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.io.IOException; 020 021import org.apache.camel.CamelContext; 022import org.apache.camel.spi.FactoryFinder; 023import org.apache.camel.spi.HeadersMapFactory; 024import org.slf4j.Logger; 025import org.slf4j.LoggerFactory; 026 027/** 028 * Factory to create the {@link HeadersMapFactory} implementation to be used. 029 * 030 * @see HeadersMapFactory 031 */ 032public class HeadersMapFactoryResolver { 033 034 public static final String RESOURCE_PATH = "META-INF/services/org/apache/camel/"; 035 036 private static final Logger LOG = LoggerFactory.getLogger(HeadersMapFactoryResolver.class); 037 038 private FactoryFinder factoryFinder; 039 040 public HeadersMapFactory resolve(CamelContext context) { 041 // use factory finder to find a custom implementations 042 Class<?> type = null; 043 try { 044 type = findFactory("headers-map-factory", context); 045 } catch (Exception e) { 046 // ignore 047 } 048 049 if (type != null) { 050 if (LOG.isDebugEnabled()) { 051 LOG.debug("Found HeadersMapFactory: {} via: {}{}", type.getName(), factoryFinder.getResourcePath(), "headers-map-factory"); 052 } 053 if (HeadersMapFactory.class.isAssignableFrom(type)) { 054 HeadersMapFactory answer = (HeadersMapFactory) context.getInjector().newInstance(type); 055 LOG.info("Detected and using custom HeadersMapFactory: {}", answer); 056 return answer; 057 } else { 058 throw new IllegalArgumentException("Type is not a HeadersMapFactory implementation. Found: " + type.getName()); 059 } 060 } 061 062 // fallback to default 063 LOG.debug("Creating default HeadersMapFactory"); 064 return new DefaultHeadersMapFactory(); 065 } 066 067 private Class<?> findFactory(String name, CamelContext context) throws ClassNotFoundException, IOException { 068 if (factoryFinder == null) { 069 factoryFinder = context.getFactoryFinder(RESOURCE_PATH); 070 } 071 return factoryFinder.findClass(name); 072 } 073 074} 075