1 /*******************************************************************************
2 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
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
10 * VTT Technical Research Centre of Finland - initial API and implementation
11 *******************************************************************************/
12 package org.simantics.db.impl.query;
14 import java.util.ArrayList;
15 import java.util.LinkedList;
17 import org.simantics.db.impl.graph.ReadGraphImpl;
18 import org.simantics.db.procedure.Procedure;
19 import org.simantics.db.request.ExternalRead;
20 import org.simantics.db.request.RequestFlags;
22 final public class ExternalReadEntry<T> extends CacheEntryBase {
24 final LinkedList<T> items = new LinkedList<T>();
26 // public ArrayList<Procedure<T>> procs;
28 protected ExternalRead<T> request;
32 return request.hashCode();
36 public Object getOriginalRequest() {
41 public void clearResult(QuerySupport support) {
45 public void discard() {
46 request.unregistered();
51 public ExternalReadEntry(ExternalRead<T> request) {
52 assert request != null;
53 this.request = request;
56 final public void queue(T item) {
59 // TODO: implement flags/logic in ExternalRead to state that all but the latest request result can be evaporated
60 // In some cases where data is produced really fast this might be necessary but currently this queueing will do.
64 final public void addOrSet(QueryProcessor processor, Object item) {
70 ArrayList<Procedure<T>> p = null;
82 // for(Procedure proc : p) {
83 // proc.execute((T)item);
86 } catch (Throwable t) {
93 final public Query getQuery() {
98 public void recompute(ReadGraphImpl graph, Object provider, CacheEntry entry) {
100 final QueryProcessor qp = (QueryProcessor)provider;
101 synchronized(items) {
103 if(entry.isExcepted()) {
105 // Exception persists
110 if(!items.isEmpty()) {
111 setResult(items.removeFirst());
114 if(!items.isEmpty()) {
115 qp.updatePrimitive(request);
127 public void removeEntry(QueryProcessor processor) {
128 processor.externalReadMap.remove(request);
133 return RequestFlags.IMMEDIATE_UPDATE;
137 public String toString() {
138 if(request == null) return "DISCARDED ExternalRead";
139 else return request.toString();
146 public void performFromCache(Object procedure) {
148 Procedure<T> proc = (Procedure<T>)procedure;
152 proc.exception((Throwable)getResult());
156 proc.execute((T)getResult());
163 public String toString() {
164 if(request == null) return "DISCARDED ExternalRead " + System.identityHashCode(this);
165 else return request.toString() + " " + + System.identityHashCode(this);
169 public void performFromCache(ReadGraphImpl graph, Object provider, Object procedure) {
170 performFromCache(procedure);
174 public void setReady() {
179 void prepareRecompute(QuerySupport querySupport) {
180 // Do nothing - the state is already set and cannot be recomputed on demand