FilterDefinition.java

/**
 * 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.
 */
package org.apache.camel.model;

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlRootElement;

import org.apache.camel.Predicate;
import org.apache.camel.Processor;
import org.apache.camel.model.language.ExpressionDefinition;
import org.apache.camel.processor.FilterProcessor;
import org.apache.camel.spi.AsPredicate;
import org.apache.camel.spi.Metadata;
import org.apache.camel.spi.RouteContext;

/**
 * Filter out messages based using a predicate
 *
 * @version 
 */
@Metadata(label = "eip,routing") @AsPredicate
@XmlRootElement(name = "filter")
@XmlAccessorType(XmlAccessType.FIELD)
public class FilterDefinition extends ExpressionNode {

    public FilterDefinition() {
    }

    public FilterDefinition(ExpressionDefinition expression) {
        super(expression);
    }

    public FilterDefinition(Predicate predicate) {
        super(predicate);
    }

    @Override
    public String toString() {
        return "Filter[" + getExpression() + " -> " + getOutputs() + "]";
    }
    
    @Override
    public String getLabel() {
        return "filter[" + getExpression() + "]";
    }
    
    @Override
    public FilterProcessor createProcessor(RouteContext routeContext) throws Exception {
        return createFilterProcessor(routeContext);
    }
    
    @Override
    protected FilterProcessor createFilterProcessor(RouteContext routeContext) throws Exception {
        // filter EIP should have child outputs
        Processor childProcessor = this.createChildProcessor(routeContext, true);
        return new FilterProcessor(createPredicate(routeContext), childProcessor);
    }

    /**
     * Expression to determine if the message should be filtered or not. If the expression returns an empty value or <tt>false</tt>
     * then the message is filtered (dropped), otherwise the message is continued being routed.
     */
    @Override
    public void setExpression(ExpressionDefinition expression) {
        // override to include javadoc what the expression is used for
        super.setExpression(expression);
    }
}