001    /**
002     *
003     * Licensed to the Apache Software Foundation (ASF) under one or more
004     * contributor license agreements.  See the NOTICE file distributed with
005     * this work for additional information regarding copyright ownership.
006     * The ASF licenses this file to You under the Apache License, Version 2.0
007     * (the "License"); you may not use this file except in compliance with
008     * the License.  You may obtain a copy of the License at
009     *
010     * http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    package org.apache.camel.impl;
019    
020    import org.apache.camel.Predicate;
021    import org.apache.camel.Exchange;
022    import org.apache.camel.Expression;
023    import org.apache.camel.util.ObjectHelper;
024    import static org.apache.camel.util.ObjectHelper.notNull;
025    
026    /**
027     * A useful base class for {@link Predicate} implementations
028     *
029     * @version $Revision: 1.1 $
030     */
031    public abstract class BinaryPredicateSupport<E extends Exchange> implements Predicate<E> {
032    
033        private final Expression<E> left;
034        private final Expression<E> right;
035    
036        protected BinaryPredicateSupport(Expression<E> left, Expression<E> right) {
037            notNull(left, "left");
038            notNull(right, "right");
039    
040            this.left = left;
041            this.right = right;
042        }
043    
044        @Override
045        public String toString() {
046            return left + " " + getOperationText() + " " + right;
047        }
048    
049        public boolean matches(E exchange) {
050            Object leftValue = left.evaluate(exchange);
051            Object rightValue = right.evaluate(exchange);
052            return matches(exchange, leftValue, rightValue);
053        }
054    
055        public void assertMatches(String text, E exchange) {
056            Object leftValue = left.evaluate(exchange);
057            Object rightValue = right.evaluate(exchange);
058            if (!matches(exchange, leftValue, rightValue)) {
059                throw new AssertionError(assertionFailureMessage(exchange, leftValue, rightValue));
060            }
061        }
062    
063        protected abstract boolean matches(E exchange, Object leftValue, Object rightValue);
064    
065        protected abstract String getOperationText();
066    
067        protected String assertionFailureMessage(E exchange, Object leftValue, Object rightValue) {
068            return this + " failed on " + exchange + " with left value <" + leftValue + "> right value <" + rightValue + ">";
069        }
070    }