| package org.eclipse.jface.examples.databinding.contentprovider.test; |
| |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.HashSet; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.Random; |
| import java.util.Set; |
| |
| import org.eclipse.jface.internal.databinding.swt.SWTUtil; |
| import org.eclipse.jface.internal.provisional.databinding.AbstractUpdatableSet; |
| 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 3.2 |
| */ |
| public class AsynchronousTestSet extends AbstractUpdatableSet { |
| |
| private Set elements = new HashSet(); |
| 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 allSets = new ArrayList(); |
| |
| public AsynchronousTestSet() { |
| display = Display.getCurrent(); |
| if (display == null) { |
| throw new IllegalStateException("This object can only be created in the UI thread"); |
| } |
| recompute(); |
| } |
| |
| protected Collection computeElements() { |
| return elements; |
| } |
| |
| protected void firstListenerAdded() { |
| super.firstListenerAdded(); |
| allSets.add(this); |
| } |
| |
| protected void lastListenerRemoved() { |
| allSets.remove(this); |
| super.lastListenerRemoved(); |
| } |
| |
| public static void recomputeAll() { |
| for (Iterator iter = allSets.iterator(); iter.hasNext();) { |
| AsynchronousTestSet next = (AsynchronousTestSet) iter.next(); |
| |
| next.recompute(); |
| } |
| } |
| |
| public void remove(Collection toRemove) { |
| HashSet rem = new HashSet(); |
| rem.addAll(toRemove); |
| rem.retainAll(elements); |
| |
| elements.removeAll(rem); |
| fireRemoved(rem); |
| } |
| |
| public boolean isStale() { |
| return stale; |
| } |
| |
| public void recompute() { |
| if (!isStale()) { |
| setStale(true); |
| final int sleepTime = (int)(randomNumberGenerator.nextDouble() * (double)(AVERAGE_BUSY_TIME * 2)); |
| Thread newThread = new Thread(new Runnable() { |
| public void run() { |
| |
| // Simulate work by sleeping |
| try { |
| Thread.sleep(sleepTime); |
| } catch (InterruptedException e) { |
| } |
| |
| |
| // Add and remove some elements -- important: fire all events in the UI thread |
| SWTUtil.greedyExec(display, new Runnable() { |
| public void run() { |
| final HashSet toAdd = new HashSet(); |
| final HashSet 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 i = 0; i < addCount; i++) { |
| toAdd.add(new Integer(randomNumberGenerator.nextInt(20))); |
| } |
| } |
| |
| if (removeCount > 0) { |
| Iterator oldElements = elements.iterator(); |
| for (int i = 0; i < removeCount && oldElements.hasNext(); i++) { |
| toRemove.add(oldElements.next()); |
| } |
| } |
| |
| setStale(false); |
| |
| toAdd.removeAll(elements); |
| elements.addAll(toAdd); |
| fireAdded(toAdd); |
| elements.removeAll(toRemove); |
| fireRemoved(toRemove); |
| } |
| }); |
| } |
| }); |
| |
| newThread.start(); |
| } |
| } |
| |
| private void setStale(boolean b) { |
| if (!stale == b) { |
| stale = b; |
| fireStale(b); |
| } |
| } |
| } |