org.apache.manifoldcf.connectorcommon.throttler

Class Throttler

java.lang.Object

org.apache.manifoldcf.connectorcommon.throttler.Throttler

public class Throttler
extends java.lang.Object

A Throttler object creates a virtual pool of connections to resources whose access needs to be throttled in number, rate of use, and byte rate. This code is modeled on the code for distributed connection pools, and is intended to work in a similar manner. Basically, a periodic assessment is done about what the local throttling parameters should be (on a per-pool basis), and the local throttling activities then adjust what they are doing based on the new parameters. A service model is used to keep track of which pools have what clients working with them. This implementation has the advantage that: (1) Only local throttling ever takes place on a method-by-method basis, which makes it possible to use throttling even in streams and background threads; (2) Throttling resources are apportioned fairly, on average, between all the various cluster members, so it is unlikely that any persistent starvation conditions can arise.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	Throttler.ConnectionThrottler Connection throttler implementation class.
protected static class	Throttler.FetchThrottler Fetch throttler implementation class.
protected static class	Throttler.StreamThrottler Stream throttler implementation class.
protected class	Throttler.ThrottlingGroup This class represents a throttling group, of a specific throttling group type.
protected class	Throttler.ThrottlingGroups This class represents a throttling group pool

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	_rcsid
protected java.util.Map<java.lang.String,Throttler.ThrottlingGroups>	throttleGroupsHash Throttle group hash table.

Constructor Summary

Constructors

Constructor and Description
Throttler() Create a throttler instance.

Method Summary

Modifier and Type	Method and Description
protected static java.lang.String	buildThrottlingGroupName(java.lang.String throttlingGroupType, java.lang.String throttlingGroupName)
void	createOrUpdateThrottleGroup(IThreadContext threadContext, java.lang.String throttleGroupType, java.lang.String throttleGroup, IThrottleSpec throttleSpec) Set or update throttle specification for a throttle group.
void	destroy(IThreadContext threadContext) Shut down all throttlers and deregister them.
void	freeUnusedResources(IThreadContext threadContext) Free unused resources.
java.util.Set<java.lang.String>	getThrottleGroups(IThreadContext threadContext, java.lang.String throttleGroupType) Get all existing throttle groups for a throttle group type.
IConnectionThrottler	obtainConnectionThrottler(IThreadContext threadContext, java.lang.String throttleGroupType, java.lang.String throttleGroup, java.lang.String[] binNames) Construct connection throttler for connections with specific bin names.
void	poll(IThreadContext threadContext) Poll ALL bins periodically.
void	poll(IThreadContext threadContext, java.lang.String throttleGroupType) Poll periodically.
void	removeThrottleGroup(IThreadContext threadContext, java.lang.String throttleGroupType, java.lang.String throttleGroup) Remove a throttle group.

Methods inherited from class java.lang.Object

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

Field Detail

_rcsid

public static final java.lang.String _rcsid

See Also:

Constant Field Values

throttleGroupsHash

protected final java.util.Map<java.lang.String,Throttler.ThrottlingGroups> throttleGroupsHash

Throttle group hash table. Keyed by throttle group type, value is throttling groups

Constructor Detail

Throttler

public Throttler()

Create a throttler instance. Usually there will be one of these per connector type that needs throttling.

Method Detail

getThrottleGroups

public java.util.Set<java.lang.String> getThrottleGroups(IThreadContext threadContext,
                                                         java.lang.String throttleGroupType)
                                                  throws ManifoldCFException

Get all existing throttle groups for a throttle group type. The throttle group type typically describes a connector class, while the throttle group represents a namespace of bin names specific to that connector class.

Parameters:

throttleGroupType - is the throttle group type.

Returns:

the set of throttle groups for that group type.

Throws:

ManifoldCFException

removeThrottleGroup

public void removeThrottleGroup(IThreadContext threadContext,
                                java.lang.String throttleGroupType,
                                java.lang.String throttleGroup)
                         throws ManifoldCFException

Remove a throttle group.

Parameters:

throttleGroupType - is the throttle group type.

throttleGroup - is the throttle group.

Throws:

ManifoldCFException

createOrUpdateThrottleGroup

public void createOrUpdateThrottleGroup(IThreadContext threadContext,
                                        java.lang.String throttleGroupType,
                                        java.lang.String throttleGroup,
                                        IThrottleSpec throttleSpec)
                                 throws ManifoldCFException

Set or update throttle specification for a throttle group. This creates the throttle group if it does not yet exist.

Parameters:

throttleGroupType - is the throttle group type.

throttleGroup - is the throttle group.

throttleSpec - is the desired throttle specification object.

Throws:

ManifoldCFException

obtainConnectionThrottler

public IConnectionThrottler obtainConnectionThrottler(IThreadContext threadContext,
                                                      java.lang.String throttleGroupType,
                                                      java.lang.String throttleGroup,
                                                      java.lang.String[] binNames)
                                               throws ManifoldCFException

Construct connection throttler for connections with specific bin names. This object is meant to be embedded with a connection pool of similar objects, and used to gate the creation of new connections in that pool.

Parameters:

throttleGroupType - is the throttle group type.

throttleGroup - is the throttle group.

binNames - are the connection type bin names.

Returns:

the connection throttling object, or null if the pool is being shut down.

Throws:

ManifoldCFException

poll

public void poll(IThreadContext threadContext,
                 java.lang.String throttleGroupType)
          throws ManifoldCFException

Poll periodically.

Throws:

ManifoldCFException

poll

public void poll(IThreadContext threadContext)
          throws ManifoldCFException

Poll ALL bins periodically.

Throws:

ManifoldCFException

freeUnusedResources

public void freeUnusedResources(IThreadContext threadContext)
                         throws ManifoldCFException

Free unused resources.

Throws:

ManifoldCFException

destroy

public void destroy(IThreadContext threadContext)
             throws ManifoldCFException

Shut down all throttlers and deregister them.

Throws:

ManifoldCFException

buildThrottlingGroupName

protected static java.lang.String buildThrottlingGroupName(java.lang.String throttlingGroupType,
                                                           java.lang.String throttlingGroupName)