Package org.springframework.integration.selector

Class MetadataStoreSelector

java.lang.Object

org.springframework.integration.selector.MetadataStoreSelector

All Implemented Interfaces:

GenericSelector<Message<?>>, MessageSelector

public class MetadataStoreSelector
extends Object
implements MessageSelector

The MessageSelector implementation using a ConcurrentMetadataStore and MessageProcessor.

The accept(org.springframework.messaging.Message<?>) method extracts metadataKey from the provided message using MessageProcessor and uses the timestamp header as the value (hex) by default. The valueStrategy can be provided to override the default behaviour.

The successful result of the accept(org.springframework.messaging.Message<?>) method is based on the ConcurrentMetadataStore.putIfAbsent(java.lang.String, java.lang.String) return value. true is returned if putIfAbsent returns null. And, at the same time, it means that the value has been placed in the MetadataStore. Otherwise the messages isn't accepted because there is already a value in the MetadataStore associated with the key.

This MessageSelector is useful for an Idempotent Receiver implementation.

It can be used in a MessageFilter or IdempotentReceiverInterceptor.

Since:

4.1

Author:

Artem Bilan, Gary Russell

Constructor Summary

Constructors

Constructor	Description
MetadataStoreSelector(MessageProcessor<String> keyStrategy)
MetadataStoreSelector(MessageProcessor<String> keyStrategy, MessageProcessor<String> valueStrategy)
MetadataStoreSelector(MessageProcessor<String> keyStrategy, MessageProcessor<String> valueStrategy, ConcurrentMetadataStore metadataStore)
MetadataStoreSelector(MessageProcessor<String> keyStrategy, ConcurrentMetadataStore metadataStore)

Method Summary

Modifier and Type	Method	Description
boolean	accept(Message<?> message)
MetadataStoreSelector	compareValues(BiPredicate<String,String> compareValues)	Fluent version of setCompareValues(BiPredicate).
void	setCompareValues(BiPredicate<String,String> compareValues)	Set a BiPredicate to compare old and new values in the metadata store for the key.

Methods inherited from class java.lang.Object

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

Constructor Details

MetadataStoreSelector

public MetadataStoreSelector(MessageProcessor<String> keyStrategy)

MetadataStoreSelector

public MetadataStoreSelector(MessageProcessor<String> keyStrategy, MessageProcessor<String> valueStrategy)

MetadataStoreSelector

public MetadataStoreSelector(MessageProcessor<String> keyStrategy, ConcurrentMetadataStore metadataStore)

MetadataStoreSelector

public MetadataStoreSelector(MessageProcessor<String> keyStrategy, MessageProcessor<String> valueStrategy, ConcurrentMetadataStore metadataStore)

Method Details

setCompareValues

public void setCompareValues(@Nullable BiPredicate<String,String> compareValues)

Set a BiPredicate to compare old and new values in the metadata store for the key. The first parameter is the old value; return true if we should accept this message and replace the old value with the new value.

Parameters:

compareValues - the BiPredicate.

Since:

5.3

compareValues

public MetadataStoreSelector compareValues(@Nullable BiPredicate<String,String> compareValues)

Fluent version of setCompareValues(BiPredicate).

Parameters:

compareValues - the BiPredicate.

Returns:

this.

accept

public boolean accept(Message<?> message)

Specified by:

accept in interface GenericSelector<Message<?>>

Specified by:

accept in interface MessageSelector