io.aeron.command.PublicationMessageFlyweight Maven / Gradle / Ivy
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/*
* Copyright 2014-2024 Real Logic Limited.
*
* 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
*
* https://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 io.aeron.command;
import io.aeron.exceptions.ControlProtocolException;
import org.agrona.MutableDirectBuffer;
import static io.aeron.ErrorCode.MALFORMED_COMMAND;
import static org.agrona.BitUtil.SIZE_OF_INT;
import static org.agrona.BitUtil.SIZE_OF_LONG;
/**
* Control message for adding or removing a publication
*
* 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
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Client ID |
* | |
* +---------------------------------------------------------------+
* | Correlation ID |
* | |
* +---------------------------------------------------------------+
* | Stream ID |
* +---------------------------------------------------------------+
* | Channel Length |
* +---------------------------------------------------------------+
* | Channel (ASCII) ...
* ... |
* +---------------------------------------------------------------+
*
*/
public class PublicationMessageFlyweight extends CorrelatedMessageFlyweight
{
private static final int STREAM_ID_FIELD_OFFSET = CORRELATION_ID_FIELD_OFFSET + SIZE_OF_LONG;
private static final int CHANNEL_OFFSET = STREAM_ID_FIELD_OFFSET + SIZE_OF_INT;
private static final int MINIMUM_LENGTH = CHANNEL_OFFSET + SIZE_OF_INT;
private int lengthOfChannel;
/**
* Wrap the buffer at a given offset for updates.
*
* @param buffer to wrap.
* @param offset at which the message begins.
* @return this for a fluent API.
*/
public PublicationMessageFlyweight wrap(final MutableDirectBuffer buffer, final int offset)
{
super.wrap(buffer, offset);
return this;
}
/**
* Get the stream id field.
*
* @return stream id field.
*/
public int streamId()
{
return buffer.getInt(offset + STREAM_ID_FIELD_OFFSET);
}
/**
* Set the stream id field.
*
* @param streamId field value.
* @return this for a fluent API.
*/
public PublicationMessageFlyweight streamId(final int streamId)
{
buffer.putInt(offset + STREAM_ID_FIELD_OFFSET, streamId);
return this;
}
/**
* Get the channel field in ASCII.
*
* @return channel field.
*/
public String channel()
{
return buffer.getStringAscii(offset + CHANNEL_OFFSET);
}
/**
* Append the channel value to an {@link Appendable}.
*
* @param appendable to append channel to.
*/
public void appendChannel(final Appendable appendable)
{
buffer.getStringAscii(offset + CHANNEL_OFFSET, appendable);
}
/**
* Set the channel field in ASCII.
*
* @param channel field value.
* @return this for a fluent API.
*/
public PublicationMessageFlyweight channel(final String channel)
{
lengthOfChannel = buffer.putStringAscii(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;
}
/**
* Validate buffer length is long enough for message.
*
* @param msgTypeId type of message.
* @param length of message in bytes to validate.
*/
public void validateLength(final int msgTypeId, final int length)
{
if (length < MINIMUM_LENGTH)
{
throw new ControlProtocolException(
MALFORMED_COMMAND, "command=" + msgTypeId + " too short: length=" + length);
}
if ((length - MINIMUM_LENGTH) < buffer.getInt(offset + CHANNEL_OFFSET))
{
throw new ControlProtocolException(
MALFORMED_COMMAND, "command=" + msgTypeId + " too short for channel: length=" + length);
}
}
/**
* Compute the length of the command message for a given channel length.
*
* @param channelLength to be appended to the header.
* @return the length of the command message for a given channel length.
*/
public static int computeLength(final int channelLength)
{
return MINIMUM_LENGTH + channelLength;
}
}