Copyright (c) 2004, 2015 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM - Initial API and implementation
/*******************************************************************************
 * Copyright (c) 2004, 2015 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM - Initial API and implementation
 *******************************************************************************/
package org.eclipse.core.internal.refresh;

import org.eclipse.core.internal.resources.IManager;
import org.eclipse.core.internal.utils.Messages;
import org.eclipse.core.resources.*;
import org.eclipse.core.resources.refresh.IRefreshMonitor;
import org.eclipse.core.resources.refresh.IRefreshResult;
import org.eclipse.core.runtime.*;
import org.eclipse.core.runtime.Preferences.PropertyChangeEvent;

Manages auto-refresh functionality, including maintaining the active
set of monitors and controlling the job that performs periodic refreshes
on out of sync resources.
Since:
3.0/**
 * Manages auto-refresh functionality, including maintaining the active
 * set of monitors and controlling the job that performs periodic refreshes
 * on out of sync resources.
 *
 * @since 3.0
 */
public class RefreshManager implements IRefreshResult, IManager, Preferences.IPropertyChangeListener {
	public static final String DEBUG_PREFIX = "Auto-refresh: "; //$NON-NLS-1$
	MonitorManager monitors;
	private RefreshJob refreshJob;

	
The workspace.
/**
	 * The workspace.
	 */
	private IWorkspace workspace;

	public RefreshManager(IWorkspace workspace) {
		this.workspace = workspace;
	}

	/*
	 * Starts or stops auto-refresh depending on the auto-refresh preference.
	 */
	protected void manageAutoRefresh(boolean enabled, IProgressMonitor progressMonitor) {
		//do nothing if we have already shutdown
		if (refreshJob == null) {
			return;
		}
		SubMonitor subMonitor = SubMonitor.convert(progressMonitor, 1);
		if (enabled) {
			refreshJob.start();
			monitors.start(subMonitor.split(1));
		} else {
			refreshJob.stop();
			monitors.stop();
		}
	}

	@Override
	public void monitorFailed(IRefreshMonitor monitor, IResource resource) {
		monitors.monitorFailed(monitor, resource);
	}

	
Checks for changes to the PREF_AUTO_UPDATE property.
See Also:
propertyChange.propertyChange(PropertyChangeEvent)/**
	 * Checks for changes to the PREF_AUTO_UPDATE property.
	 * @see org.eclipse.core.runtime.Preferences.IPropertyChangeListener#propertyChange(Preferences.PropertyChangeEvent)
	 */
	@Deprecated
	@Override
	public void propertyChange(PropertyChangeEvent event) {
		String property = event.getProperty();
		if (ResourcesPlugin.PREF_AUTO_REFRESH.equals(property)) {
			Preferences preferences = ResourcesPlugin.getPlugin().getPluginPreferences();
			final boolean autoRefresh = preferences.getBoolean(ResourcesPlugin.PREF_AUTO_REFRESH);
			String jobName = autoRefresh ? Messages.refresh_installMonitorsOnWorkspace : Messages.refresh_uninstallMonitorsOnWorkspace;
			MonitorJob.createSystem(jobName, ResourcesPlugin.getWorkspace().getRoot(), (ICoreRunnable) monitor -> manageAutoRefresh(autoRefresh, monitor)).schedule();
		}
	}

	@Override
	public void refresh(IResource resource) {
		//do nothing if we have already shutdown
		if (refreshJob != null)
			refreshJob.refresh(resource);
	}

	
Shuts down the refresh manager.  This only happens when
the resources plugin is going away.
/**
	 * Shuts down the refresh manager.  This only happens when
	 * the resources plugin is going away.
	 */
	@Override
	public void shutdown(IProgressMonitor monitor) {
		ResourcesPlugin.getPlugin().getPluginPreferences().removePropertyChangeListener(this);
		if (monitors != null) {
			monitors.stop();
			monitors = null;
		}
		if (refreshJob != null) {
			refreshJob.stop();
			refreshJob = null;
		}
	}

	
Initializes the refresh manager. This does a minimal amount of work
if auto-refresh is turned off.
/**
	 * Initializes the refresh manager. This does a minimal amount of work
	 * if auto-refresh is turned off.
	 */
	@Override
	public void startup(IProgressMonitor monitor) {
		SubMonitor subMonitor = SubMonitor.convert(monitor, 1);
		Preferences preferences = ResourcesPlugin.getPlugin().getPluginPreferences();
		preferences.addPropertyChangeListener(this);

		refreshJob = new RefreshJob();
		monitors = new MonitorManager(workspace, this);
		boolean autoRefresh = preferences.getBoolean(ResourcesPlugin.PREF_AUTO_REFRESH);
		if (autoRefresh)
			manageAutoRefresh(autoRefresh, subMonitor.split(1));
	}
}