Package com.wavefront.agent.queueing

Class FileBasedTaskQueue<T extends DataSubmissionTask<T>>

java.lang.Object

com.wavefront.agent.queueing.FileBasedTaskQueue<T>

Type Parameters:

T - type of objects stored.

All Implemented Interfaces:

TaskQueue<T>, Iterable<T>

public class FileBasedTaskQueue<T extends DataSubmissionTask<T>>
extends Object
implements TaskQueue<T>

Implements proxy-specific TaskQueue interface as a wrapper over QueueFile.

Author:

[email protected]

Constructor Summary

Constructors

Constructor	Description
FileBasedTaskQueue(QueueFile queueFile, TaskConverter<T> taskConverter)

Method Summary

Modifier and Type	Method	Description
void	add(T entry)	Add a task to the end of the queue
void	clear()	Empty and re-initialize the queue.
void	close()	Close the queue.
Long	getAvailableBytes()	Returns the total number of pre-allocated but unused bytes in the backing file.
Iterator<T>	iterator()
T	peek()	Retrieve a task that is currently at the head of the queue.
void	remove()	Remove a task from the head of the queue.
int	size()	Returns a number of tasks currently in the queue.
Long	weight()	Returns the total weight of the queue (sum of weights of all tasks).

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

FileBasedTaskQueue

public FileBasedTaskQueue(QueueFile queueFile,
                          TaskConverter<T> taskConverter)

Parameters:

queueFile - file backing the queue

taskConverter - task converter

Method Detail

peek

public T peek()

Description copied from interface: TaskQueue

Retrieve a task that is currently at the head of the queue.

Specified by:

peek in interface TaskQueue<T extends DataSubmissionTask<T>>

Returns:

task object

add

public void add(@Nonnull
                T entry)
         throws IOException

Description copied from interface: TaskQueue

Add a task to the end of the queue

Specified by:

add in interface TaskQueue<T extends DataSubmissionTask<T>>

Parameters:

entry - task

Throws:

IOException - IO exceptions caught by the storage engine

clear

public void clear()
           throws IOException

Description copied from interface: TaskQueue

Empty and re-initialize the queue.

Specified by:

clear in interface TaskQueue<T extends DataSubmissionTask<T>>

Throws:

IOException

remove

public void remove()
            throws IOException

Description copied from interface: TaskQueue

Remove a task from the head of the queue. Requires peek() to be called first, otherwise an IllegalStateException is thrown.

Specified by:

remove in interface TaskQueue<T extends DataSubmissionTask<T>>

Throws:

IOException - IO exceptions caught by the storage engine

size

public int size()

Description copied from interface: TaskQueue

Returns a number of tasks currently in the queue.

Specified by:

size in interface TaskQueue<T extends DataSubmissionTask<T>>

Returns:

number of tasks

close

public void close()
           throws IOException

Description copied from interface: TaskQueue

Close the queue. Should be invoked before a graceful shutdown.

Specified by:

close in interface TaskQueue<T extends DataSubmissionTask<T>>

Throws:

IOException

weight

@Nullable
public Long weight()

Description copied from interface: TaskQueue

Returns the total weight of the queue (sum of weights of all tasks).

Specified by:

weight in interface TaskQueue<T extends DataSubmissionTask<T>>

Returns:

weight of the queue (null if unknown)

getAvailableBytes

@Nullable
public Long getAvailableBytes()

Description copied from interface: TaskQueue

Returns the total number of pre-allocated but unused bytes in the backing file. May return null if not applicable.

Specified by:

getAvailableBytes in interface TaskQueue<T extends DataSubmissionTask<T>>

Returns:

total number of available bytes in the file or null

iterator

@Nonnull
public Iterator<T> iterator()

Specified by:

iterator in interface Iterable<T extends DataSubmissionTask<T>>