Copyright (c) 2000, 2014 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) 2000, 2014 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.resources;

import java.io.IOException;
import java.net.*;
import org.eclipse.core.internal.boot.PlatformURLConnection;
import org.eclipse.core.internal.boot.PlatformURLHandler;
import org.eclipse.core.internal.utils.Messages;
import org.eclipse.core.resources.*;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;
import org.eclipse.osgi.util.NLS;

Platform URL support platform:/resource/<path>/<resource> maps to resource in current workspace /**
 * Platform URL support {@literal platform:/resource/<path>/<resource>} maps to
 * resource in current workspace
 */
public class PlatformURLResourceConnection extends PlatformURLConnection {

	// resource/ protocol
	public static final String RESOURCE = "resource"; //$NON-NLS-1$
	public static final String RESOURCE_URL_STRING = PlatformURLHandler.PROTOCOL + PlatformURLHandler.PROTOCOL_SEPARATOR + '/' + RESOURCE + '/';
	private static URL rootURL;

	public PlatformURLResourceConnection(URL url) {
		super(url);
	}

	@Override
	protected boolean allowCaching() {
		return false; // don't cache, workspace is local
	}

	@Override
	protected URL resolve() throws IOException {
		String filePath = url.getFile().trim();
		filePath = URLDecoder.decode(filePath, "UTF-8"); //$NON-NLS-1$
		IPath spec = new Path(filePath).makeRelative();
		if (!spec.segment(0).equals(RESOURCE))
			throw new IOException(NLS.bind(Messages.url_badVariant, url));
		int count = spec.segmentCount();
		// if there is only one segment then we are talking about the workspace root.
		if (count == 1)
			return rootURL;
		// if there are two segments then the second is a project name.
		IProject project = ResourcesPlugin.getWorkspace().getRoot().getProject(spec.segment(1));
		if (!project.exists()) {
			String message = NLS.bind(Messages.url_couldNotResolve_projectDoesNotExist, project.getName(), url.toExternalForm());
			throw new IOException(message);
		}

		IResource resource = null;
		IPath result = null;

		if (count == 2) {
			resource = project;
		} else {
			spec = spec.removeFirstSegments(2);
			resource = project.getFile(spec);
		}

		result = resource.getLocation();

		if (result == null) {
			URI uri = resource.getLocationURI();
			if (uri != null) {
				try {
					URL url2 = uri.toURL();
					if (url2.getProtocol().equals("file")) //$NON-NLS-1$
						return url2;
				} catch (MalformedURLException e) {
					String message = NLS.bind(Messages.url_couldNotResolve_URLProtocolHandlerCanNotResolveURL, uri.toString(), url.toExternalForm());
					throw new IOException(message);
				}
			}
			String message = NLS.bind(Messages.url_couldNotResolve_resourceLocationCanNotBeDetermined, resource.getFullPath(), url.toExternalForm());
			throw new IOException(message);
		}
		return new URL("file", "", result.toString()); //$NON-NLS-1$ //$NON-NLS-2$
	}

	
This method is called during resource plugin startup() initialization.
Params:
root – URL to the root of the current workspace./**
	 * This method is called during resource plugin startup() initialization.
	 *
	 * @param root URL to the root of the current workspace.
	 */
	public static void startup(IPath root) {
		// register connection type for platform:/resource/ handling
		if (rootURL != null)
			return;
		try {
			rootURL = root.toFile().toURL();
		} catch (MalformedURLException e) {
			// should never happen but if it does, the resource URL cannot be supported.
			return;
		}
		PlatformURLHandler.register(RESOURCE, PlatformURLResourceConnection.class);
	}
}