org.simantics.district.maps/src/org/simantics/maps/pojo/TileJob.java

   1 /*******************************************************************************
   2  * Copyright (c) 2012 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.maps.pojo;
  13
  14 import java.awt.Image;
  15 import java.util.LinkedList;
  16 import java.util.concurrent.Executor;
  17 import java.util.concurrent.ScheduledThreadPoolExecutor;
  18
  19 import org.simantics.maps.ProvisionException;
  20 import org.simantics.maps.query.Query;
  21 import org.simantics.maps.tile.IFilter;
  22 import org.simantics.maps.tile.ITileProvider;
  23 import org.simantics.maps.tile.TileKey;
  24
  25 /**
  26  * @author Tuukka Lehtonen
  27  * @see TileJobQueue
  28  */
  29 public class TileJob implements Runnable {
  30
  31     LinkedList<Query<TileKey, Image>> queue = new LinkedList<Query<TileKey, Image>>();
  32     Executor executor = new ScheduledThreadPoolExecutor(1);
  33     ITileProvider provider;
  34
  35     public TileJob() {
  36     }
  37
  38     public void setTileProvider(ITileProvider provider) {
  39         this.provider = provider;
  40     }
  41
  42     protected Image doQuery(TileKey key) throws ProvisionException {
  43         return provider.get(key);
  44     }
  45
  46     public void run() {
  47         Query<TileKey, Image> job = pullNextJob();
  48         do {
  49             if (job != null) {
  50                 try {
  51                     Image result = doQuery(job.source);
  52                     job.listener.queryComplete(job, result);
  53                 } catch (Exception e) {
  54                     job.listener.queryFailed(job, e);
  55                 }
  56             }
  57             // 4. Pick next job
  58             job = pullNextJob();
  59         } while (job != null);
  60     }
  61
  62     protected synchronized int jobsLeft() {
  63         return queue.size();
  64     }
  65
  66     protected synchronized Query<TileKey, Image> pullNextJob() {
  67         if (queue.isEmpty())
  68             return null;
  69         return queue.removeFirst();
  70     }
  71
  72     public synchronized void clear() {
  73         @SuppressWarnings("unchecked")
  74         Query<TileKey, Image> jobs[] = queue.toArray(new Query[queue.size()]);
  75         for (Query<TileKey, Image> j : jobs)
  76             removeJob(j);
  77     }
  78
  79     public synchronized void addJob(Query<TileKey, Image> job) {
  80         queue.addLast(job);
  81         if (queue.size() == 1) {
  82             executor.execute(this);
  83         }
  84     }
  85
  86     public synchronized void addAsFirstJob(Query<TileKey, Image> job) {
  87         queue.addFirst(job);
  88         if (queue.size() == 1) {
  89             executor.execute(this);
  90         }
  91     }
  92
  93     public synchronized boolean removeJob(Query<TileKey, Image> job) {
  94         if (queue.remove(job)) {
  95             job.listener.queryCanceled(job);
  96             return true;
  97         }
  98         return false;
  99     }
 100
 101     public synchronized void filterQueries(IFilter<TileKey> filter) {
 102         if (queue.isEmpty())
 103             return;
 104
 105         LinkedList<Query<TileKey, Image>> result = new LinkedList<Query<TileKey, Image>>();
 106         for (Query<TileKey, Image> query : queue) {
 107             if (filter.select(query.source))
 108                 result.add(query);
 109             else
 110                 query.listener.queryCanceled(query);
 111         }
 112         this.queue = result;
 113     }
 114
 115 }