/*******************************************************************************
* Copyright (c) 2006 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.ui.internal.cheatsheets.composite.model;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import org.eclipse.ui.internal.provisional.cheatsheets.ICompositeCheatSheetTask;
public class BlockedTaskFinder {
private Set stateChangedTasks;
private Set impactedTasks;
/**
* Find which tasks have either become blocked or unblocked so that they
* can be added to the list of change events.
* @param stateChangedTasks The set of tasks which has changed
* @return The set of tasks which have become blocked or unblocked by the
* change of state and were not in the original set. The algorithm will sometimes add tasks to
* the result set which were not actually impacted but this is not a major problem
* since it only means that extra events get sent to the explorer. For updates other
* than resets the number of extra events is very low.
*
* This takes several steps.
* <li> If a group is completed, skipped or reset add any non-started children.
* <li> Determine all successors of tasks whose state has changed that are not in the change set
* <li> Add the successor and its children to the list if not started
*/
public Set findBlockedTaskChanges(Set stateChangedTasks) {
this.stateChangedTasks = stateChangedTasks;
impactedTasks = new HashSet();
visitChangedTasks();
findSuccesors();
return impactedTasks;
}
private void visitChangedTasks() {
for (Iterator iter = stateChangedTasks.iterator(); iter.hasNext(); ) {
final ICompositeCheatSheetTask nextTask = (ICompositeCheatSheetTask)iter.next();
if (nextTask.getState() != ICompositeCheatSheetTask.IN_PROGRESS) {
findUnstartedChildren(nextTask);
}
}
}
/*
* Look for children which we have not seen elsewhere and if they are not started
* add them to the list of impacted tasks.
*/
private void findUnstartedChildren(ICompositeCheatSheetTask task) {
ICompositeCheatSheetTask[] children = task.getSubtasks();
for (int i = 0; i < children.length; i++) {
ICompositeCheatSheetTask nextChild = children[i];
// Ignore if this task has been seen before
if ((!stateChangedTasks.contains(nextChild)) && !impactedTasks.contains(nextChild)) {
if (nextChild.getState() == ICompositeCheatSheetTask.NOT_STARTED) {
impactedTasks.add(nextChild);
}
findUnstartedChildren(nextChild);
}
}
}
private void findSuccesors() {
for (Iterator iter = stateChangedTasks.iterator(); iter.hasNext(); ) {
final AbstractTask nextTask = (AbstractTask)iter.next();
ICompositeCheatSheetTask[] successors = nextTask.getSuccessorTasks();
for (int i = 0; i < successors.length; i++) {
ICompositeCheatSheetTask nextSuccessor = successors[i];
if (nextSuccessor.getState() == ICompositeCheatSheetTask.NOT_STARTED) {
impactedTasks.add(nextSuccessor);
}
findUnstartedChildren(nextSuccessor);
}
}
}
}