/**
*
* Copyright 2004 Protique Ltd
*
* 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.activemq.io;
import java.io.DataInputStream;
import java.io.IOException;
import javax.jms.JMSException;
import org.activemq.io.impl.DefaultWireFormat;
import org.activemq.util.FactoryFinder;
/**
* Represents a strategy of encoding packets on the wire or on disk using some kind of serialization or wire format.
* <p/>We use a default efficient format for Java to Java communication but other formats to other systems can be used,
* such as using simple text strings when talking to JavaScript or coming up with other formats for talking to C / C#
* languages or proprietary messaging systems we wish to interface with at the wire level etc.
*
* @version $Revision: 1.1.1.1 $
*/
public class WireFormatLoader {
private static FactoryFinder finder = new FactoryFinder("META-INF/services/org/activemq/io/");
private WireFormat preferedWireFormat;
/**
* Default Constructor
*/
public WireFormatLoader() {
this(new DefaultWireFormat());
}
/**
* Construct WireFormatLoader with the prefered WireFormat
*
* @param prefered
*/
public WireFormatLoader(WireFormat prefered) {
this.preferedWireFormat = prefered;
}
/**
* Create a wire format
*
* @param dataIn
* @return the WireFormat
* @throws JMSException
* @throws IOException
*/
public WireFormat getWireFormat(DataInputStream dataIn) throws JMSException, IOException {
WireFormat result = preferedWireFormat;
dataIn.mark(10);
int protocol = dataIn.read();
if (protocol == 128) {
//tis amqfast
result = WireFormatLoader.getWireFormat("amqpfast");
}
dataIn.reset();
return result;
}
/**
* @return Returns the preferedWireFormat.
*/
public WireFormat getPreferedWireFormat() {
return preferedWireFormat;
}
/**
* @param preferedWireFormat The preferedWireFormat to set.
*/
public void setPreferedWireFormat(WireFormat preferedWireFormat) {
this.preferedWireFormat = preferedWireFormat;
}
/**
* load a WireFormat by name - e.g. 'default','amqpfast' etc.
*
* @param format
* @return the wire format
* @throws JMSException
*/
public static WireFormat getWireFormat(String format) throws JMSException {
try {
Object value = finder.newInstance(format);
if (value instanceof WireFormat) {
return (WireFormat) value;
}
else {
throw new JMSException(format + " is not a WireFormat: " + value);
}
}
catch (IllegalAccessException e) {
throw createJMSexception(format, e);
}
catch (InstantiationException e) {
throw createJMSexception(format, e);
}
catch (IOException e) {
throw createJMSexception(format, e);
}
catch (ClassNotFoundException e) {
throw createJMSexception(format, e);
}
}
protected static JMSException createJMSexception(String protocol, Exception e) {
JMSException answer = new JMSException("Could not load protocol: " + protocol + ". Reason: " + e);
answer.setLinkedException(e);
return answer;
}
}