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.converter;
018    
019    import java.util.concurrent.Future;
020    
021    import org.apache.camel.Converter;
022    import org.apache.camel.Exchange;
023    import org.apache.camel.StreamCache;
024    import org.apache.camel.TypeConversionException;
025    import org.apache.camel.TypeConverter;
026    import org.apache.camel.support.TypeConverterSupport;
027    import org.apache.camel.util.ExchangeHelper;
028    import org.slf4j.Logger;
029    import org.slf4j.LoggerFactory;
030    
031    /**
032     * Future type converter.
033     *
034     * @version 
035     */
036    @Converter
037    public final class FutureTypeConverter extends TypeConverterSupport {
038    
039        private static final Logger LOG = LoggerFactory.getLogger(FutureTypeConverter.class);
040    
041        private final TypeConverter converter;
042    
043        public FutureTypeConverter(TypeConverter converter) {
044            this.converter = converter;
045        }
046    
047        @Override
048        public <T> T convertTo(Class<T> type, Exchange exchange, Object value) {
049            try {
050                return doConvertTo(type, exchange, value);
051            } catch (Exception e) {
052                throw new TypeConversionException(value, type, e);
053            }
054        }
055    
056        @SuppressWarnings("unchecked")
057        private <T> T doConvertTo(Class<T> type, Exchange exchange, Object value) throws Exception {
058            // do not convert to stream cache
059            if (StreamCache.class.isAssignableFrom(value.getClass())) {
060                return null;
061            }
062    
063            if (Future.class.isAssignableFrom(value.getClass())) {
064    
065                Future<?> future = (Future<?>) value;
066    
067                if (future.isCancelled()) {
068                    // return void to indicate its not possible to convert at this time
069                    return (T) Void.TYPE;
070                }
071    
072                // do some trace logging as the get is blocking until the response is ready
073                LOG.trace("Getting future response");
074    
075                Object body = future.get();
076                LOG.trace("Got future response");
077    
078                if (body == null) {
079                    // return void to indicate its not possible to convert at this time
080                    return (T) Void.TYPE;
081                }
082    
083                // maybe from is already the type we want
084                if (type.isAssignableFrom(body.getClass())) {
085                    return type.cast(body);
086                } else if (body instanceof Exchange) {
087                    Exchange result = (Exchange) body;
088                    body = ExchangeHelper.extractResultBody(result, result.getPattern());
089                }
090    
091                // no then convert to the type
092                return converter.convertTo(type, exchange, body);
093            }
094    
095            return null;
096        }
097    
098    }