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.spring;
018
019import org.apache.camel.CamelContext;
020import org.apache.camel.builder.RouteBuilder;
021import org.apache.camel.spring.spi.SpringTransactionPolicy;
022import org.apache.camel.spring.spi.TransactionErrorHandlerBuilder;
023import org.springframework.context.ApplicationContext;
024import org.springframework.context.ApplicationContextAware;
025import org.springframework.transaction.PlatformTransactionManager;
026import org.springframework.transaction.support.TransactionTemplate;
027
028/**
029 * An extension of the {@link RouteBuilder} to provide some additional helper
030 * methods
031 *
032 * @version 
033 */
034public abstract class SpringRouteBuilder extends RouteBuilder implements ApplicationContextAware {
035    private ApplicationContext applicationContext;
036
037    /**
038     * Looks up the bean with the given name in the application context and
039     * returns it, or throws an exception if the bean is not present or is not
040     * of the given type
041     *
042     * @param beanName the name of the bean in the application context
043     * @param type the type of the bean
044     * @return the bean
045     */
046    public <T> T lookup(String beanName, Class<T> type) {
047        ApplicationContext context = getApplicationContext();
048        return context.getBean(beanName, type);
049    }
050
051    /**
052     * Looks up the bean with the given type in the application context and
053     * returns it, or throws an exception if the bean is not present or there
054     * are multiple possible beans to choose from for the given type
055     *
056     * @param type the type of the bean
057     * @return the bean
058     */
059    public <T> T lookup(Class<T> type) {
060        ApplicationContext context = getApplicationContext();
061        String[] names = context.getBeanNamesForType(type, true, true);
062        if (names != null) {
063            int count = names.length;
064            if (count == 1) {
065                // lets instantiate the single bean
066                return context.getBean(names[0], type);
067            } else if (count > 1) {
068                throw new IllegalArgumentException("Too many beans in the application context of type: " + type + ". Found: " + count);
069            }
070        }
071        throw new IllegalArgumentException("No bean available in the application context of type: " + type);
072    }
073
074    /**
075     * Returns the application context which has been configured via the
076     * {@link #setApplicationContext(ApplicationContext)} method or from the
077     * underlying {@link SpringCamelContext}
078     */
079    public ApplicationContext getApplicationContext() {
080        if (applicationContext == null) {
081            CamelContext camelContext = getContext();
082            if (camelContext instanceof SpringCamelContext) {
083                SpringCamelContext springCamelContext = (SpringCamelContext)camelContext;
084                return springCamelContext.getApplicationContext();
085            } else {
086                throw new IllegalArgumentException("This SpringBuilder is not being used with a SpringCamelContext and there is no applicationContext property configured");
087            }
088        }
089        return applicationContext;
090    }
091
092    /**
093     * Sets the application context to use to lookup beans
094     */
095    public void setApplicationContext(ApplicationContext applicationContext) {        
096        this.applicationContext = applicationContext;
097    }
098
099    /**
100     * Creates a transaction error handler that will lookup in application context for
101     * an exiting transaction manager.
102     *
103     * @return the created error handler
104     */
105    public TransactionErrorHandlerBuilder transactionErrorHandler() {
106        return new TransactionErrorHandlerBuilder();
107    }
108
109    /**
110     * Creates a transaction error handler.
111     *
112     * @param policy   using this transaction policy (eg: required, supports, ...)
113     * @return the created error handler
114     */
115    public TransactionErrorHandlerBuilder transactionErrorHandler(SpringTransactionPolicy policy) {
116        return transactionErrorHandler(policy.getTransactionTemplate());
117    }
118
119    /**
120     * Creates a transaction error handler.
121     *
122     * @param template the spring transaction template
123     * @return the created error handler
124     */
125    public TransactionErrorHandlerBuilder transactionErrorHandler(TransactionTemplate template) {
126        TransactionErrorHandlerBuilder answer = new TransactionErrorHandlerBuilder();
127        answer.setTransactionTemplate(template);
128        return answer;
129    }
130
131    /**
132     * Creates a transaction error handler.
133     *
134     * @param transactionManager the spring transaction manager
135     * @return the created error handler
136     */
137    public TransactionErrorHandlerBuilder transactionErrorHandler(PlatformTransactionManager transactionManager) {
138        TransactionTemplate template = new TransactionTemplate(transactionManager);
139        return transactionErrorHandler(template);
140    }
141
142}