LossReport (Aeron Message Transport)

java.lang.Object
- io.aeron.driver.reports.LossReport

public final class LossReport
extends Object

A report of loss events on a message stream.

The provided AtomicBuffer can wrap a memory-mapped file so logging can be out of process. This provides the benefit that if a crash or lockup occurs then the log can be read externally without loss of data.

Note:This class is NOT threadsafe to be used from multiple logging threads.

The error records are recorded to the memory mapped buffer in the following format.

   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
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |R|                    Observation Count                        |
  |                                                               |
  +-+-------------------------------------------------------------+
  |R|                     Total Bytes Lost                        |
  |                                                               |
  +---------------------------------------------------------------+
  |                 First Observation Timestamp                   |
  |                                                               |
  +---------------------------------------------------------------+
  |                  Last Observation Timestamp                   |
  |                                                               |
  +---------------------------------------------------------------+
  |                          Session ID                           |
  +---------------------------------------------------------------+
  |                           Stream ID                           |
  +---------------------------------------------------------------+
  |                 Channel encoded in US-ASCII                  ...
 ...                                                              |
  +---------------------------------------------------------------+
  |                  Source encoded in US-ASCII                  ...
 ...                                                              |
  +---------------------------------------------------------------+

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class LossReport.ReportEntry
Report entry for a specific stream.

Nested Classes
Modifier and Type	Class and Description
`static class`	`LossReport.ReportEntry` Report entry for a specific stream.

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`CHANNEL_OFFSET` Offset within an entry at which the channel field begins.
`static int`	`ENTRY_ALIGNMENT` Alignment to be applied for each entry offset.
`static int`	`FIRST_OBSERVATION_OFFSET` Offset within an entry at which the first observation field begins.
`static int`	`LAST_OBSERVATION_OFFSET` Offset within an entry at which the last observation field begins.
`static int`	`OBSERVATION_COUNT_OFFSET` Offset within an entry at which the observation count begins.
`static int`	`SESSION_ID_OFFSET` Offset within an entry at which the session id field begins.
`static int`	`STREAM_ID_OFFSET` Offset within an entry at which the stream id field begins.
`static int`	`TOTAL_BYTES_LOST_OFFSET` Offset within an entry at which the total bytes field begins.

Constructor Summary

Constructors
Constructor and Description

LossReport(AtomicBuffer buffer)
Create a loss report which wraps a buffer which is ideally memory mapped, so it can be read from another process.

Constructors
Constructor and Description
`LossReport(AtomicBuffer buffer)` Create a loss report which wraps a buffer which is ideally memory mapped, so it can be read from another process.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`LossReport.ReportEntry`	`createEntry(long initialBytesLost, long timestampMs, int sessionId, int streamId, String channel, String source)` Create a new entry for recording loss on a given stream.
`String`	`toString()`

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

- Field Detail
  - ENTRY_ALIGNMENT
```
public static final int ENTRY_ALIGNMENT
```
    Alignment to be applied for each entry offset.
    
    See Also:
    
    Constant Field Values
  - OBSERVATION_COUNT_OFFSET
```
public static final int OBSERVATION_COUNT_OFFSET
```
    Offset within an entry at which the observation count begins.
    
    See Also:
    
    Constant Field Values
  - TOTAL_BYTES_LOST_OFFSET
```
public static final int TOTAL_BYTES_LOST_OFFSET
```
    Offset within an entry at which the total bytes field begins.
    
    See Also:
    
    Constant Field Values
  - FIRST_OBSERVATION_OFFSET
```
public static final int FIRST_OBSERVATION_OFFSET
```
    Offset within an entry at which the first observation field begins.
    
    See Also:
    
    Constant Field Values
  - LAST_OBSERVATION_OFFSET
```
public static final int LAST_OBSERVATION_OFFSET
```
    Offset within an entry at which the last observation field begins.
    
    See Also:
    
    Constant Field Values
  - SESSION_ID_OFFSET
```
public static final int SESSION_ID_OFFSET
```
    Offset within an entry at which the session id field begins.
    
    See Also:
    
    Constant Field Values
  - STREAM_ID_OFFSET
```
public static final int STREAM_ID_OFFSET
```
    Offset within an entry at which the stream id field begins.
    
    See Also:
    
    Constant Field Values
  - CHANNEL_OFFSET
```
public static final int CHANNEL_OFFSET
```
    Offset within an entry at which the channel field begins.
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - LossReport
```
public LossReport(AtomicBuffer buffer)
```
    Create a loss report which wraps a buffer which is ideally memory mapped, so it can be read from another process.
    
    Parameters:
    
    buffer - to be wrapped.
- Method Detail
  - createEntry
```
public LossReport.ReportEntry createEntry(long initialBytesLost,
                                          long timestampMs,
                                          int sessionId,
                                          int streamId,
                                          String channel,
                                          String source)
```
    Create a new entry for recording loss on a given stream.
    If not space is remaining in the error report then null is returned.
    
    Parameters:
    
    initialBytesLost - on the stream.
    
    timestampMs - at which the first loss was observed.
    
    sessionId - for the stream.
    
    streamId - for the stream.
    
    channel - for the stream.
    
    source - of the stream.
    
    Returns:
    
    a new record or null if the error log has insufficient space.
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object

Class LossReport

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

ENTRY_ALIGNMENT

OBSERVATION_COUNT_OFFSET

TOTAL_BYTES_LOST_OFFSET

FIRST_OBSERVATION_OFFSET

LAST_OBSERVATION_OFFSET

SESSION_ID_OFFSET

STREAM_ID_OFFSET

CHANNEL_OFFSET

Constructor Detail

LossReport

Method Detail

createEntry

toString