bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/expressions/CompositeExpression.java

/*******************************************************************************
 * Copyright (c) 2006, 2007 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.expressions;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.eclipse.core.expressions.EvaluationResult;
import org.eclipse.core.expressions.Expression;
import org.eclipse.core.expressions.ExpressionInfo;
import org.eclipse.core.expressions.IEvaluationContext;
import org.eclipse.core.runtime.CoreException;

/**
 * Copied from org.eclipse.core.internal.expressions.
 */
public abstract class CompositeExpression extends Expression {

	private static final Expression[] EMPTY_ARRAY = new Expression[0];

	protected List fExpressions;

	public void add(Expression expression) {
		if (fExpressions == null) {
			fExpressions = new ArrayList(2);
		}
		fExpressions.add(expression);
	}

	public Expression[] getChildren() {
		if (fExpressions == null) {
			return EMPTY_ARRAY;
		}
		return (Expression[]) fExpressions.toArray(new Expression[fExpressions
				.size()]);
	}

	protected EvaluationResult evaluateAnd(IEvaluationContext scope)
			throws CoreException {
		if (fExpressions == null) {
			return EvaluationResult.TRUE;
		}
		EvaluationResult result = EvaluationResult.TRUE;
		for (Iterator iter = fExpressions.iterator(); iter.hasNext();) {
			Expression expression = (Expression) iter.next();
			result = result.and(expression.evaluate(scope));
			// 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;
	}

	protected EvaluationResult evaluateOr(IEvaluationContext scope)
			throws CoreException {
		if (fExpressions == null) {
			return EvaluationResult.TRUE;
		}
		EvaluationResult result = EvaluationResult.FALSE;
		for (Iterator iter = fExpressions.iterator(); iter.hasNext();) {
			Expression expression = (Expression) iter.next();
			result = result.or(expression.evaluate(scope));
			if (result == EvaluationResult.TRUE) {
				return result;
			}
		}
		return result;
	}

	public void collectExpressionInfo(ExpressionInfo info) {
		if (fExpressions == null) {
			return;
		}
		for (Iterator iter = fExpressions.iterator(); iter.hasNext();) {
			Expression expression = (Expression) iter.next();
			expression.collectExpressionInfo(info);
		}
	}
}