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.ExecutionException;
020 import java.util.concurrent.Future;
021
022 import org.apache.camel.Converter;
023 import org.apache.camel.Exchange;
024 import org.apache.camel.NoTypeConversionAvailableException;
025 import org.apache.camel.StreamCache;
026 import org.apache.camel.TypeConverter;
027 import org.apache.camel.util.ExchangeHelper;
028 import org.apache.camel.util.ObjectHelper;
029 import org.apache.commons.logging.Log;
030 import org.apache.commons.logging.LogFactory;
031
032 /**
033 * Future type converter.
034 *
035 * @version $Revision: 772853 $
036 */
037 @Converter
038 public final class FutureTypeConverter implements TypeConverter {
039
040 private static final Log LOG = LogFactory.getLog(FutureTypeConverter.class);
041
042 private final TypeConverter converter;
043
044 public FutureTypeConverter(TypeConverter converter) {
045 this.converter = converter;
046 }
047
048 private <T> T doConvertTo(Class<T> type, Exchange exchange, Object value) throws Exception {
049 // do not convert to stream cache
050 if (StreamCache.class.isAssignableFrom(value.getClass())) {
051 return null;
052 }
053
054 if (Future.class.isAssignableFrom(value.getClass())) {
055
056 Future future = (Future) value;
057
058 if (future.isCancelled()) {
059 return null;
060 }
061
062 // do some trace logging as the get is blocking until the response is ready
063 if (LOG.isTraceEnabled()) {
064 LOG.trace("Getting future response");
065 }
066
067 Object body;
068 try {
069 body = future.get();
070 } catch (ExecutionException e) {
071 if (e.getCause() instanceof Exception) {
072 throw (Exception) e.getCause();
073 } else {
074 throw e;
075 }
076 }
077 if (LOG.isTraceEnabled()) {
078 LOG.trace("Got future response");
079 }
080
081 if (body == null) {
082 return null;
083 }
084
085 // maybe from is already the type we want
086 if (type.isAssignableFrom(body.getClass())) {
087 return type.cast(body);
088 } else if (body instanceof Exchange) {
089 Exchange result = (Exchange) body;
090 body = ExchangeHelper.extractResultBody(result, result.getPattern());
091 }
092
093 // no then try to lookup a type converter
094 return converter.convertTo(type, exchange, body);
095 }
096
097 return null;
098 }
099
100 public <T> T convertTo(Class<T> type, Object value) {
101 return convertTo(type, null, value);
102 }
103
104 public <T> T convertTo(Class<T> type, Exchange exchange, Object value) {
105 try {
106 return doConvertTo(type, exchange, value);
107 } catch (Exception e) {
108 throw ObjectHelper.wrapRuntimeCamelException(e);
109 }
110 }
111
112 public <T> T mandatoryConvertTo(Class<T> type, Object value) throws NoTypeConversionAvailableException {
113 return mandatoryConvertTo(type, null, value);
114 }
115
116 public <T> T mandatoryConvertTo(Class<T> type, Exchange exchange, Object value) throws NoTypeConversionAvailableException {
117 T answer;
118 try {
119 answer = doConvertTo(type, exchange, value);
120 } catch (Exception e) {
121 throw new NoTypeConversionAvailableException(value, type, e);
122 }
123
124 if (answer == null) {
125 throw new NoTypeConversionAvailableException(value, type);
126 }
127
128 return answer;
129 }
130 }