MyxSubProgressMonitor.java

/*******************************************************************************
 * Copyright (c) 2000, 2007 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.archstudio.myx.fw;

/**
 * For new implementations consider using {@link SubMonitor}.
 * 
 * A progress monitor that uses a given amount of work ticks from a parent monitor. It can be used as follows:
 * 
 * <pre>
 * try {
 * 	pm.beginTask("Main Task", 100);
 * 	doSomeWork(pm, 30);
 * 	SubProgressMonitor subMonitor = new SubProgressMonitor(pm, 40);
 * 	try {
 * 		subMonitor.beginTask("", 300);
 * 		doSomeWork(subMonitor, 300);
 * 	}
 * 	finally {
 * 		subMonitor.done();
 * 	}
 * 	doSomeWork(pm, 30);
 * }
 * finally {
 * 	pm.done();
 * }
 * </pre>
 * <p>
 * This class can be used without OSGi running.
 * </p>
 * <p>
 * This class may be instantiated or subclassed by clients.
 * </p>
 * 
 * @see SubMonitor
 */
public class MyxSubProgressMonitor extends MyxProgressMonitorWrapper {

	/**
	 * Style constant indicating that calls to <code>subTask</code> should not have any effect.
	 * 
	 * @see #SubProgressMonitor(IMyxProgressMonitor,int,int)
	 */
	public static final int SUPPRESS_SUBTASK_LABEL = 1 << 1;
	/**
	 * Style constant indicating that the main task label should be prepended to the subtask label.
	 * 
	 * @see #SubProgressMonitor(IMyxProgressMonitor,int,int)
	 */
	public static final int PREPEND_MAIN_LABEL_TO_SUBTASK = 1 << 2;

	private int parentTicks = 0;
	private double sentToParent = 0.0;
	private double scale = 0.0;
	private int nestedBeginTasks = 0;
	private boolean usedUp = false;
	private boolean hasSubTask = false;
	private int style;
	private String mainTaskLabel;

	/**
	 * Creates a new sub-progress monitor for the given monitor. The sub progress monitor uses the given number of work
	 * ticks from its parent monitor.
	 * 
	 * @param monitor
	 *            the parent progress monitor
	 * @param ticks
	 *            the number of work ticks allocated from the parent monitor
	 */
	public MyxSubProgressMonitor(IMyxProgressMonitor monitor, int ticks) {
		this(monitor, ticks, 0);
	}

	/**
	 * Creates a new sub-progress monitor for the given monitor. The sub progress monitor uses the given number of work
	 * ticks from its parent monitor.
	 * 
	 * @param monitor
	 *            the parent progress monitor
	 * @param ticks
	 *            the number of work ticks allocated from the parent monitor
	 * @param style
	 *            one of
	 *            <ul>
	 *            <li> <code>SUPPRESS_SUBTASK_LABEL</code></li>
	 *            <li> <code>PREPEND_MAIN_LABEL_TO_SUBTASK</code></li>
	 *            </ul>
	 * @see #SUPPRESS_SUBTASK_LABEL
	 * @see #PREPEND_MAIN_LABEL_TO_SUBTASK
	 */
	public MyxSubProgressMonitor(IMyxProgressMonitor monitor, int ticks, int style) {
		super(monitor);
		this.parentTicks = ticks > 0 ? ticks : 0;
		this.style = style;
	}

	/*
	 * (Intentionally not javadoc'd) Implements the method <code>IMyxProgressMonitor.beginTask</code>.
	 * 
	 * Starts a new main task. Since this progress monitor is a sub progress monitor, the given name will NOT be used to
	 * update the progress bar's main task label. That means the given string will be ignored. If style
	 * <code>PREPEND_MAIN_LABEL_TO_SUBTASK <code> is specified, then the given string will be prepended to every string
	 * passed to <code>subTask(String)</code>.
	 */
	@Override
	public void beginTask(String name, int totalWork) {
		nestedBeginTasks++;
		// Ignore nested begin task calls.
		if (nestedBeginTasks > 1) {
			return;
		}
		// be safe:  if the argument would cause math errors (zero or 
		// negative), just use 0 as the scale.  This disables progress for
		// this submonitor. 
		scale = totalWork <= 0 ? 0 : (double) parentTicks / (double) totalWork;
		if ((style & PREPEND_MAIN_LABEL_TO_SUBTASK) != 0) {
			mainTaskLabel = name;
		}
	}

	/*
	 * (Intentionally not javadoc'd) Implements the method <code>IMyxProgressMonitor.done</code>.
	 */
	@Override
	public void done() {
		// Ignore if more done calls than beginTask calls or if we are still
		// in some nested beginTasks
		if (nestedBeginTasks == 0 || --nestedBeginTasks > 0) {
			return;
		}
		// Send any remaining ticks and clear out the subtask text
		double remaining = parentTicks - sentToParent;
		if (remaining > 0) {
			super.internalWorked(remaining);
		}
		//clear the sub task if there was one
		if (hasSubTask) {
			subTask(""); //$NON-NLS-1$
		}
		sentToParent = 0;
	}

	/*
	 * (Intentionally not javadoc'd) Implements the internal method <code>IMyxProgressMonitor.internalWorked</code>.
	 */
	@Override
	public void internalWorked(double work) {
		if (usedUp || nestedBeginTasks != 1) {
			return;
		}

		double realWork = work > 0.0d ? scale * work : 0.0d;
		super.internalWorked(realWork);
		sentToParent += realWork;
		if (sentToParent >= parentTicks) {
			usedUp = true;
		}
	}

	/*
	 * (Intentionally not javadoc'd) Implements the method <code>IMyxProgressMonitor.subTask</code>.
	 */
	@Override
	public void subTask(String name) {
		if ((style & SUPPRESS_SUBTASK_LABEL) != 0) {
			return;
		}
		hasSubTask = true;
		String label = name;
		if ((style & PREPEND_MAIN_LABEL_TO_SUBTASK) != 0 && mainTaskLabel != null && mainTaskLabel.length() > 0) {
			label = mainTaskLabel + ' ' + label;
		}
		super.subTask(label);
	}

	/*
	 * (Intentionally not javadoc'd) Implements the method <code>IMyxProgressMonitor.worked</code>.
	 */
	@Override
	public void worked(int work) {
		internalWorked(work);
	}
}