org.agrona.concurrent.broadcast

Class BroadcastReceiver

java.lang.Object

org.agrona.concurrent.broadcast.BroadcastReceiver

public class BroadcastReceiver
extends Object

Receive messages broadcast from a BroadcastTransmitter via an underlying buffer. Receivers can join a transmission stream at any point by consuming the latest message at the point of joining and forward.

If a Receiver cannot keep up with the transmission stream then loss will be experienced. Loss is not an error condition.

Note: Each Receiver is not threadsafe but there can be zero or many receivers to a transmission stream.

Constructor Summary

Constructors

Constructor and Description
BroadcastReceiver(AtomicBuffer buffer) Construct a new broadcast receiver based on an underlying AtomicBuffer.

Method Summary

Modifier and Type	Method and Description
MutableDirectBuffer	buffer() The underlying buffer containing the broadcast message stream.
int	capacity() Get the capacity of the underlying broadcast buffer.
long	lappedCount() Get the number of times the transmitter has lapped this receiver around the buffer.
int	length() The length of the next message in the transmission stream.
int	offset() The offset for the beginning of the next message in the transmission stream.
boolean	receiveNext() Non-blocking receive of next message from the transmission stream.
int	typeId() Type of the message received.
boolean	validate() Validate that the current received record is still valid and has not been overwritten.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

BroadcastReceiver

public BroadcastReceiver(AtomicBuffer buffer)

Construct a new broadcast receiver based on an underlying AtomicBuffer. The underlying buffer must a power of 2 in size plus sufficient space for the BroadcastBufferDescriptor.TRAILER_LENGTH.

Parameters:

buffer - via which messages will be exchanged.

Throws:

IllegalStateException - if the buffer capacity is not a power of 2 plus BroadcastBufferDescriptor.TRAILER_LENGTH in capacity.

Method Detail

capacity

public int capacity()

Get the capacity of the underlying broadcast buffer.

Returns:

the capacity of the underlying broadcast buffer.

lappedCount

public long lappedCount()

Get the number of times the transmitter has lapped this receiver around the buffer. On each lap as least a buffer's worth of loss will be experienced.

Note: This method is threadsafe for calling from an external monitoring thread.

Returns:

the capacity of the underlying broadcast buffer.

typeId

public int typeId()

Type of the message received.

Returns:

typeId of the message received.

offset

public int offset()

The offset for the beginning of the next message in the transmission stream.

Returns:

offset for the beginning of the next message in the transmission stream.

length

public int length()

The length of the next message in the transmission stream.

Returns:

length of the next message in the transmission stream.

buffer

public MutableDirectBuffer buffer()

The underlying buffer containing the broadcast message stream.

Returns:

the underlying buffer containing the broadcast message stream.

receiveNext

public boolean receiveNext()

Non-blocking receive of next message from the transmission stream.

If loss has occurred then lappedCount() will be incremented.

Returns:

true if transmission is available with offset(), length() and typeId() set for the next message to be consumed. If no transmission is available then false.

validate

public boolean validate()

Validate that the current received record is still valid and has not been overwritten.

If the receiver is not consuming messages fast enough to keep up with the transmitter then loss can be experienced resulting in messages being overwritten thus making them no longer valid.

Returns:

true if still valid otherwise false.