Copyright (c) 2000, 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
    Serge Beauchamp (Freescale Semiconductor) - [229633] Group and Project Path Variable Support
    James Blackburn (Broadcom Corp.) - ongoing development
/*******************************************************************************
 * Copyright (c) 2000, 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
 *     Serge Beauchamp (Freescale Semiconductor) - [229633] Group and Project Path Variable Support
 *     James Blackburn (Broadcom Corp.) - ongoing development
 *******************************************************************************/
package org.eclipse.core.internal.resources;

import java.net.URI;
import java.net.URISyntaxException;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.runtime.*;

Object for describing the characteristics of linked resources that are stored
in the project description.
/**
 * Object for describing the characteristics of linked resources that are stored
 * in the project description.
 */
public class LinkDescription implements Comparable<LinkDescription> {
	public static final URI VIRTUAL_LOCATION = getVirtualLocation();

	private static URI getVirtualLocation() {
		try {
			return new URI("virtual:/virtual"); //$NON-NLS-1$
		} catch (URISyntaxException e) {
			//cannot happen
			return null;
		}
	}

	private URI localLocation;

	
The project relative path.
/**
	 * The project relative path.
	 */
	private IPath path;
	
The resource type (IResource.FILE or IResoruce.FOLDER)
/**
	 * The resource type (IResource.FILE or IResoruce.FOLDER)
	 */
	private int type;

	public LinkDescription() {
		this.path = Path.EMPTY;
		this.type = -1;
	}

	public LinkDescription(IResource linkedResource, URI location) {
		super();
		Assert.isNotNull(linkedResource);
		Assert.isNotNull(location);
		this.type = linkedResource.getType();
		this.path = linkedResource.getProjectRelativePath();
		this.localLocation = location;
	}

	@Override
	public boolean equals(Object o) {
		if (o == null) {
			return false;
		}
		if (o.getClass() != this.getClass())
			return false;
		LinkDescription other = (LinkDescription) o;
		return localLocation.equals(other.localLocation) && path.equals(other.path) && type == other.type;
	}

	public URI getLocationURI() {
		return localLocation;
	}

	
Returns the project relative path of the resource that is linked.
Returns:
the project relative path of the resource that is linked./**
	 * Returns the project relative path of the resource that is linked.
	 * @return the project relative path of the resource that is linked.
	 */
	public IPath getProjectRelativePath() {
		return path;
	}

	public int getType() {
		return type;
	}

	public boolean isGroup() {
		return localLocation.equals(VIRTUAL_LOCATION);
	}

	@Override
	public int hashCode() {
		return type + path.hashCode() + localLocation.hashCode();
	}

	public void setLocationURI(URI location) {
		this.localLocation = location;
	}

	public void setPath(IPath path) {
		this.path = path;
	}

	public void setType(int type) {
		this.type = type;
	}

	
Compare link descriptions in a way that sorts them topologically by path. This is important to ensure we process links in topological (breadth-first) order when reconciling links. See Project.reconcileLinksAndGroups(ProjectDescription). /**
	 * Compare link descriptions in a way that sorts them topologically by path.
	 * This is important to ensure we process links in topological (breadth-first) order when reconciling
	 * links.  See {@link Project#reconcileLinksAndGroups(ProjectDescription)}.
	 */
	@Override
	public int compareTo(LinkDescription that) {
		IPath path1 = this.getProjectRelativePath();
		IPath path2 = that.getProjectRelativePath();
		int count1 = path1.segmentCount();
		int compare = count1 - path2.segmentCount();
		if (compare != 0)
			return compare;
		for (int i = 0; i < count1; i++) {
			compare = path1.segment(i).compareTo(path2.segment(i));
			if (compare != 0)
				return compare;
		}
		return 0;
	}
}