com.caplin.motif.datasource

Class CachedAdapter

java.lang.Object

com.caplin.motif.datasource.CachedAdapter

Direct Known Subclasses:

FXRatesAdapter

public class CachedAdapter
extends Object

Provides a Single-Request, Single-Discard DataSource API for a DataProvider and simplifies the Publisher API. This class also handles multiple peer requests for the same subscription by maintaining a cache, which is useful for fail-over and redundancy scenarios.

Usage:

 CachedAdapter adapter = new CachedAdapter(dataSource);
 CachedPublisher publisher = adapter.createActivePublisher(new NamespacePrefix("/FX"), this, new FXSubjectParser());
 

Constructor Summary

Constructors

Constructor and Description
CachedAdapter(com.caplin.datasource.DataSource dataSource) Constructs a CachedAdapter to wrap requests made to the specified dataSource.

Method Summary

Modifier and Type	Method and Description
void	clearCache() Clears the cache of subscriptions and cached records.
CachedPublisher	createActivePublisher(com.caplin.datasource.namespace.Namespace namespace, CachedDataProvider<?> dataProvider, SubjectParser<?> parser) Creates an ActivePublisher that will publish messages on the specified Namespace. This method uses a subject parser which allows subjects to be parsed into meaningful request objects, for example the FXSubjectInfo.
CachedPublisher	createActivePublisher(com.caplin.datasource.namespace.Namespace namespace, CachedDataProvider<?> dataProvider, SubjectParser<?> parser, boolean sendDiscardAfterError) Creates an ActivePublisher that will publish messages on the specified Namespace. This method uses a subject parser which allows subjects to be parsed into meaningful request objects, for example the FXSubjectInfo
CachedPublisher	createActivePublisher(com.caplin.datasource.namespace.Namespace namespace, com.caplin.datasource.publisher.DataProvider dataProvider) Creates an ActivePublisher that will publish messages on the specified Namespace..
CachedPublisher	createActivePublisher(com.caplin.datasource.namespace.Namespace namespace, com.caplin.datasource.publisher.DataProvider dataProvider, boolean sendDiscardAfterError) Creates an ActivePublisher that will publish messages on the specified Namespace..

Methods inherited from class java.lang.Object

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

Constructor Detail

CachedAdapter

public CachedAdapter(com.caplin.datasource.DataSource dataSource)

Constructs a CachedAdapter to wrap requests made to the specified dataSource.

Parameters:

dataSource - The dataSource to wrap.

Method Detail

createActivePublisher

public CachedPublisher createActivePublisher(com.caplin.datasource.namespace.Namespace namespace,
                                             com.caplin.datasource.publisher.DataProvider dataProvider)

Creates an ActivePublisher that will publish messages on the specified Namespace.. Only use this method if you need to use a DataProvider instance, otherwise use createActivePublisher(com.caplin.datasource.namespace.Namespace, CachedDataProvider, SubjectParser) Also note that the Peer returned by RequestEvent.getPeer() and DiscardEvent.getPeer() will always be the first peer that made the request.

Parameters:

namespace - The namespace that the publisher will publish on.

dataProvider - The provider that will accept requests and discards.

Returns:

The CachedPublisher to use for publishing messages.

createActivePublisher

public CachedPublisher createActivePublisher(com.caplin.datasource.namespace.Namespace namespace,
                                             com.caplin.datasource.publisher.DataProvider dataProvider,
                                             boolean sendDiscardAfterError)

Creates an ActivePublisher that will publish messages on the specified Namespace.. Only use this method if you need to use a DataProvider instance, otherwise use createActivePublisher(com.caplin.datasource.namespace.Namespace, CachedDataProvider, SubjectParser) Also note that the Peer return by RequestEvent.getPeer() and DiscardEvent.getPeer() will always be the first peer that made the request.

Parameters:

namespace - The namespace that the publisher will publish on.

dataProvider - The provider that will accept requests and discards.

sendDiscardAfterError - If set to TRUE, your DataProvider will receive an immediate callback on the DataProvider.onDiscard(com.caplin.datasource.publisher.DiscardEvent) method after you publish a failure message by calling CachedPublisher.sendNotFound(String) or CachedPublisher.sendUnavailable(String). This can be useful if you want to use the same code path to clear a cache (for example) whether a subscription is ended by the client discarding it or the back end you are integrating with no longer providing the data.

Returns:

The CachedPublisher to use for publishing messages.

createActivePublisher

public CachedPublisher createActivePublisher(com.caplin.datasource.namespace.Namespace namespace,
                                             CachedDataProvider<?> dataProvider,
                                             SubjectParser<?> parser)

Creates an ActivePublisher that will publish messages on the specified Namespace. This method uses a subject parser which allows subjects to be parsed into meaningful request objects, for example the FXSubjectInfo.

Parameters:

namespace - The namespace that the publisher will publish on.

dataProvider - The provider that will accept requests and discards.

parser - The parser that will parse subject requests into a object representation of the request.

Returns:

The CachedPublisher to use for publishing messages.

createActivePublisher

public CachedPublisher createActivePublisher(com.caplin.datasource.namespace.Namespace namespace,
                                             CachedDataProvider<?> dataProvider,
                                             SubjectParser<?> parser,
                                             boolean sendDiscardAfterError)

Creates an ActivePublisher that will publish messages on the specified Namespace. This method uses a subject parser which allows subjects to be parsed into meaningful request objects, for example the FXSubjectInfo

Parameters:

namespace - The namespace that the publisher will publish on.

dataProvider - The provider that will accept requests and discards.

parser - The parser that will parse subject requests into a object representation of the request.

sendDiscardAfterError - If set to TRUE, your DataProvider will receive an immediate callback on the CachedDataProvider.onDiscard(SubjectInfo) method after you publish a failure message by calling CachedPublisher.sendNotFound(String) or CachedPublisher.sendUnavailable(String). This can be useful if you want to use the same code path to clear a cache (for example) whether a subscription is ended by the client discarding it or the back end you are integrating with no longer providing the data.

Returns:

The CachedPublisher to use for publishing messages.

clearCache

public void clearCache()

Clears the cache of subscriptions and cached records. Only invoke this method when a peer down message has been received.