Package hudson.slaves

Class RetentionStrategy<T extends Computer>

java.lang.Object

hudson.slaves.RetentionStrategy<T>

All Implemented Interfaces:

ExtensionPoint, Describable<RetentionStrategy<?>>

Direct Known Subclasses:

CloudRetentionStrategy, CloudSlaveRetentionStrategy, RetentionStrategy.Always, RetentionStrategy.Demand, SimpleScheduledRetentionStrategy

public abstract class RetentionStrategy<T extends Computer>
extends Object
implements Describable<RetentionStrategy<?>>, ExtensionPoint

Controls when to take Computer offline, bring it back online, or even to destroy it.

Author:

Stephen Connolly, Kohsuke Kawaguchi

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	RetentionStrategy.Always	RetentionStrategy that tries to keep the node online all the time.
static class	RetentionStrategy.Demand	RetentionStrategy that tries to keep the node offline when not in use.

Nested classes/interfaces inherited from interface hudson.ExtensionPoint

ExtensionPoint.LegacyInstancesAreScopedToHudson

Field Summary

Fields

Modifier and Type	Field	Description
static final RetentionStrategy.Always	INSTANCE	Convenient singleton instance, since this RetentionStrategy is stateless.
static final DescriptorList<RetentionStrategy<?>>	LIST	Deprecated. as of 1.286 Use all() for read access, and Extension for registration.
static final RetentionStrategy<Computer>	NOOP	Dummy instance that doesn't do any attempt to retention.

Constructor Summary

Constructors

Constructor	Description
RetentionStrategy()

Method Summary

Modifier and Type	Method	Description
static DescriptorExtensionList<RetentionStrategy<?>,Descriptor<RetentionStrategy<?>>>	all()	Returns all the registered RetentionStrategy descriptors.
abstract long	check(T c)	This method will be called periodically to allow this strategy to decide what to do with its owning agent.
boolean	isAcceptingTasks(T c)	Returns true if the computer is accepting tasks.
boolean	isManualLaunchAllowed(T c)	This method is called to determine whether manual launching of the agent is allowed right now.
void	start(T c)	Called when a new Computer object is introduced (such as when Hudson started, or when a new agent is added).

Methods inherited from class java.lang.Object

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

Methods inherited from interface hudson.model.Describable

getDescriptor

Field Details

LIST

@Deprecated
public static final DescriptorList<RetentionStrategy<?>> LIST

Deprecated.

as of 1.286 Use all() for read access, and Extension for registration.

All registered RetentionStrategy implementations.

NOOP

public static final RetentionStrategy<Computer> NOOP

Dummy instance that doesn't do any attempt to retention.

INSTANCE

public static final RetentionStrategy.Always INSTANCE

Convenient singleton instance, since this RetentionStrategy is stateless.

Constructor Details

RetentionStrategy

public RetentionStrategy()

Method Details

check

public abstract long check(@NonNull
 T c)

This method will be called periodically to allow this strategy to decide what to do with its owning agent.

Parameters:

c - Computer for which this strategy is assigned. This computer may be online or offline. This object also exposes a bunch of properties that the callee can use to decide what action to take.

Returns:

The number of minutes after which the strategy would like to be checked again. The strategy may be rechecked earlier or later than this!

isManualLaunchAllowed

public boolean isManualLaunchAllowed(T c)

This method is called to determine whether manual launching of the agent is allowed right now.

Parameters:

c - Computer for which this strategy is assigned. This computer may be online or offline. This object also exposes a bunch of properties that the callee can use to decide if manual launching is allowed.

Returns:

true if manual launching of the agent is allowed right now.

isAcceptingTasks

public boolean isAcceptingTasks(T c)

Returns true if the computer is accepting tasks. Needed to allow retention strategies programmatic suspension of task scheduling that in preparation for going offline. Called by Computer.isAcceptingTasks()

Parameters:

c - the computer.

Returns:

true if the computer is accepting tasks

Since:

1.586

See Also:

• Computer.isAcceptingTasks()

start

public void start(@NonNull
 T c)

Called when a new Computer object is introduced (such as when Hudson started, or when a new agent is added).

The default implementation of this method delegates to check(Computer), but this allows RetentionStrategy to distinguish the first time invocation from the rest.

Parameters:

c - Computer instance

Since:

1.275

all

public static DescriptorExtensionList<RetentionStrategy<?>,Descriptor<RetentionStrategy<?>>> all()

Returns all the registered RetentionStrategy descriptors.