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.model;
018
019import javax.xml.bind.annotation.XmlRootElement;
020
021import org.apache.camel.Predicate;
022import org.apache.camel.model.language.ExpressionDefinition;
023import org.apache.camel.processor.FilterProcessor;
024import org.apache.camel.spi.Metadata;
025import org.apache.camel.spi.RouteContext;
026
027/**
028 * Triggers a route when an expression evaluates to <tt>true</tt>
029 * 
030 * @version 
031 */
032@Metadata(label = "eip,routing")
033@XmlRootElement(name = "when")
034public class WhenDefinition extends ExpressionNode {
035
036    public WhenDefinition() {
037    }
038
039    public WhenDefinition(Predicate predicate) {
040        super(predicate);
041    }
042
043    public WhenDefinition(ExpressionDefinition expression) {
044        super(expression);
045    }
046
047    @Override
048    public String toString() {
049        return "When[" + description() + " -> " + getOutputs() + "]";
050    }
051
052    protected String description() {
053        StringBuilder sb = new StringBuilder();
054        if (getExpression() != null) {
055            String language = getExpression().getLanguage();
056            if (language != null) {
057                sb.append(language).append("{");
058            }
059            sb.append(getExpression().getLabel());
060            if (language != null) {
061                sb.append("}");
062            }
063        }
064        return sb.toString();
065    }
066
067    @Override
068    public String getLabel() {
069        return "when[" + description() + "]";
070    }
071
072    @Override
073    public FilterProcessor createProcessor(RouteContext routeContext) throws Exception {
074        return createFilterProcessor(routeContext);
075    }
076
077    /**
078     * Expression used as the predicate to evaluate whether this when should trigger and route the message or not.
079     */
080    @Override
081    public void setExpression(ExpressionDefinition expression) {
082        // override to include javadoc what the expression is used for
083        super.setExpression(expression);
084    }
085
086    @Override
087    public ProcessorDefinition<?> endParent() {
088        // when using when in the DSL we don't want to end back to this when, but instead
089        // the parent of this, so return the parent
090        return this.getParent();
091    }
092}