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.converter;
018
019import java.util.concurrent.Future;
020
021import org.apache.camel.Converter;
022import org.apache.camel.Exchange;
023import org.apache.camel.StreamCache;
024import org.apache.camel.TypeConversionException;
025import org.apache.camel.TypeConverter;
026import org.apache.camel.support.TypeConverterSupport;
027import org.apache.camel.util.ExchangeHelper;
028import org.slf4j.Logger;
029import org.slf4j.LoggerFactory;
030
031/**
032 * Future type converter.
033 *
034 * @version 
035 */
036@Converter
037public 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}