001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.camel.util;
018
019import org.apache.camel.CamelContext;
020import org.apache.camel.CamelContextAware;
021import org.apache.camel.Exchange;
022import org.apache.camel.Expression;
023import org.apache.camel.Predicate;
024
025/**
026 * To adapt {@link org.apache.camel.Expression} as a {@link Predicate}
027 */
028public final class ExpressionToPredicateAdapter implements Predicate, CamelContextAware {
029    private final Expression expression;
030
031    public ExpressionToPredicateAdapter(Expression expression) {
032        this.expression = expression;
033    }
034
035    public boolean matches(Exchange exchange) {
036        if (expression instanceof Predicate) {
037            return ((Predicate) expression).matches(exchange);
038        } else {
039            Object value = expression.evaluate(exchange, Object.class);
040            return ObjectHelper.evaluateValuePredicate(value);
041        }
042    }
043
044    @Override
045    public String toString() {
046        return expression.toString();
047    }
048
049    /**
050     * Converts the given expression into an {@link Predicate}
051     */
052    public static Predicate toPredicate(final Expression expression) {
053        return new ExpressionToPredicateAdapter(expression);
054    }
055
056    @Override
057    public void setCamelContext(CamelContext camelContext) {
058        if (expression instanceof CamelContextAware) {
059            ((CamelContextAware) expression).setCamelContext(camelContext);
060        }
061    }
062
063    @Override
064    public CamelContext getCamelContext() {
065        if (expression instanceof CamelContextAware) {
066            return ((CamelContextAware) expression).getCamelContext();
067        } else {
068            return null;
069        }
070    }
071}