/*
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.qpid.management.messages;
import java.io.IOException;
import java.nio.ByteBuffer;
import org.apache.qpid.api.Message;
import org.apache.qpid.management.configuration.Configuration;
import org.apache.qpid.management.domain.services.SequenceNumberGenerator;
import org.apache.qpid.transport.DeliveryProperties;
import org.apache.qpid.transport.Header;
import org.apache.qpid.transport.MessageProperties;
import org.apache.qpid.transport.codec.BBEncoder;
/**
* Message implementation used for specific management purposes.
*
* @author Andrea Gazzarini
*/
public abstract class ManagementMessage implements Message
{
/**
* Strategy interface for building / getting data.
*
* @author Andrea Gazzarini
*/
private interface IDataBuilderStrategy
{
ByteBuffer getData();
};
/**
* Strategy used for retrieving raw data from this message when it has been already encoded.
*/
IDataBuilderStrategy READING = new IDataBuilderStrategy()
{
public ByteBuffer getData() {
return _data;
};
};
/**
* Strategy used for retrieving raw data from this message when it hasn't been already encoded.
*/
IDataBuilderStrategy ACCUMULATING = new IDataBuilderStrategy()
{
public ByteBuffer getData() {
_codec.writeInt8((byte)opcode());
_codec.writeSequenceNo(sequenceNumber());
specificMessageEncoding();
_data =_codec.segment();
_reader = READING;
return _data;
}
};
protected BBEncoder _codec;
protected ByteBuffer _data;
private int _messageTransferId;
private IDataBuilderStrategy _reader = ACCUMULATING;
/**
* Builds an empty management message.
*/
ManagementMessage()
{
_codec = new BBEncoder(100);
_codec.writeMagicNumber();
}
/**
* Returns the sequence number that will be used for this message.
*
* @return the sequence number that will be used for this message.
*/
protected int sequenceNumber ()
{
return SequenceNumberGenerator.getNextSequenceNumber();
}
/**
* Returns the opcode that will be used for this message.
*
* @return the opcode that will be used for this message.
*/
abstract char opcode ();
/**
* Returns the delivery properties of this message.
*
* @return the delivery properties of this message.
*/
public DeliveryProperties getDeliveryProperties ()
{
return Configuration.getInstance().getCommandDeliveryProperties();
}
/**
* Returns the header of this message.
*
* @return the header of this message.
*/
public Header getHeader ()
{
return Configuration.getInstance().getCommandMessageHeader();
}
/**
* Returns the messages header properties of this message.
*
* @return the message header properties of this message.
*/
public MessageProperties getMessageProperties ()
{
return Configuration.getInstance().getCommandMessageProperties();
}
/**
* Returns the transfer Id of this message.
*
* @return the transfer Id of this message.
*/
public int getMessageTransferId ()
{
return _messageTransferId;
}
/**
* Returns the encoded data of this message.
*
* @return the encoded data of this message.
*/
public ByteBuffer readData () throws IOException
{
return _reader.getData();
}
/**
* Sets the header for this message.
*
* @param header the new message header.
*/
public void setHeader (Header header)
{
// N.A. at the moment.
}
public void appendData (byte[] src) throws IOException
{
}
public void appendData (ByteBuffer src) throws IOException
{
}
public void clearData ()
{
}
public void readData (byte[] target) throws IOException
{
}
/**
* Concrete subclasses (message implementations) must define here their specific data encoding.
*/
abstract void specificMessageEncoding();
}