org.springframework.webflow.execution.repository.continuation.SerializedFlowExecutionContinuationFactory Maven / Gradle / Ivy
/*
* Copyright 2002-2006 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.webflow.execution.repository.continuation;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.NotSerializableException;
import java.io.ObjectOutputStream;
import java.util.zip.GZIPOutputStream;
import org.springframework.webflow.execution.FlowExecution;
/**
* A factory that creates new instances of flow execution continuations based on
* standard java serialization.
*
* @author Keith Donald
*/
public class SerializedFlowExecutionContinuationFactory implements FlowExecutionContinuationFactory {
/**
* Flag to toggle continuation compression; compression is on by default.
*/
private boolean compress = true;
/**
* Returns whether or not the continuations should be compressed.
*/
public boolean getCompress() {
return compress;
}
/**
* Set whether or not the continuations should be compressed.
*/
public void setCompress(boolean compress) {
this.compress = compress;
}
public FlowExecutionContinuation createContinuation(FlowExecution flowExecution) throws ContinuationCreationException {
try {
ByteArrayOutputStream baos = new ByteArrayOutputStream(384);
ObjectOutputStream oos = new ObjectOutputStream(baos);
try {
oos.writeObject(flowExecution);
oos.flush();
byte[] data = baos.toByteArray();
if (compress) {
data = compress(data);
}
return new SerializedFlowExecutionContinuation(data, compress);
}
finally {
oos.close();
}
}
catch (NotSerializableException e) {
throw new ContinuationCreationException(flowExecution,
"Could not serialize flow execution; make sure all objects stored in flow scope are serializable",
e);
}
catch (IOException e) {
throw new ContinuationCreationException(flowExecution,
"IOException thrown serializing flow execution -- this should not happen!", e);
}
}
/**
* Internal helper method to compress given data using GZIP compression.
*/
private byte[] compress(byte[] dataToCompress) throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
GZIPOutputStream gzipos = new GZIPOutputStream(baos);
try {
gzipos.write(dataToCompress);
gzipos.flush();
}
finally {
gzipos.close();
}
return baos.toByteArray();
}
}