EDIT

/*******************************************************************************

 * Copyright (c) 2005, 2010 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.internal.navigator;

import java.util.ArrayList;

import java.util.Iterator;

import java.util.List;

import org.eclipse.core.expressions.ElementHandler;

import org.eclipse.core.expressions.EvaluationResult;

import org.eclipse.core.expressions.Expression;

import org.eclipse.core.expressions.ExpressionConverter;

import org.eclipse.core.expressions.IEvaluationContext;

import org.eclipse.core.runtime.Assert;

import org.eclipse.core.runtime.IConfigurationElement;

import org.eclipse.core.runtime.SafeRunner;

/**

 * Create an AND-type core expression from an IConfigurationElement of arbitrary

 * name.

 * 

 */

public class CustomAndExpression extends Expression {

	protected List fExpressions;

	/**

	 * Create an AND-type core expression from an IConfigurationElement of

	 * arbitrary name. The children elements are combined using boolean AND

	 * semantics to evaluate the expression.

	 * 

	 * @param element

	 *            An IConfigurationElement of arbitrary name.

	 */

	public CustomAndExpression(IConfigurationElement element) {

		Assert.isNotNull(element);

		final IConfigurationElement[] children = element.getChildren();

		if (children.length == 0)

			return;

		SafeRunner.run(new NavigatorSafeRunnable() {

			public void run() throws Exception {

				fExpressions = new ArrayList();

				for (int i = 0; i < children.length; i++) {

					fExpressions.add(ElementHandler.getDefault().create(

							ExpressionConverter.getDefault(), children[i]));

				}

			}

		});

	}

	public EvaluationResult evaluate(IEvaluationContext scope) {

		if (fExpressions == null) {

			return EvaluationResult.TRUE;

		}

		NavigatorPlugin.Evaluator evaluator = new NavigatorPlugin.Evaluator();

		EvaluationResult result = EvaluationResult.TRUE;

		for (Iterator iter = fExpressions.iterator(); iter.hasNext();) {

			Expression expression = (Expression) iter.next();

			evaluator.expression = expression;

			evaluator.scope = scope;

			SafeRunner.run(evaluator);

			result = result.and(evaluator.result);

			// keep iterating even if we have a not loaded found. It can be

			// that we find a false which will result in a better result.

			if (result == EvaluationResult.FALSE) {

				return result;

			}

		}

		return result;

	}

}