bundles/org.simantics.db.impl/src/org/simantics/db/impl/BlockingAsyncProcedure.java

   1 /*******************************************************************************
   2  * Copyright (c) 2018 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  *     Semantum Oy - initial API and implementation
  11  *******************************************************************************/
  12 package org.simantics.db.impl;
  13
  14 import org.simantics.db.AsyncReadGraph;
  15 import org.simantics.db.common.utils.Logger;
  16 import org.simantics.db.exception.DatabaseException;
  17 import org.simantics.db.impl.graph.ReadGraphImpl;
  18 import org.simantics.db.procedure.AsyncProcedure;
  19
  20 public class BlockingAsyncProcedure<Result> implements AsyncProcedure<Result> {
  21
  22     private static final Object NO_RESULT = new Object();
  23
  24     private final Object key;
  25     private final ReadGraphImpl graph;
  26     private final AsyncProcedure<Result> procedure;
  27
  28     private Object result = NO_RESULT;
  29     private Throwable exception = null;
  30
  31     public BlockingAsyncProcedure(ReadGraphImpl graph, AsyncProcedure<Result> procedure, Object key) {
  32         this.procedure = procedure;
  33         this.key = key;
  34         this.graph = graph;
  35         this.graph.asyncBarrier.inc();
  36     }
  37
  38     @Override
  39     public void execute(AsyncReadGraph graph, Result result) {
  40         this.result = result;
  41         this.graph.asyncBarrier.dec();
  42         try {
  43             if(procedure != null) procedure.execute(graph, result);
  44         } catch (Throwable throwable) {
  45             Logger.defaultLogError("AsyncProcedure.execute threw for " + procedure, throwable);
  46         }
  47     }
  48
  49     @Override
  50     public void exception(AsyncReadGraph graph, Throwable t) {
  51         this.exception = t;
  52         try {
  53             if(procedure != null) procedure.exception(graph, t);
  54         } catch (Throwable throwable) {
  55             Logger.defaultLogError("AsyncProcedure.exception threw for " + procedure, throwable);
  56         } finally {
  57             this.graph.asyncBarrier.dec();
  58         }
  59     }
  60
  61     public void waitBarrier() {
  62         graph.asyncBarrier.waitBarrier(key, graph);
  63     }
  64
  65     @SuppressWarnings("unchecked")
  66     public Result get() throws DatabaseException {
  67
  68         graph.asyncBarrier.waitBarrier(key, graph);
  69
  70         if(exception != null) {
  71             if(exception instanceof DatabaseException) throw (DatabaseException)exception;
  72             throw new DatabaseException(exception);
  73         } else {
  74             return (Result)result;
  75         }
  76
  77     }
  78
  79     public boolean isDone() {
  80         return graph.asyncBarrier.get() == 0;
  81     }
  82
  83     @SuppressWarnings("unchecked")
  84     public Result getResult() {
  85         return (Result)result;
  86     }
  87
  88     public Throwable getException() {
  89         return exception;
  90     }
  91
  92     @Override
  93     public String toString() {
  94         return "." + procedure;
  95     }
  96
  97 }