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.impl;
018    
019    import java.util.HashMap;
020    import java.util.Map;
021    
022    import org.apache.camel.Message;
023    
024    /**
025     * The default implementation of {@link Message}
026     *
027     * @version $Revision: 640438 $
028     */
029    public class DefaultMessage extends MessageSupport {
030        private Map<String, Object> headers;
031    
032        @Override
033        public String toString() {
034            return "Message: " + getBody();
035        }
036    
037        public Object getHeader(String name) {
038            return getHeaders().get(name);
039        }
040    
041        public <T> T getHeader(String name, Class<T> type) {
042            Object value = getHeader(name);
043            return getExchange().getContext().getTypeConverter().convertTo(type, value);
044        }
045    
046        public void setHeader(String name, Object value) {
047            if (headers == null) {
048                headers = createHeaders();
049            }
050            headers.put(name, value);
051        }
052    
053        public Object removeHeader(String name) {
054            if (headers != null) {
055                return headers.remove(name);
056            } else {
057                return null;
058            }
059        }
060    
061        public Map<String, Object> getHeaders() {
062            if (headers == null) {
063                headers = createHeaders();
064            }
065            return headers;
066        }
067    
068        public void setHeaders(Map<String, Object> headers) {
069            this.headers = headers;
070        }
071    
072        public DefaultMessage newInstance() {
073            return new DefaultMessage();
074        }
075    
076        /**
077         * A factory method to lazily create the headers to make it easy to create
078         * efficient Message implementations which only construct and populate the
079         * Map on demand
080         *
081         * @return return a newly constructed Map possibly containing headers from
082         *         the underlying inbound transport
083         */
084        protected Map<String, Object> createHeaders() {
085            HashMap<String, Object> map = new HashMap<String, Object>();
086            populateInitialHeaders(map);
087            return map;
088        }
089    
090        /**
091         * A strategy method populate the initial set of headers on an inbound
092         * message from an underlying binding
093         *
094         * @param map is the empty header map to populate
095         */
096        protected void populateInitialHeaders(Map<String, Object> map) {
097        }
098    }