/*******************************************************************************
 * Copyright (c) 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 ******************************************************************************/

package org.eclipse.ui.examples.contributions.model;

import java.util.HashMap;
import java.util.Map;

import org.eclipse.ui.AbstractSourceProvider;
import org.eclipse.ui.ISources;

/**
 * An example of provide a Person as a variable to the evaluation service.
 * 
 * @since 3.4
 */
public class UserSourceProvider extends AbstractSourceProvider {
	public static final String USER = "org.eclipse.ui.examples.contributions.user"; //$NON-NLS-1$
	private static final String[] PROVIDED_SOURCE_NAMES = new String[] { USER };
	private static final Object GUEST = new Object();

	private Person user = null;

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.ui.ISourceProvider#dispose()
	 */
	public void dispose() {
		user = null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.ui.ISourceProvider#getCurrentState()
	 */
	public Map getCurrentState() {
		Map m = new HashMap();
		m.put(USER, getCurrentUser());
		return m;
	}

	private Object getCurrentUser() {
		return user == null ? GUEST : user;
	}

	public void login(Person person) {
		user = person;
		// I'm not sure whether this has to be accurate, so use the matching
		// declaration priority <<1 for now
		fireSourceChanged(ISources.ACTIVE_SITE << 1, USER, getCurrentUser());
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.ui.ISourceProvider#getProvidedSourceNames()
	 */
	public String[] getProvidedSourceNames() {
		return PROVIDED_SOURCE_NAMES;
	}
}