bundles/org.simantics.db.impl/src/org/simantics/db/impl/query/AsyncReadEntry.java

   1 /*******************************************************************************
   2  * Copyright (c) 2007, 2010 Association for Decentralized Information Management
   3  * in Industry THTH ry.
   4  * All rights reserved. This program and the accompanying materials
   5  * are made available under the terms of the Eclipse Public License v1.0
   6  * which accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *     VTT Technical Research Centre of Finland - initial API and implementation
  11  *******************************************************************************/
  12 package org.simantics.db.impl.query;
  13
  14 import org.simantics.db.AsyncReadGraph;
  15 import org.simantics.db.exception.DatabaseException;
  16 import org.simantics.db.impl.DebugPolicy;
  17 import org.simantics.db.impl.graph.ReadGraphImpl;
  18 import org.simantics.db.procedure.AsyncProcedure;
  19 import org.simantics.db.request.AsyncRead;
  20
  21 final public class AsyncReadEntry<T> extends CacheEntryBase<AsyncProcedure<T>> {
  22
  23     protected AsyncRead<T> request;
  24
  25     AsyncReadEntry(AsyncRead<T> request) {
  26         this.request = request;
  27         if(DebugPolicy.QUERY_STATE) System.out.println("[QUERY STATE]: created " + this);
  28     }
  29
  30     @Override
  31     int makeHash() {
  32         return request.hashCode();
  33     }
  34
  35     @Override
  36     public Object getOriginalRequest() {
  37         return request;
  38     }
  39
  40     @Override
  41     public void discard() {
  42         super.discard();
  43         setResult(null);
  44     }
  45
  46     final public void addOrSet(AsyncReadGraph graph, Object item) {
  47
  48         assert(isPending());
  49
  50         synchronized(this) {
  51             setResult(item);
  52                 setReady();
  53         }
  54
  55     }
  56
  57
  58     public void except(AsyncReadGraph graph, Throwable t) {
  59
  60         assert(isPending());
  61
  62         synchronized(this) {
  63             except(t);
  64         }
  65
  66     }
  67
  68
  69     @Override
  70     final public Query getQuery() {
  71
  72         return new Query() {
  73
  74                         @Override
  75                         public void recompute(ReadGraphImpl graph) {
  76
  77                                 try {
  78
  79                                     request.perform(graph , new AsyncProcedure<T>() {
  80
  81                         @Override
  82                         public void execute(AsyncReadGraph graph, T result) {
  83                             addOrSet(graph, result);
  84                         }
  85
  86                                 @Override
  87                                 public void exception(AsyncReadGraph graph, Throwable t) {
  88                                     except(t);
  89                         }
  90
  91                     });
  92
  93                                 } catch (Throwable t) {
  94                                     except(t);
  95                 }
  96
  97                         }
  98
  99                         @Override
 100                         public void removeEntry(QueryProcessor qp) {
 101                         qp.cache.remove(AsyncReadEntry.this);
 102                         }
 103
 104                         @Override
 105                         public int type() {
 106                                 return request.getFlags();
 107                         }
 108
 109                         @Override
 110                         public String toString() {
 111                                 if(request == null) return "DISCARDED";
 112                                 else if(isExcepted()) return request.toString() + " " + getResult();
 113                                 else return request.toString() + " " + statusOrException;
 114                         }
 115
 116         };
 117
 118     }
 119
 120     @Override
 121         public Object performFromCache(ReadGraphImpl graph, AsyncProcedure<T> proc) {
 122
 123             if(isExcepted()) {
 124
 125             try {
 126                 proc.exception(graph, (Throwable)getResult());
 127             } catch (Throwable t) {
 128                 t.printStackTrace();
 129             }
 130
 131         } else {
 132
 133             try {
 134                 proc.execute(graph, (T)getResult());
 135             } catch (Throwable t) {
 136                 t.printStackTrace();
 137             }
 138
 139         }
 140
 141             return getResult();
 142
 143         }
 144
 145     @Override
 146     public Object compute(ReadGraphImpl graph, AsyncProcedure<T> procedure) throws DatabaseException {
 147         return graph.processor.cache.performQuery(graph, request, this, procedure);
 148     }
 149
 150         @Override
 151         public String toString() {
 152                 if(isDiscarded()) return "DISCARDED " + request.toString();
 153                 else if(isExcepted()) return request.toString() + " " + getResult();
 154                 else return request.toString() + " " + statusOrException;
 155         }
 156
 157 }