bundles/org.simantics.db.impl/src/org/simantics/db/impl/query/ReadEntry.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.graph.ReadGraphImpl;
  17 import org.simantics.db.impl.graph.WriteGraphImpl;
  18 import org.simantics.db.procedure.AsyncProcedure;
  19 import org.simantics.db.request.Read;
  20 import org.simantics.db.request.ReadExt;
  21 import org.simantics.db.request.RequestFlags;
  22
  23 final public class ReadEntry<T> extends CacheEntryBase<AsyncProcedure<T>> {
  24
  25         protected Read<T> request;
  26
  27         public ReadEntry(Read<T> request) {
  28         this.request = request;
  29     }
  30
  31     @Override
  32     int makeHash() {
  33         return request.hashCode();
  34     }
  35
  36     @Override
  37     public Object getOriginalRequest() {
  38         return request;
  39     }
  40
  41     @Override
  42     public void discard() {
  43         super.discard();
  44         setResult(null);
  45     }
  46
  47     final public Object addOrSet(AsyncReadGraph graph, Object result) {
  48
  49         assert(assertPending());
  50
  51         setResult(result);
  52         setReady();
  53
  54         return result;
  55
  56     }
  57
  58     @Override
  59     final public Query getQuery() {
  60
  61         return new Query() {
  62
  63                         @Override
  64                         public void recompute(ReadGraphImpl graph) {
  65
  66                                 try {
  67
  68                                     T result = request.perform(graph);
  69                                     addOrSet(graph, result);
  70
  71                                 } catch (Throwable t) {
  72
  73                                         except(t);
  74
  75                 }
  76
  77                         }
  78
  79                         @Override
  80                         public void removeEntry(QueryProcessor processor) {
  81                                 processor.cache.remove(ReadEntry.this);
  82                         }
  83
  84                         @Override
  85                         public int type() {
  86                                 if(request instanceof ReadExt) {
  87                                         return ((ReadExt)request).getType();
  88                                 } else {
  89                                         return RequestFlags.INVALIDATE;
  90                                 }
  91                         }
  92
  93                         @Override
  94                         public String toString() {
  95                                 if(request == null) return "DISCARDED";
  96                                 else return request.toString() + statusOrException;
  97                         }
  98
  99         };
 100
 101     }
 102
 103     @Override
 104     public Object compute(ReadGraphImpl graph, AsyncProcedure<T> procedure) throws DatabaseException {
 105
 106                 ReadGraphImpl queryGraph = graph.withParent(this);
 107
 108                 try {
 109
 110                         addOrSet(queryGraph, request.perform(queryGraph));
 111                         return get(queryGraph, procedure);
 112
 113                 }  catch (DatabaseException e) {
 114
 115                         except(e);
 116                         return get(graph, procedure);
 117
 118                 }  catch (Throwable t) {
 119
 120                         except(new DatabaseException(t));
 121                         return get(graph, procedure);
 122
 123                 }
 124
 125     }
 126
 127     public static <T> void computeForEach(ReadGraphImpl graph, Read<T> request, ReadEntry<T> entry, AsyncProcedure<T> procedure) throws DatabaseException {
 128
 129                 ReadGraphImpl queryGraph = entry != null ? graph.withParent(entry) : graph;
 130
 131                 try {
 132
 133                         T result = request.perform(queryGraph);
 134                         if(entry != null) entry.addOrSet(queryGraph, result);
 135                         procedure.execute(graph, result);
 136
 137                 }  catch (DatabaseException e) {
 138
 139                         if(entry != null) entry.except(e);
 140                         procedure.exception(graph, e);
 141
 142                 }  catch (Throwable t) {
 143
 144                         DatabaseException dbe = new DatabaseException(t);
 145                         if(entry != null) entry.except(dbe);
 146                         procedure.exception(graph, dbe);
 147
 148                 }
 149
 150     }
 151
 152         public Object performFromCache(ReadGraphImpl graph, AsyncProcedure<T> procedure) {
 153
 154         AsyncProcedure<T> proc = (AsyncProcedure<T>)procedure;
 155
 156         if(proc != null) {
 157                 if(isExcepted()) {
 158                         try {
 159                                 proc.exception(graph, (Throwable)getResult());
 160                         } catch (Throwable t) {
 161                                 t.printStackTrace();
 162                         }
 163                 } else {
 164                         try {
 165                                 proc.execute(graph, (T)getResult());
 166                         } catch (Throwable t) {
 167                                 t.printStackTrace();
 168                         }
 169                 }
 170         }
 171
 172             return (T)getResult();
 173
 174         }
 175
 176         @Override
 177         public String toString() {
 178                 if(request == null) return "DISCARDED";
 179                 else return request.toString() + " - " + statusOrException;
 180         }
 181
 182         public Object get(ReadGraphImpl graph, AsyncProcedure<T> procedure) throws DatabaseException {
 183                 if(procedure != null) performFromCache(graph, procedure);
 184                 checkAndThrow();
 185                 return getResult();
 186         }
 187
 188         @Override
 189         boolean isImmutable(ReadGraphImpl graph) throws DatabaseException {
 190                 if(request instanceof ReadExt) {
 191                         return ((ReadExt)request).isImmutable(graph);
 192                 }
 193                 return false;
 194         }
 195
 196 }