Copyright (c) 2005, 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) 2005, 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.jdt.internal.launching;

import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.Path;
import org.eclipse.debug.core.ILaunchConfiguration;
import org.eclipse.debug.core.ILaunchConfigurationMigrationDelegate;
import org.eclipse.debug.core.ILaunchConfigurationWorkingCopy;
import org.eclipse.jdt.core.IJavaProject;
import org.eclipse.jdt.core.IType;
import org.eclipse.jdt.core.JavaCore;
import org.eclipse.jdt.core.JavaModelException;
import org.eclipse.jdt.launching.IJavaLaunchConfigurationConstants;

Delegate for migrating Java launch configurations.
The migration process involves a resource mapping being created such that launch configurations
can be filtered from the launch configuration dialog based on resource availability
Since:
3.2/**
 * Delegate for migrating Java launch configurations.
 * The migration process involves a resource mapping being created such that launch configurations
 * can be filtered from the launch configuration dialog based on resource availability
 *
 * @since 3.2
 */
public class JavaMigrationDelegate implements ILaunchConfigurationMigrationDelegate {

	
represents the empty string
/**
	 * represents the empty string
	 */
	protected static final String EMPTY_STRING = ""; //$NON-NLS-1$

	
Constructor needed for reflection
/**
	 * Constructor needed for reflection
	 */
	public JavaMigrationDelegate() {}

	/* (non-Javadoc)
	 * @see org.eclipse.debug.core.ILaunchConfigurationMigrationDelegate#isCandidate()
	 */
	@Override
	public boolean isCandidate(ILaunchConfiguration candidate) throws CoreException {
		String pName = candidate.getAttribute(IJavaLaunchConfigurationConstants.ATTR_PROJECT_NAME, EMPTY_STRING);
		if(pName.equals(EMPTY_STRING)) {
			return false;
		}
		if (!isAvailable(pName)) {
			return false;
		}
		IResource[] mapped = candidate.getMappedResources();
		IResource target = getResource(candidate);
		if (target == null) {
			return mapped != null;
		}
		if (mapped == null) {
			return true;
		}
		if (mapped.length != 1) {
			return true;
		}
		return !target.equals(mapped[0]);
	}

	
Returns whether the given project is available.
Params:
projectName – project name
Returns:
whether the project exists and is open/**
	 * Returns whether the given project is available.
	 *
	 * @param projectName project name
	 * @return whether the project exists and is open
	 */
	private boolean isAvailable(String projectName) {
		IProject project = ResourcesPlugin.getWorkspace().getRoot().getProject(projectName);
		return project.exists() && project.isOpen();
	}

	
Returns the associated IResource for the specified launch configuration
or null if none.
Params:
candidate – the candidate to get the backing resource for
Throws:
CoreException – if there is an error
Returns:
associated IResource or null
Since:
3.3/**
	 * Returns the associated <code>IResource</code> for the specified launch configuration
	 * or <code>null</code> if none.
	 *
	 * @param candidate the candidate to get the backing resource for
	 * @return associated <code>IResource</code> or <code>null</code>
	 *
	 * @since 3.3
	 *
	 * @throws CoreException if there is an error
	 */
	static IResource getResource(ILaunchConfiguration candidate) throws CoreException {
		IResource resource = null;
		String pname = candidate.getAttribute(IJavaLaunchConfigurationConstants.ATTR_PROJECT_NAME, EMPTY_STRING);
		if(Path.ROOT.isValidSegment(pname)) {
			IProject project = ResourcesPlugin.getWorkspace().getRoot().getProject(pname);
			String tname = candidate.getAttribute(IJavaLaunchConfigurationConstants.ATTR_MAIN_TYPE_NAME, EMPTY_STRING);
			if(!EMPTY_STRING.equals(tname)) {
				if(project != null && project.isAccessible()) {
					IJavaProject jproject = JavaCore.create(project);
					if(jproject != null && jproject.exists()) {
						tname = tname.replace('$', '.');
						IType type = jproject.findType(tname);
						if(type != null) {
							try {
								resource = type.getUnderlyingResource();
								if(resource == null) {
									resource = type.getAdapter(IResource.class);
								}
							}
							catch(JavaModelException jme) {
								LaunchingPlugin.log(jme);
								return null;
							}
						}
					}
				}
			} else {
				return project;
			}
			if (resource == null) {
				resource = project;
			}
		}
		return resource;
	}

	/* (non-Javadoc)
	 * @see org.eclipse.debug.core.ILaunchConfigurationMigrationDelegate#migrate(org.eclipse.debug.core.ILaunchConfiguration)
	 */
	@Override
	public void migrate(ILaunchConfiguration candidate) throws CoreException {
		ILaunchConfigurationWorkingCopy wc = candidate.getWorkingCopy();
		updateResourceMapping(wc);
		wc.doSave();
	}

	
Updates the resource mapping for the given launch configuration.
Params:
wc – working copy
Throws:
CoreException – if an exception occurs updating resource mapping./**
	 * Updates the resource mapping for the given launch configuration.
	 *
	 * @param wc working copy
	 * @throws CoreException if an exception occurs updating resource mapping.
	 */
	public static void updateResourceMapping(ILaunchConfigurationWorkingCopy wc) throws CoreException {
		IResource resource = getResource(wc);
		IResource[] resources = null;
		if (resource != null) {
			resources = new IResource[]{resource};
		}
		wc.setMappedResources(resources);
	}

}