Package org.flasby.bus

Class PageBus

java.lang.Object

org.flasby.bus.PageBus

public class PageBus
extends Object

delivers publications to subscribers using a dotted addressing scheme. Delivery is made in a separate thread so is asynchronous. Publications can be overtaken by later ones with the same subject if the earlier publication was marked as VOLATILE. This can be used to prevent out of date messages from being delivered.

A typical application of this would be a price tick. The price has changed so there is often no point in delivering the out of date price.

In flight messages are not cancelled if a replacement arrives, only publications still waiting to be delivered. The new publication is always added to the end of the delivery queue.

Author:

Steve Flasby Jul 24, 2012

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	PageBus.MessageVolatility
static interface	PageBus.Subscriber
static final class	PageBus.Subscription

Field Summary

Fields

Modifier and Type	Field	Description
static final String	STARTING
static final String	STOPPING

Constructor Summary

Constructors

Constructor	Description
PageBus()

Method Summary

Modifier and Type	Method	Description
static PageBus	getGlobalInstance()
void	publish(String subject, Object publication, PageBus.MessageVolatility isVolatile)	publish something on the bus.
PageBus.Subscription	subscribe(String address, PageBus.Subscriber delivery)
void	unsubscribe(PageBus.Subscription subscription)

Methods inherited from class java.lang.Object

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

Field Details

STARTING

public static final String STARTING

See Also:

• Constant Field Values

STOPPING

public static final String STOPPING

See Also:

• Constant Field Values

Constructor Details

PageBus

public PageBus()

Method Details

getGlobalInstance

public static PageBus getGlobalInstance()

publish

public void publish(String subject,
 Object publication,
 PageBus.MessageVolatility isVolatile)

publish something on the bus.

Parameters:

subject - the subject of the publication structured using a dotted notation.

publication - the thing being published.

isVolatile - if VOLATILE then this publication can be deleted from the delivery queue if another publication with an identical subject is published which is also VOLATILE.

subscribe

public PageBus.Subscription subscribe(String address,
 PageBus.Subscriber delivery)

unsubscribe

public void unsubscribe(PageBus.Subscription subscription)