org.springframework.batch.repeat.policy
Class CountingCompletionPolicy

java.lang.Object
  org.springframework.batch.repeat.policy.CompletionPolicySupport
      org.springframework.batch.repeat.policy.DefaultResultCompletionPolicy
          org.springframework.batch.repeat.policy.CountingCompletionPolicy

All Implemented Interfaces:

CompletionPolicy

public abstract class CountingCompletionPolicy
extends DefaultResultCompletionPolicy

Abstract base class for policies that need to count the number of occurrences of some event (e.g. an exception type in the context), and terminate based on a limit for the counter. The value of the counter can be stored between batches in a nested context, so that the termination decision is based on the aggregate of a number of sibling batches.

Author:

Dave Syer

Nested Class Summary

protected class

CountingCompletionPolicy.CountingBatchContext

Field Summary

static String

COUNT Session key for global counter.

Constructor Summary

CountingCompletionPolicy()

Method Summary

protected int	doUpdate(RepeatContext context) Extension point for subclasses.
protected abstract int	getCount(RepeatContext context) Extension point for subclasses.
boolean	isComplete(RepeatContext context) Always false.
void	setMaxCount(int maxCount) Setter for maximum value of count before termination.
void	setUseParent(boolean useParent) Flag to indicate whether the count is at the level of the parent context, or just local to the context.
RepeatContext	start(RepeatContext parent) Build a new RepeatContextSupport and return it.
void	update(RepeatContext context) Increment the context so the counter is up to date.

Methods inherited from class org.springframework.batch.repeat.policy.DefaultResultCompletionPolicy

isComplete

Methods inherited from class java.lang.Object

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

Field Detail

COUNT

public static final String COUNT

Session key for global counter.

Constructor Detail

CountingCompletionPolicy

public CountingCompletionPolicy()

Method Detail

setUseParent

public void setUseParent(boolean useParent)

Flag to indicate whether the count is at the level of the parent context, or just local to the context. If true then the count is aggregated among siblings in a nested batch.

Parameters:

useParent - whether to use the parent context to cache the total count. Default value is false.

setMaxCount

public void setMaxCount(int maxCount)

Setter for maximum value of count before termination.

Parameters:

maxCount - the maximum number of counts before termination. Default 0 so termination is immediate.

getCount

protected abstract int getCount(RepeatContext context)

Extension point for subclasses. Obtain the value of the count in the current context. Subclasses can count the number of attempts or violations and store the result in their context. This policy base class will take care of the termination contract and aggregating at the level of the session if required.

Parameters:

context - the current context, specific to the subclass.

Returns:

the value of the counter in the context.

doUpdate

protected int doUpdate(RepeatContext context)

Extension point for subclasses. Inspect the context and update the state of a counter in whatever way is appropriate. This will be added to the session-level counter if setUseParent(boolean) is true.

Parameters:

context - the current context.

Returns:

the change in the value of the counter (default 0).

isComplete

public final boolean isComplete(RepeatContext context)

Description copied from class: DefaultResultCompletionPolicy

Always false.

Specified by:

isComplete in interface CompletionPolicy

Overrides:

isComplete in class DefaultResultCompletionPolicy

Parameters:

context - the current batch context.

Returns:

true if the batch should terminate.

See Also:

CompletionPolicy.isComplete(org.springframework.batch.repeat.RepeatContext)

start

public RepeatContext start(RepeatContext parent)

Description copied from class: CompletionPolicySupport

Build a new RepeatContextSupport and return it.

Specified by:

start in interface CompletionPolicy

Overrides:

start in class CompletionPolicySupport

Parameters:

parent - the current context if one is already in progress.

Returns:

a context object that can be used by the implementation to store internal state for a batch.

See Also:

CompletionPolicy.start(RepeatContext)

update

public final void update(RepeatContext context)

Description copied from class: CompletionPolicySupport

Increment the context so the counter is up to date. Do nothing else.

Specified by:

update in interface CompletionPolicy

Overrides:

update in class CompletionPolicySupport

Parameters:

context - the value returned by start.

See Also:

CompletionPolicy.update(org.springframework.batch.repeat.RepeatContext)