org.arl.fjage.observer

Class ObserverFilter

java.lang.Object

org.arl.fjage.observer.ObserverFilter

All Implemented Interfaces:

MessageFilter

public class ObserverFilter
extends java.lang.Object
implements MessageFilter

Filter used by Observer to decide which messages to publish to the web interface.

The filter is applied in the container, before serialization, and so a message rejected by it is never seen by any web client. It is deliberately an exclusion-oriented filter: it is meant to silence traffic that is known to be uninteresting, so that the cost of serializing it is never paid. Deciding which of the remaining messages to display is left to the web interface, which can do so retrospectively.

Regular expressions are matched using find() semantics, i.e., a substring match is sufficient. Anchor with ^ and $ for an exact match. A null or empty expression is ignored. An invalid expression is logged and ignored, so that a typo in the web interface cannot break observation.

The public fields are deliberately simple, so that this class can be populated directly from the JSON sent by the web interface.

Field Summary

Fields

Modifier and Type	Field and Description
java.lang.String	clazz Regex that the message class name must match, null to allow all.
java.lang.String	excludeClazz Regex that the message class name must not match, null to allow all.
java.util.Set<java.lang.String>	excludeEndpoints Endpoint names whose messages are to be dropped.

Constructor Summary

Constructors

Constructor and Description
ObserverFilter() Creates a filter that publishes all messages.

Method Summary

Modifier and Type	Method and Description
ObserverFilter	compile() Compiles the regular expressions.
ObserverFilter	exclude(java.util.Collection<java.lang.String> endpoints) Sets the endpoints whose messages are to be dropped.
ObserverFilter	exclude(java.lang.String... endpoints) Sets the endpoints whose messages are to be dropped.
boolean	matches(Message m) Returns true if a message matches the criteria, false otherwise.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

clazz

public java.lang.String clazz

Regex that the message class name must match, null to allow all.

excludeClazz

public java.lang.String excludeClazz

Regex that the message class name must not match, null to allow all.

excludeEndpoints

public java.util.Set<java.lang.String> excludeEndpoints

Endpoint names whose messages are to be dropped. A message is dropped if either its sender or its recipient is named here. Topics are named with their # prefix, as they are encoded on the wire.

Constructor Detail

ObserverFilter

public ObserverFilter()

Creates a filter that publishes all messages.

Method Detail

compile

public ObserverFilter compile()

Compiles the regular expressions. Must be called after the fields are populated, and before the filter is used.

Returns:

this filter, for chaining.

exclude

public ObserverFilter exclude(java.lang.String... endpoints)

Sets the endpoints whose messages are to be dropped.

Parameters:

endpoints - endpoint names, null or empty to drop nothing.

Returns:

this filter, for chaining.

exclude

public ObserverFilter exclude(java.util.Collection<java.lang.String> endpoints)

Sets the endpoints whose messages are to be dropped.

Parameters:

endpoints - endpoint names, null or empty to drop nothing.

Returns:

this filter, for chaining.

matches

public boolean matches(Message m)

Description copied from interface: MessageFilter

Returns true if a message matches the criteria, false otherwise. An implementing class must override this method to provide the appropriate selection criteria for the message filter.

Specified by:

matches in interface MessageFilter

Parameters:

m - message to check.

Returns:

true if the message matches the criteria, false otherwise.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object