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.impl; 018 019import java.lang.reflect.Method; 020import java.util.Collections; 021import java.util.HashMap; 022import java.util.Map; 023 024import org.apache.camel.Endpoint; 025import org.apache.camel.Exchange; 026import org.apache.camel.InvokeOnHeader; 027import org.apache.camel.InvokeOnHeaders; 028import org.apache.camel.Message; 029import org.apache.camel.NoSuchHeaderException; 030import org.apache.camel.Processor; 031import org.slf4j.Logger; 032import org.slf4j.LoggerFactory; 033 034/** 035 * A selector-based produced which uses an header value to determine which processor 036 * should be invoked. 037 */ 038public class HeaderSelectorProducer extends BaseSelectorProducer { 039 private static final Logger LOGGER = LoggerFactory.getLogger(HeaderSelectorProducer.class); 040 041 private final String header; 042 private final String defaultHeaderValue; 043 private final Object target; 044 private Map<String, Processor> handlers; 045 046 public HeaderSelectorProducer(Endpoint endpoint, String header) { 047 this(endpoint, header, null, null); 048 } 049 050 public HeaderSelectorProducer(Endpoint endpoint, String header, Object target) { 051 this(endpoint, header, null, target); 052 } 053 054 public HeaderSelectorProducer(Endpoint endpoint, String header, String defaultHeaderValue) { 055 this(endpoint, header, defaultHeaderValue, null); 056 } 057 058 public HeaderSelectorProducer(Endpoint endpoint, String header, String defaultHeaderValue, Object target) { 059 super(endpoint); 060 061 this.header = header; 062 this.defaultHeaderValue = defaultHeaderValue; 063 this.target = target != null ? target : this; 064 this.handlers = new HashMap<>(); 065 } 066 067 @Override 068 protected void doStart() throws Exception { 069 for (final Method method : target.getClass().getDeclaredMethods()) { 070 InvokeOnHeaders annotation = method.getAnnotation(InvokeOnHeaders.class); 071 if (annotation != null) { 072 for (InvokeOnHeader processor : annotation.value()) { 073 bind(processor, method); 074 } 075 } else { 076 bind(method.getAnnotation(InvokeOnHeader.class), method); 077 } 078 } 079 080 handlers = Collections.unmodifiableMap(handlers); 081 082 super.doStart(); 083 } 084 085 @Override 086 protected Processor getProcessor(Exchange exchange) throws Exception { 087 final String action = exchange.getIn().getHeader(header, defaultHeaderValue, String.class); 088 if (action == null) { 089 throw new NoSuchHeaderException(exchange, header, String.class); 090 } 091 092 return handlers.get(action); 093 } 094 095 protected void onMissingProcessor(Exchange exchange) throws Exception { 096 throw new IllegalStateException( 097 "Unsupported operation " + exchange.getIn().getHeader(header) 098 ); 099 } 100 101 protected final void bind(String key, Processor processor) { 102 if (handlers.containsKey(key)) { 103 LOGGER.warn("A processor is already set for action {}", key); 104 } 105 106 this.handlers.put(key, processor); 107 } 108 109 private void bind(InvokeOnHeader handler, final Method method) { 110 if (handler != null && method.getParameterCount() == 1) { 111 method.setAccessible(true); 112 113 final Class<?> type = method.getParameterTypes()[0]; 114 115 LOGGER.debug("bind key={}, class={}, method={}, type={}", 116 handler.value(), this.getClass(), method.getName(), type); 117 118 if (Message.class.isAssignableFrom(type)) { 119 bind(handler.value(), e -> method.invoke(target, e.getIn())); 120 } else { 121 bind(handler.value(), e -> method.invoke(target, e)); 122 } 123 } 124 } 125}