/*
* 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.synapse.transport.pipe;
import java.io.ByteArrayOutputStream;
import java.util.LinkedList;
import java.util.Queue;
import org.apache.axis2.AxisFault;
import org.apache.axis2.description.ParameterInclude;
import org.apache.axis2.transport.base.ParamUtils;
/**
* End delimited protocol implementation.
* <p>
* In the end delimited protocol datagrams are encapsulated in the stream
* without modification. After each datagram an end byte is appended.
* Since datagrams may contain arbitrary byte sequences and no escape
* algorithm is defined, this protocol is only suitable if it can be assumed
* that the end byte never appears inside a datagram.
* <p>
* This protocol implementation is mainly useful with legacy protocols.
* For example, in conjunction with {@link PipeListener} and
* {@link org.apache.synapse.format.syslog.SyslogMessageBuilder} it can be
* used to receive syslog events via a UNIX pipe. In this case the end byte
* is 10.
* <p>
* This protocol recognizes a single mandatory parameter <tt>delimiter</tt>
* that must be configured in the transport and that specifies the end byte.
* The value must be given as an integer. An example transport receiver
* configuration looks like:
* <pre>
* <transportReceiver name="pipe" class="org.apache.synapse.transport.pipe.PipeListener">
* <parameter name="protocol">org.apache.synapse.transport.pipe.EndDelimitedProtocol</parameter>
* <parameter name="delimiter">10</parameter>
* </transportReceiver></pre>
*/
public class EndDelimitedProtocol implements Protocol {
private class ProtocolDecoderImpl implements ProtocolDecoder {
private final ByteArrayOutputStream messageBuffer = new ByteArrayOutputStream();
private final Queue<byte[]> messages = new LinkedList<byte[]>();
public ProtocolDecoderImpl() {}
public boolean inputRequired() {
return messages.isEmpty();
}
public void decode(byte[] buf, int offset, int length) {
byte delimiter = getDelimiter();
int start = offset;
for (int i=offset; i<length; i++) {
if (buf[i] == delimiter) {
messageBuffer.write(buf, start, i-start);
start = i+1;
messages.add(messageBuffer.toByteArray());
messageBuffer.reset();
}
}
messageBuffer.write(buf, start, length-start);
}
public byte[] getNext() {
return messages.poll();
}
}
private byte delimiter;
public void init(ParameterInclude paramInclude) throws AxisFault {
delimiter = (byte)ParamUtils.getRequiredParamInt(paramInclude, "delimiter");
}
public byte getDelimiter() {
return delimiter;
}
public void setDelimiter(byte delimiter) {
this.delimiter = delimiter;
}
public ProtocolDecoder createProtocolDecoder() {
return new ProtocolDecoderImpl();
}
}