org.apache.htrace.core

Class TracerPool

java.lang.Object

org.apache.htrace.core.TracerPool

public class TracerPool
extends Object

A pool of Tracer objects. There may be more than one Tracer running inside a single 'process'; for example, unit tests may spin up a DataNode, a NameNode, and HDFS clients all running in a single JVM instance, each with its own Tracer. TracerPool is where all Tracer instances register on creation so Tracers can coordinate around shared resources such as SpanReceiver instances. TracerPool takes care of properly cleaning up registered Tracer instances on shutdown.

Constructor Summary

Constructors

Constructor and Description
TracerPool(String name)

Method Summary

Modifier and Type	Method and Description
boolean	addReceiver(SpanReceiver receiver) Add a new span receiver.
static TracerPool	getGlobalTracerPool() Get the global tracer pool.
String	getName() Return the name of this TracerPool.
SpanReceiver[]	getReceivers() Returns an array of all the current span receivers.
Tracer[]	getTracers() Returns an array of all the current Tracers.
SpanReceiver	loadReceiverType(String className, HTraceConfiguration conf, ClassLoader classLoader) Given a SpanReceiver class name, return the existing instance of that span receiver, if possible; otherwise, invoke the callable to create a new instance.
boolean	removeAndCloseReceiver(SpanReceiver receiver) Remove and close a span receiver.
boolean	removeReceiver(SpanReceiver receiver) Remove a span receiver.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

TracerPool

public TracerPool(String name)

Method Detail

getGlobalTracerPool

public static TracerPool getGlobalTracerPool()

Get the global tracer pool.

Returns:

The tracer pool.

getName

public String getName()

Return the name of this TracerPool.

Returns:

The name.

getReceivers

public SpanReceiver[] getReceivers()

Returns an array of all the current span receivers. Note that if the current span receivers change, those changes will not be reflected in this array. In other words, this array may be stale.

Returns:

An array of the current span receivers.

addReceiver

public boolean addReceiver(SpanReceiver receiver)

Add a new span receiver.

Parameters:

receiver - The new receiver to add.

Returns:

True if the new receiver was added; false if it already was there.

removeReceiver

public boolean removeReceiver(SpanReceiver receiver)

Remove a span receiver.

Parameters:

receiver - The receiver to remove.

Returns:

True if the receiver was removed; false if it did not exist in this pool.

removeAndCloseReceiver

public boolean removeAndCloseReceiver(SpanReceiver receiver)

Remove and close a span receiver.

Parameters:

receiver - The receiver to remove.

Returns:

True if the receiver was removed; false if it did not exist in this pool.

loadReceiverType

public SpanReceiver loadReceiverType(String className,
                                     HTraceConfiguration conf,
                                     ClassLoader classLoader)

Given a SpanReceiver class name, return the existing instance of that span receiver, if possible; otherwise, invoke the callable to create a new instance.

Parameters:

className - The span receiver class name.

conf - The HTrace configuration.

classLoader - The class loader to use.

Returns:

The SpanReceiver.

getTracers

public Tracer[] getTracers()

Returns an array of all the current Tracers. Note that if the current Tracers change, those changes will not be reflected in this array. In other words, this array may be stale.

Returns:

The current array of tracers.

toString

public String toString()

Overrides:

toString in class Object