Copyright (c) 2000, 2008 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, 2008 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.core.internal.expressions;

import java.util.ArrayList;
import java.util.Arrays;
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;

public abstract class CompositeExpression extends Expression {

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

	
The seed for the hash code for all composite expressions.
/**
	 * The seed for the hash code for all composite expressions.
	 */
	private static final int HASH_INITIAL= CompositeExpression.class.getName().hashCode();

	protected List<Expression> 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 fExpressions.toArray(new Expression[fExpressions.size()]);
	}

	protected EvaluationResult evaluateAnd(IEvaluationContext scope) throws CoreException {
		if (fExpressions == null)
			return EvaluationResult.TRUE;
		EvaluationResult result= EvaluationResult.TRUE;
		for (Expression expression : fExpressions) {
			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 (Expression expression : fExpressions) {
			result= result.or(expression.evaluate(scope));
			if (result == EvaluationResult.TRUE)
				return result;
		}
		return result;
	}

	@Override
	public void collectExpressionInfo(ExpressionInfo info) {
		if (fExpressions == null)
			return;
		for (Expression expression : fExpressions) {
			expression.collectExpressionInfo(info);
		}
	}

	@Override
	protected int computeHashCode() {
		return HASH_INITIAL * HASH_FACTOR + hashCode(fExpressions);
	}

	@Override
	public String toString() {
		StringBuilder builder = new StringBuilder(getClass().getSimpleName());
		Expression[] children = getChildren();
		if (children.length > 0) {
			builder.append(" [children="); //$NON-NLS-1$
			builder.append(Arrays.toString(children));
			builder.append("]"); //$NON-NLS-1$
		}
		return builder.toString();
	}

}