| /******************************************************************************* |
| * Copyright (c) 2005, 2018 IBM Corporation and others. |
| * 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: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.jface.examples.databinding.contentprovider.test; |
| |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.HashSet; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.Random; |
| import java.util.Set; |
| |
| import org.eclipse.core.databinding.observable.Diffs; |
| import org.eclipse.core.databinding.observable.set.ObservableSet; |
| import org.eclipse.swt.widgets.Display; |
| |
| /** |
| * Test set that simulates asynchronously computed elements. The elements of the |
| * set are randomly generated Integers. Whenever the "recompute" method is |
| * called, the set will spin off a job that sleeps for a period of time and then |
| * randomly adds and removes elements from the set. |
| * |
| * <p> |
| * This simulates a set that wraps a database query or network communication. |
| * These would follow the same pattern (report the set as "stale", perform some |
| * slow operation, then make changes to the set). |
| * </p> |
| * |
| * @since 1.0 |
| */ |
| public class AsynchronousTestSet extends ObservableSet<Object> { |
| |
| private static Random randomNumberGenerator = new Random(); |
| |
| private Display display; |
| |
| private boolean stale = false; |
| |
| /** |
| * Average number of elements to add or remove |
| */ |
| private static final int AVERAGE_DELTA = 4; |
| |
| /** |
| * Average "computation" time -- time taken to do the simulated work (ms) |
| */ |
| private static final int AVERAGE_BUSY_TIME = 1000; |
| |
| /** |
| * List of all undisposed AsynchronousTestSet instances. Used for the |
| * recomputeAll method. |
| */ |
| private static List<Object> allSets = new ArrayList<>(); |
| |
| public AsynchronousTestSet() { |
| super(new HashSet<>(), Object.class); |
| display = Display.getCurrent(); |
| if (display == null) { |
| throw new IllegalStateException( |
| "This object can only be created in the UI thread"); //$NON-NLS-1$ |
| } |
| recompute(); |
| } |
| |
| @Override |
| protected void firstListenerAdded() { |
| super.firstListenerAdded(); |
| allSets.add(this); |
| } |
| |
| @Override |
| protected void lastListenerRemoved() { |
| allSets.remove(this); |
| super.lastListenerRemoved(); |
| } |
| |
| public static void recomputeAll() { |
| for (Iterator<Object> iter = allSets.iterator(); iter.hasNext();) { |
| AsynchronousTestSet next = (AsynchronousTestSet) iter.next(); |
| |
| next.recompute(); |
| } |
| } |
| |
| public void remove(Collection<Object> toRemove) { |
| Set<Object> removed = new HashSet<>(); |
| removed.addAll(toRemove); |
| removed.retainAll(wrappedSet); |
| |
| wrappedSet.removeAll(removed); |
| fireSetChange(Diffs.createSetDiff(Collections.EMPTY_SET, removed)); |
| } |
| |
| @Override |
| public boolean isStale() { |
| return stale; |
| } |
| |
| public void recompute() { |
| if (!isStale()) { |
| setStale(true); |
| final int sleepTime = (int) (randomNumberGenerator.nextDouble() * (AVERAGE_BUSY_TIME * 2)); |
| Thread newThread = new Thread(() -> { |
| |
| // Simulate work by sleeping |
| try { |
| Thread.sleep(sleepTime); |
| } catch (InterruptedException e) { |
| } |
| |
| // Add and remove some elements -- important: fire all |
| // events in the UI thread |
| display.asyncExec(() -> { |
| final Set<Object> toAdd = new HashSet<>(); |
| final Set<Object> toRemove = new HashSet<>(); |
| |
| // Compute elements to add and remove (basically |
| // just fills the toAdd |
| // and toRemove sets with random elements) |
| int delta = (randomNumberGenerator.nextInt(AVERAGE_DELTA * 4) - AVERAGE_DELTA * 2); |
| int extraAdds = randomNumberGenerator.nextInt(AVERAGE_DELTA); |
| int addCount = delta + extraAdds; |
| int removeCount = -delta + extraAdds; |
| |
| if (addCount > 0) { |
| for (int i1 = 0; i1 < addCount; i1++) { |
| toAdd.add(Integer.valueOf(randomNumberGenerator.nextInt(20))); |
| } |
| } |
| |
| if (removeCount > 0) { |
| Iterator<Object> oldElements = wrappedSet.iterator(); |
| for (int i2 = 0; i2 < removeCount && oldElements.hasNext(); i2++) { |
| toRemove.add(oldElements.next()); |
| } |
| } |
| |
| toAdd.removeAll(wrappedSet); |
| wrappedSet.addAll(toAdd); |
| wrappedSet.removeAll(toRemove); |
| |
| setStale(false); |
| fireSetChange(Diffs.createSetDiff(toAdd, toRemove)); |
| }); |
| }); |
| |
| newThread.start(); |
| } |
| } |
| } |