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[simantics/district.git] / org.simantics.district.maps / src / org / simantics / maps / pojo / TileJob.java

diff --git a/org.simantics.district.maps/src/org/simantics/maps/pojo/TileJob.java b/org.simantics.district.maps/src/org/simantics/maps/pojo/TileJob.java
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+/*******************************************************************************
+ * Copyright (c) 2012 Association for Decentralized Information Management
+ * in Industry THTH ry.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     VTT Technical Research Centre of Finland - initial API and implementation
+ *******************************************************************************/
+package org.simantics.maps.pojo;
+
+import java.awt.Image;
+import java.util.LinkedList;
+import java.util.concurrent.Executor;
+import java.util.concurrent.ScheduledThreadPoolExecutor;
+
+import org.simantics.maps.ProvisionException;
+import org.simantics.maps.query.Query;
+import org.simantics.maps.tile.IFilter;
+import org.simantics.maps.tile.ITileProvider;
+import org.simantics.maps.tile.TileKey;
+
+/**
+ * @author Tuukka Lehtonen
+ * @see TileJobQueue
+ */
+public class TileJob implements Runnable {
+
+    LinkedList<Query<TileKey, Image>> queue = new LinkedList<Query<TileKey, Image>>();
+    Executor executor = new ScheduledThreadPoolExecutor(1);
+    ITileProvider provider;
+
+    public TileJob() {
+    }
+
+    public void setTileProvider(ITileProvider provider) {
+        this.provider = provider;
+    }
+
+    protected Image doQuery(TileKey key) throws ProvisionException {
+        return provider.get(key);
+    }
+
+    public void run() {
+        Query<TileKey, Image> job = pullNextJob();
+        do {
+            if (job != null) {
+                try {
+                    Image result = doQuery(job.source);
+                    job.listener.queryComplete(job, result);
+                } catch (Exception e) {
+                    job.listener.queryFailed(job, e);
+                }
+            }
+            // 4. Pick next job
+            job = pullNextJob();
+        } while (job != null);
+    }
+
+    protected synchronized int jobsLeft() {
+        return queue.size();
+    }
+
+    protected synchronized Query<TileKey, Image> pullNextJob() {
+        if (queue.isEmpty())
+            return null;
+        return queue.removeFirst();
+    }
+
+    public synchronized void clear() {
+        @SuppressWarnings("unchecked")
+        Query<TileKey, Image> jobs[] = queue.toArray(new Query[queue.size()]);
+        for (Query<TileKey, Image> j : jobs)
+            removeJob(j);
+    }
+
+    public synchronized void addJob(Query<TileKey, Image> job) {
+        queue.addLast(job);
+        if (queue.size() == 1) {
+            executor.execute(this);
+        }
+    }
+
+    public synchronized void addAsFirstJob(Query<TileKey, Image> job) {
+        queue.addFirst(job);
+        if (queue.size() == 1) {
+            executor.execute(this);
+        }
+    }
+
+    public synchronized boolean removeJob(Query<TileKey, Image> job) {
+        if (queue.remove(job)) {
+            job.listener.queryCanceled(job);
+            return true;
+        }
+        return false;
+    }
+
+    public synchronized void filterQueries(IFilter<TileKey> filter) {
+        if (queue.isEmpty())
+            return;
+
+        LinkedList<Query<TileKey, Image>> result = new LinkedList<Query<TileKey, Image>>();
+        for (Query<TileKey, Image> query : queue) {
+            if (filter.select(query.source))
+                result.add(query);
+            else
+                query.listener.queryCanceled(query);
+        }
+        this.queue = result;
+    }
+
+}