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     */
017    package org.apache.camel.spring;
018    
019    import org.apache.camel.CamelContext;
020    import org.apache.camel.builder.RouteBuilder;
021    import org.apache.camel.spring.spi.SpringTransactionPolicy;
022    import org.apache.camel.spring.spi.TransactionErrorHandlerBuilder;
023    import org.springframework.context.ApplicationContext;
024    import org.springframework.context.ApplicationContextAware;
025    import org.springframework.transaction.PlatformTransactionManager;
026    import org.springframework.transaction.support.TransactionTemplate;
027    
028    /**
029     * An extension of the {@link RouteBuilder} to provide some additional helper
030     * methods
031     *
032     * @version $Revision: 15191 $
033     */
034    public 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        @SuppressWarnings("unchecked")
047        public <T> T lookup(String beanName, Class<T> type) {
048            ApplicationContext context = getApplicationContext();
049            return (T)context.getBean(beanName, type);
050        }
051    
052        /**
053         * Looks up the bean with the given type in the application context and
054         * returns it, or throws an exception if the bean is not present or there
055         * are multiple possible beans to choose from for the given type
056         *
057         * @param type the type of the bean
058         * @return the bean
059         */
060        @SuppressWarnings("unchecked")
061        public <T> T lookup(Class<T> type) {
062            ApplicationContext context = getApplicationContext();
063            String[] names = context.getBeanNamesForType(type, true, true);
064            if (names != null) {
065                int count = names.length;
066                if (count == 1) {
067                    // lets instantiate the single bean
068                    return (T)context.getBean(names[0]);
069                } else if (count > 1) {
070                    throw new IllegalArgumentException("Too many beans in the application context of type: " + type + ". Found: " + count);
071                }
072            }
073            throw new IllegalArgumentException("No bean available in the application context of type: " + type);
074        }
075    
076        /**
077         * Returns the application context which has been configured via the
078         * {@link #setApplicationContext(ApplicationContext)} method or from the
079         * underlying {@link SpringCamelContext}
080         */
081        public ApplicationContext getApplicationContext() {
082            if (applicationContext == null) {
083                CamelContext camelContext = getContext();
084                if (camelContext instanceof SpringCamelContext) {
085                    SpringCamelContext springCamelContext = (SpringCamelContext)camelContext;
086                    return springCamelContext.getApplicationContext();
087                } else {
088                    throw new IllegalArgumentException("This SpringBuilder is not being used with a SpringCamelContext and there is no applicationContext property configured");
089                }
090            }
091            return applicationContext;
092        }
093    
094        /**
095         * Sets the application context to use to lookup beans
096         */
097        public void setApplicationContext(ApplicationContext applicationContext) {        
098            this.applicationContext = applicationContext;
099        }
100    
101        /**
102         * Creates a transaction error handler that will lookup in application context for
103         * an exiting transaction manager.
104         *
105         * @return the created error handler
106         */
107        public TransactionErrorHandlerBuilder transactionErrorHandler() {
108            return new TransactionErrorHandlerBuilder();
109        }
110    
111        /**
112         * Creates a transaction error handler.
113         *
114         * @param policy   using this transaction policy (eg: required, supports, ...)
115         * @return the created error handler
116         */
117        public TransactionErrorHandlerBuilder transactionErrorHandler(SpringTransactionPolicy policy) {
118            return transactionErrorHandler(policy.getTransactionTemplate());
119        }
120    
121        /**
122         * Creates a transaction error handler.
123         *
124         * @param template the spring transaction template
125         * @return the created error handler
126         */
127        public TransactionErrorHandlerBuilder transactionErrorHandler(TransactionTemplate template) {
128            TransactionErrorHandlerBuilder answer = new TransactionErrorHandlerBuilder();
129            answer.setTransactionTemplate(template);
130            return answer;
131        }
132    
133        /**
134         * Creates a transaction error handler.
135         *
136         * @param transactionManager the spring transaction manager
137         * @return the created error handler
138         */
139        public TransactionErrorHandlerBuilder transactionErrorHandler(PlatformTransactionManager transactionManager) {
140            TransactionTemplate template = new TransactionTemplate(transactionManager);
141            return transactionErrorHandler(template);
142        }
143    
144    }