bundles/org.simantics.db.impl/src/org/simantics/db/impl/query/ValueQuery.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 java.util.concurrent.Semaphore;
  15
  16 import org.simantics.db.impl.graph.ReadGraphImpl;
  17 import org.simantics.db.impl.procedure.InternalProcedure;
  18 import org.simantics.db.procedure.ListenerBase;
  19
  20 final public class ValueQuery extends UnaryQuery<InternalProcedure<byte[]>> {
  21
  22     private ValueQuery(final int resource) {
  23         super(resource);
  24     }
  25
  26     final static ValueQuery entry(final QueryProcessor provider, final int r) {
  27         return (ValueQuery)provider.valueMap.get(r);
  28     }
  29
  30     final static byte[] runner(final ReadGraphImpl graph, final int r, CacheEntry parent, final ListenerBase listener, final InternalProcedure<byte[]> procedure) {
  31
  32         QueryProcessor processor = graph.processor;
  33
  34         ValueQuery entry = (ValueQuery)processor.valueMap.get(r);
  35         if(entry == null) {
  36
  37                 entry = new ValueQuery(r);
  38                 entry.setPending();
  39                 entry.clearResult(processor.querySupport);
  40                 entry.putEntry(processor);
  41
  42                 return (byte[])processor.performForEach(graph, entry, parent, listener, procedure);
  43
  44         } else {
  45
  46                 return (byte[])processor.performForEach(graph, entry, parent, listener, procedure);
  47
  48         }
  49
  50     }
  51
  52     final public static byte[] queryEach(ReadGraphImpl graph, final int r, final CacheEntry parent, final ListenerBase listener, final InternalProcedure<byte[]> procedure) {
  53
  54         assert(r != 0);
  55
  56         if(graph.parent == null && listener == null) {
  57                 return ValueQuery.computeForEach(graph, r, null, procedure);
  58         } else {
  59                 return runner(graph, r, parent, listener, procedure);
  60         }
  61
  62     }
  63
  64     final public static byte[] queryEach(ReadGraphImpl graph, final int r, final CacheEntry parent) {
  65
  66         assert(r != 0);
  67
  68         if(graph.parent == null) {
  69             return ValueQuery.computeForEach(graph, r);
  70         } else {
  71             return runner(graph, r, parent, null, null);
  72         }
  73
  74     }
  75
  76         @Override
  77         public UnaryQuery<InternalProcedure<byte[]>> getEntry(QueryProcessor provider) {
  78         return provider.valueMap.get(id);
  79         }
  80
  81         @Override
  82         public void putEntry(QueryProcessor provider) {
  83         provider.valueMap.put(id, this);
  84         }
  85
  86         @Override
  87         final public void removeEntry(QueryProcessor provider) {
  88                 provider.valueMap.remove(id);
  89         }
  90
  91
  92         public static byte[] computeForEach(ReadGraphImpl graph, final int r, final ValueQuery entry, final InternalProcedure<byte[]> procedure) {
  93
  94                 graph.ensureLoaded(r);
  95
  96                 byte[] value = graph.getValue(r);
  97                 if(entry != null) {
  98                         entry.setResult(value);
  99                         entry.setReady();
 100                 }
 101                 if(procedure != null) {
 102                         procedure.execute(graph, value);
 103                 }
 104
 105                 return value;
 106
 107         }
 108
 109     public static byte[] computeForEach(ReadGraphImpl graph, final int r) {
 110
 111         graph.ensureLoaded(r);
 112
 113         return graph.getValue(r);
 114
 115     }
 116
 117         @Override
 118         public Object computeForEach(ReadGraphImpl graph, final QueryProcessor queryProvider, final InternalProcedure<byte[]> procedure, final boolean store) {
 119                 return computeForEach(graph, id, this, procedure);
 120     }
 121
 122     @Override
 123     public String toString() {
 124         return "Value[" + id + "]";
 125     }
 126
 127     @Override
 128     public Object performFromCache(ReadGraphImpl graph, QueryProcessor queryProvider, InternalProcedure<byte[]> procedure) {
 129         return computeForEach(graph, queryProvider, procedure, false);
 130     }
 131
 132     @Override
 133     public void recompute(ReadGraphImpl graph, QueryProcessor provider) {
 134
 135         final Semaphore s = new Semaphore(0);
 136
 137         computeForEach(graph, provider, new InternalProcedure<byte[]>() {
 138
 139             @Override
 140             public void execute(ReadGraphImpl graph, byte[] result) {
 141                 s.release();
 142             }
 143
 144                         @Override
 145                         public void exception(ReadGraphImpl graph, Throwable t) {
 146                                 throw new Error("Error in recompute.", t);
 147             }
 148
 149         }, true);
 150
 151         while(!s.tryAcquire()) {
 152                 provider.resume(graph);
 153         }
 154
 155     }
 156
 157     @Override
 158     boolean isImmutable(ReadGraphImpl graph) {
 159         return graph.processor.isImmutable(id);
 160     }
 161
 162 }