Copyright (c) 2009, 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 Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2009, 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 Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.core.internal.preferences;

import java.util.*;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;
import org.eclipse.core.runtime.preferences.*;

This class represents a preference node in the "bundle_defaults" scope. This scope is
used to represent default values which are set by the bundle in either its preference
initializer or in a file included with the bundle.
This differs from the regular default scope because it does not contain values set
by the product preference customization or the command-line.
Since:
3.3/**
 * This class represents a preference node in the "bundle_defaults" scope. This scope is
 * used to represent default values which are set by the bundle in either its preference
 * initializer or in a file included with the bundle.
 *
 * This differs from the regular default scope because it does not contain values set
 * by the product preference customization or the command-line.
 *
 * @since 3.3
 */
public class BundleDefaultPreferences extends EclipsePreferences {

	private static Set<String> loadedNodes = Collections.synchronizedSet(new HashSet<String>());
	private String qualifier;
	private int segmentCount;
	private IEclipsePreferences loadLevel;

	/*
	 * Default constructor.
	 */
	public BundleDefaultPreferences() {
		this(null, null);
	}

	private BundleDefaultPreferences(EclipsePreferences parent, String name) {
		super(parent, name);
		// cache the segment count
		IPath path = new Path(absolutePath());
		segmentCount = path.segmentCount();
		if (segmentCount < 2)
			return;

		// cache the qualifier
		String scope = path.segment(0);
		if (BundleDefaultsScope.SCOPE.equals(scope))
			qualifier = path.segment(1);

		// cache the location
		if (qualifier == null)
			return;
	}


	@Override
	protected IEclipsePreferences getLoadLevel() {
		if (loadLevel == null) {
			if (qualifier == null)
				return null;
			// Make it relative to this node rather than navigating to it from the root.
			// Walk backwards up the tree starting at this node.
			// This is important to avoid a chicken/egg thing on startup.
			IEclipsePreferences node = this;
			for (int i = 2; i < segmentCount; i++)
				node = (IEclipsePreferences) node.parent();
			loadLevel = node;
		}
		return loadLevel;
	}


	@Override
	protected boolean isAlreadyLoaded(IEclipsePreferences node) {
		return loadedNodes.contains(node.name());
	}


	@Override
	protected void loaded() {
		loadedNodes.add(name());
	}


	@Override
	protected void load() {
		// ensure that the same node in the "default" scope is loaded so this one is
		// initialized properly
		String relativePath = DefaultPreferences.getScopeRelativePath(absolutePath());
		if (relativePath != null) {
			// touch the node to force a load
			PreferencesService.getDefault().getRootNode().node(DefaultScope.SCOPE).node(relativePath);
		}
	}


	@Override
	protected EclipsePreferences internalCreate(EclipsePreferences nodeParent, String nodeName, Object context) {
		return new BundleDefaultPreferences(nodeParent, nodeName);
	}
}