uk.co.real_logic.aeron.command.ImageMessageFlyweight Maven / Gradle / Ivy
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/*
* Copyright 2014 - 2016 Real Logic 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 uk.co.real_logic.aeron.command;
import uk.co.real_logic.agrona.MutableDirectBuffer;
import static uk.co.real_logic.agrona.BitUtil.SIZE_OF_INT;
/**
* Control message flyweight for any message that needs to represent a connection
*
*
* 0 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Correlation ID |
* | |
* +---------------------------------------------------------------+
* | Stream ID |
* +---------------------------------------------------------------+
* | Channel Length |
* +---------------------------------------------------------------+
* | Channel ...
* ... |
* +---------------------------------------------------------------+
*/
public class ImageMessageFlyweight
{
private static final int CORRELATION_ID_OFFSET = 0;
private static final int STREAM_ID_FIELD_OFFSET = 8;
private static final int CHANNEL_OFFSET = 12;
private MutableDirectBuffer buffer;
private int offset;
private int lengthOfChannel;
/**
* Wrap the buffer at a given offset for updates.
*
* @param buffer to wrap
* @param offset at which the message begins.
* @return for fluent API
*/
public final ImageMessageFlyweight wrap(final MutableDirectBuffer buffer, final int offset)
{
this.buffer = buffer;
this.offset = offset;
return this;
}
/**
* return correlation id field
* @return correlation id field
*/
public long correlationId()
{
return buffer.getLong(offset + CORRELATION_ID_OFFSET);
}
/**
* set correlation id field
* @param correlationId field value
* @return flyweight
*/
public ImageMessageFlyweight correlationId(final long correlationId)
{
buffer.putLong(offset + CORRELATION_ID_OFFSET, correlationId);
return this;
}
/**
* return stream id field
*
* @return stream id field
*/
public int streamId()
{
return buffer.getInt(offset + STREAM_ID_FIELD_OFFSET);
}
/**
* set stream id field
*
* @param streamId field value
* @return flyweight
*/
public ImageMessageFlyweight streamId(final int streamId)
{
buffer.putInt(offset + STREAM_ID_FIELD_OFFSET, streamId);
return this;
}
/**
* return channel field
*
* @return channel field
*/
public String channel()
{
final int length = buffer.getInt(offset + CHANNEL_OFFSET);
lengthOfChannel = SIZE_OF_INT + length;
return buffer.getStringUtf8(offset + CHANNEL_OFFSET, length);
}
/**
* set channel field
*
* @param channel field value
* @return flyweight
*/
public ImageMessageFlyweight channel(final String channel)
{
lengthOfChannel = buffer.putStringUtf8(offset + CHANNEL_OFFSET, channel);
return this;
}
/**
* Get the length of the current message
*
* NB: must be called after the data is written in order to be accurate.
*
* @return the length of the current message
*/
public int length()
{
return CHANNEL_OFFSET + lengthOfChannel;
}
}