ManyToOneRingBuffer (Agrona)

java.lang.Object
- org.agrona.concurrent.ringbuffer.ManyToOneRingBuffer

All Implemented Interfaces:

RingBuffer
```
public class ManyToOneRingBuffer
extends java.lang.Object
implements RingBuffer
```
A ring-buffer that supports the exchange of messages from many producers to a single consumer.

Field Summary

Fields
Modifier and Type Field and Description

static int PADDING_MSG_TYPE_ID
Record type is padding to prevent fragmentation in the buffer.

Fields
Modifier and Type	Field and Description
`static int`	`PADDING_MSG_TYPE_ID` Record type is padding to prevent fragmentation in the buffer.

Constructor Summary

Constructors
Constructor and Description

ManyToOneRingBuffer(AtomicBuffer buffer)
Construct a new RingBuffer based on an underlying AtomicBuffer.

Constructors
Constructor and Description
`ManyToOneRingBuffer(AtomicBuffer buffer)` Construct a new `RingBuffer` based on an underlying `AtomicBuffer`.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`AtomicBuffer`	`buffer()` Get the underlying buffer used by the RingBuffer for storage.
`int`	`capacity()` Get the capacity of the ring-buffer in bytes for exchange.
`long`	`consumerHeartbeatTime()` The time of the last consumer heartbeat.
`void`	`consumerHeartbeatTime(long time)` Set the time of the last consumer heartbeat.
`long`	`consumerPosition()` The position in bytes from start up for the consumers.
`int`	`maxMsgLength()` The maximum message length in bytes supported by the underlying ring buffer.
`long`	`nextCorrelationId()` Get the next value that can be used for a correlation id on an message when a response needs to be correlated.
`long`	`producerPosition()` The position in bytes from start up of the producers.
`int`	`read(MessageHandler handler)` Read as many messages as are available to the end of the ring buffer.
`int`	`read(MessageHandler handler, int messageCountLimit)` Read as many messages as are available to end of the ring buffer to up a supplied maximum.
`int`	`size()` Size of the buffer backlog in bytes between producers and consumers.
`boolean`	`unblock()` Unblock a multi-producer ring buffer when a producer has died during the act of offering.
`boolean`	`write(int msgTypeId, DirectBuffer srcBuffer, int srcIndex, int length)` Non-blocking write of an message to an underlying ring-buffer.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - PADDING_MSG_TYPE_ID
```
public static final int PADDING_MSG_TYPE_ID
```
    Record type is padding to prevent fragmentation in the buffer.
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - ManyToOneRingBuffer
```
public ManyToOneRingBuffer(AtomicBuffer buffer)
```
    Construct a new RingBuffer based on an underlying AtomicBuffer. The underlying buffer must a power of 2 in size plus sufficient space for the RingBufferDescriptor.TRAILER_LENGTH.
    
    Parameters:
    
    buffer - via which events will be exchanged.
    
    Throws:
    
    java.lang.IllegalStateException - if the buffer capacity is not a power of 2 plus RingBufferDescriptor.TRAILER_LENGTH in capacity.
- Method Detail
  - capacity
```
public int capacity()
```
    Get the capacity of the ring-buffer in bytes for exchange.
    
    Specified by:
    
    capacity in interface RingBuffer
    
    Returns:
    
    the capacity of the ring-buffer in bytes for exchange.
  - write
```
public boolean write(int msgTypeId,
                     DirectBuffer srcBuffer,
                     int srcIndex,
                     int length)
```
    Non-blocking write of an message to an underlying ring-buffer.
    
    Specified by:
    
    write in interface RingBuffer
    
    Parameters:
    
    msgTypeId - type of the message encoding.
    
    srcBuffer - containing the encoded binary message.
    
    srcIndex - at which the encoded message begins.
    
    length - of the encoded message in bytes.
    
    Returns:
    
    true if written to the ring-buffer, or false if insufficient space exists.
  - read
```
public int read(MessageHandler handler)
```
    Read as many messages as are available to the end of the ring buffer.
    If the ring buffer wraps or encounters a type of record, such a a padding record, then an implementation may choose to return and expect the caller to try again. The RingBuffer.size() method may be called to determine of a backlog of message bytes remains in the ring buffer.
    
    Specified by:
    
    read in interface RingBuffer
    
    Parameters:
    
    handler - to be called for processing each message in turn.
    
    Returns:
    
    the number of messages that have been processed.
  - read
```
public int read(MessageHandler handler,
                int messageCountLimit)
```
    Read as many messages as are available to end of the ring buffer to up a supplied maximum.
    If the ring buffer wraps or encounters a type of record, such a a padding record, then an implementation may choose to return and expect the caller to try again. The RingBuffer.size() method may be called to determine of a backlog of message bytes remains in the ring buffer.
    
    Specified by:
    
    read in interface RingBuffer
    
    Parameters:
    
    handler - to be called for processing each message in turn.
    
    messageCountLimit - the number of messages will be read in a single invocation.
    
    Returns:
    
    the number of messages that have been processed.
  - maxMsgLength
```
public int maxMsgLength()
```
    The maximum message length in bytes supported by the underlying ring buffer.
    
    Specified by:
    
    maxMsgLength in interface RingBuffer
    
    Returns:
    
    the maximum message length in bytes supported by the underlying ring buffer.
  - nextCorrelationId
```
public long nextCorrelationId()
```
    Get the next value that can be used for a correlation id on an message when a response needs to be correlated.
    This method should be thread safe.
    
    Specified by:
    
    nextCorrelationId in interface RingBuffer
    
    Returns:
    
    the next value in the correlation sequence.
  - buffer
```
public AtomicBuffer buffer()
```
    Get the underlying buffer used by the RingBuffer for storage.
    
    Specified by:
    
    buffer in interface RingBuffer
    
    Returns:
    
    the underlying buffer used by the RingBuffer for storage.
  - consumerHeartbeatTime
```
public void consumerHeartbeatTime(long time)
```
    Set the time of the last consumer heartbeat.
    Note: The value for time must be valid across processes which means System.nanoTime() is not a valid option.
    
    Specified by:
    
    consumerHeartbeatTime in interface RingBuffer
    
    Parameters:
    
    time - of the last consumer heartbeat.
  - consumerHeartbeatTime
```
public long consumerHeartbeatTime()
```
    The time of the last consumer heartbeat.
    
    Specified by:
    
    consumerHeartbeatTime in interface RingBuffer
    
    Returns:
    
    the time of the last consumer heartbeat.
  - producerPosition
```
public long producerPosition()
```
    The position in bytes from start up of the producers. The figure includes the headers. This is the range they are working with but could still be in the act of working with.
    
    Specified by:
    
    producerPosition in interface RingBuffer
    
    Returns:
    
    number of bytes produced by the producers in claimed space.
  - consumerPosition
```
public long consumerPosition()
```
    The position in bytes from start up for the consumers. The figure includes the headers.
    
    Specified by:
    
    consumerPosition in interface RingBuffer
    
    Returns:
    
    the count of bytes consumed by the consumers.
  - size
```
public int size()
```
    Size of the buffer backlog in bytes between producers and consumers. The value includes the size of headers.
    This method gives a concurrent snapshot of the buffer whereby a concurrent read or write may be partially complete and thus the value should be taken as an indication.
    
    Specified by:
    
    size in interface RingBuffer
    
    Returns:
    
    size of the backlog of bytes in the buffer between producers and consumers.
  - unblock
```
public boolean unblock()
```
    Unblock a multi-producer ring buffer when a producer has died during the act of offering. The operation will scan from the consumer position up to the producer position.
    If no action is required at the position then none will be taken.
    
    Specified by:
    
    unblock in interface RingBuffer
    
    Returns:
    
    true of an unblocking action was taken otherwise false.

Class ManyToOneRingBuffer

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

PADDING_MSG_TYPE_ID

Constructor Detail

ManyToOneRingBuffer

Method Detail

capacity

write

read

read

maxMsgLength

nextCorrelationId

buffer

consumerHeartbeatTime

consumerHeartbeatTime

producerPosition

consumerPosition

size

unblock