org.apache.mesos

Class Log.Writer

java.lang.Object

org.apache.mesos.Log.Writer

Enclosing class:

Log

public static class Log.Writer
extends Object

Provides write access to the Log. This class is not safe for use from multiple threads and instances should be thrown out after any Log.WriterFailedException is thrown.

Constructor Summary

Constructors

Constructor and Description
Log.Writer(Log log, long timeout, TimeUnit unit, int retries) Constructs a writer linked the given Log.

Method Summary

Methods

Modifier and Type	Method and Description
Log.Position	append(byte[] data, long timeout, TimeUnit unit) Attempts to append to the log with the specified data returning the new end position of the log if successful.
protected void	finalize()
protected void	initialize(Log log, long timeout, TimeUnit unit, int retries)
Log.Position	truncate(Log.Position to, long timeout, TimeUnit unit) Attempts to truncate the log (from the beginning to the specified position exclusive) If the position is invalid, an Log.WriterFailedException will get thrown.

Methods inherited from class java.lang.Object

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

Constructor Detail

Log.Writer

public Log.Writer(Log log,
          long timeout,
          TimeUnit unit,
          int retries)

Constructs a writer linked the given Log.

Parameters:

log - The log that this writer will access.

timeout - Max number of time units to wait before a TimeoutException.

unit - Type of time units used for the timeout, e.g. seconds, minutes, etc.

retries - Number of retries

See Also:

TimeUnit

Method Detail

append

public Log.Position append(byte[] data,
                  long timeout,
                  TimeUnit unit)
                    throws TimeoutException,
                           Log.WriterFailedException

Attempts to append to the log with the specified data returning the new end position of the log if successful.

Parameters:

data - Data to append to the log.

timeout - Max number of time units to wait before a TimeoutException.

unit - Type of time units used for the timeout, e.g. seconds, minutes, etc.

Returns:

The new end-position.

Throws:

TimeoutException - If the append doesn't happen before the timeout.

Log.WriterFailedException - If the append fails due that the writer no longer has the ability to perform its operations (e.g., because it was superseded by another writer).

See Also:

TimeUnit, Log.WriterFailedException

truncate

public Log.Position truncate(Log.Position to,
                    long timeout,
                    TimeUnit unit)
                      throws TimeoutException,
                             Log.WriterFailedException

Attempts to truncate the log (from the beginning to the specified position exclusive) If the position is invalid, an Log.WriterFailedException will get thrown. Unfortunately, this will also get thrown in other circumstances (e.g., disk failure) and therefore it is currently impossible to tell these two cases apart.

Parameters:

to - The log will be truncated up to this point.

timeout - Max number of time units to wait before a TimeoutException.

unit - Type of time units used for the timeout, e.g. seconds, minutes, etc.

Returns:

The position after the truncation.

Throws:

TimeoutException - If the truncation doesn't happen before the timeout.

Log.WriterFailedException - If the truncation fails due an invalid position or if the writer no longer has the ability to perform its operations (e.g., because it was superseded by another writer).

initialize

protected void initialize(Log log,
              long timeout,
              TimeUnit unit,
              int retries)

finalize

protected void finalize()

Overrides:

finalize in class Object