\r
 109 \r
 110                 this.hasChildQueryProcedure = new Listener<Boolean>() {\r
 111 \r
 112                         @Override\r
 113                         public void execute(Boolean result) {\r
 114                                 replaceHasChildrenResult(result);\r
 115                         }\r
 116 \r
 117                         @Override\r
 118                         public boolean isDisposed() {\r
 119                                 return LazyParametrizedViewpoint.this.updater.isDisposed();\r
 120                         }\r
 121 \r
 122                         public void exception(Throwable t) {\r
 123                                 System.out.print("LazyParametrizedViewpoint2.hasChildQuery failed: ");\r
 124                                 t.printStackTrace();\r
 125                         }\r
 126 \r
 127                 };\r
 128 \r
 129         }\r
 130 \r
 131         public NodeContext getContext() {\r
 132                 return context;\r
 133         }\r
 134 \r
 135         @Override\r
 136         public NodeContext[] getChildren() {\r
 137                 if (children == Viewpoint.PENDING_CHILDREN) {\r
 138                         DataSource<ReadGraph> source = updater.getDataSource(ReadGraph.class);\r
 139                         if (source != null) {\r
 140                                 source.schedule(graph -> graph.asyncRequest(childQuery, childQueryProcedure));\r
 141                         }\r
 142                 }\r
 143 \r
 144                 return children;\r
 145         }\r
 146 \r
 147         @Override\r
 148         public Boolean getHasChildren() {\r
 149                 if (hasChildren == Viewpoint.PENDING_HAS_CHILDREN) {\r
 150                         DataSource<ReadGraph> source = updater.getDataSource(ReadGraph.class);\r
 151                         if (source != null) {\r
 152                                 source.schedule(new Consumer<ReadGraph>() {\r
 153                                         @Override\r
 154                                         public void accept(ReadGraph source) {\r
 155                                                 source.asyncRequest(hasChildQuery, hasChildQueryProcedure);\r
 156                                         }\r
 157                                 });\r
 158                         }\r
 159                 }\r
 160 \r
 161                 return hasChildren;\r
 162         }\r
 163 \r
 164         protected void replaceChildrenResult(NodeContext[] result) {\r
 165                 setChildren(updater, result);\r
 166                 updater.scheduleReplace(context, key, this);\r
 167         }\r
 168 \r
 169         protected void replaceHasChildrenResult(Boolean result) {\r
 170                 setHasChildren(result);\r
 171                 updater.scheduleReplace(context, key, this);\r
 172         }\r
 173 \r
 174         /**\r
 175          * @param <T>\r
 176          * @param clazz\r
 177          * @return input of the specified class\r
 178          * @throws ClassCastException if the input class does not match the\r
 179          *         specified class\r
 180          * @throws NullPointerException if the input is null\r
 181          */\r
 182          protected <T> T getInput(Class<T> clazz) throws ClassCastException {\r
 183                  Object o = context.getConstant(BuiltinKeys.INPUT);\r
 184                  if (o == null)\r
 185                          throw new NullPointerException("null input");\r
 186                  return clazz.cast(o);\r
 187          }\r
 188 \r
 189          /**\r
 190           * @param <T>\r
 191           * @param clazz\r
 192           * @return <code>null</code> if input is <code>null</code> or if the class does not match\r
 193           */\r
 194          protected <T> T tryGetInput(Class<T> clazz) {\r
 195                  Object o = context.getConstant(BuiltinKeys.INPUT);\r
 196                  if (o != null && clazz.isInstance(o))\r
 197                          return clazz.cast(o);\r
 198                  return null;\r
 199          }\r
 200 \r
 201 }\r