Copyright (c) 2000, 2011 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, 2011 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.debug.internal.core.sourcelookup;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.debug.core.DebugPlugin;
import org.eclipse.debug.core.ILaunchConfiguration;
import org.eclipse.debug.core.sourcelookup.ISourceContainer;
import org.eclipse.debug.core.sourcelookup.ISourcePathComputer;
import org.eclipse.debug.core.sourcelookup.ISourcePathComputerDelegate;
import org.eclipse.debug.internal.core.IConfigurationElementConstants;

Proxy to contributed source path computer extension.
See Also:
IConfigurationElementConstants/**
 * Proxy to contributed source path computer extension.
 *
 * @see IConfigurationElementConstants
 */
public class SourcePathComputer implements ISourcePathComputer {

	// lazily instantiated delegate
	private ISourcePathComputerDelegate fDelegate = null;

	// extension definition
	private IConfigurationElement fElement = null;

	
Constructs a source path computer on the given extension.
Params:
element – extension definition/**
	 * Constructs a source path computer on the given extension.
	 *
	 * @param element extension definition
	 */
	public SourcePathComputer(IConfigurationElement element) {
		fElement = element;
	}

	@Override
	public String getId() {
		return fElement.getAttribute(IConfigurationElementConstants.ID);
	}

	
Lazily instantiates and returns the underlying source container type.
Throws:
CoreException – if unable to instantiate
Returns:
the ISourcePathComputerDelegate/**
	 * Lazily instantiates and returns the underlying source container type.
	 * @return the {@link ISourcePathComputerDelegate}
	 * @exception CoreException if unable to instantiate
	 */
	private ISourcePathComputerDelegate getDelegate() throws CoreException {
		if (fDelegate == null) {
			fDelegate = (ISourcePathComputerDelegate) fElement.createExecutableExtension(IConfigurationElementConstants.CLASS);
		}
		return fDelegate;
	}

	@Override
	public ISourceContainer[] computeSourceContainers(ILaunchConfiguration configuration, IProgressMonitor monitor) {
		try {
			return getDelegate().computeSourceContainers(configuration, monitor);
		} catch (CoreException e) {
			DebugPlugin.log(e);
		}
		return new ISourceContainer[0];
	}
}