/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
using System;

namespace Apache.NMS.Selector
{
    /// <summary>
    /// An expression which performs an operation on one expression value
    /// and returns a boolean value.
    /// </summary>
    public abstract class BooleanUnaryExpression : UnaryExpression, IBooleanExpression
    {
        public BooleanUnaryExpression(IExpression left)
            : base(left)
        {        	
        }

        public bool Matches(MessageEvaluationContext message)
        {
            object value = Evaluate(message);
            return value != null && (bool)value;            
        }
    }
}