Package org.appng.api.messaging

Class Messaging

java.lang.Object

org.appng.api.messaging.Messaging

public class Messaging
extends Object

A utility class offering static helper methods to create and retrieve a Sender and to shutdown Senders and Receivers.

Author:

Matthias Müller

See Also:

Sender, Receiver

Field Summary

Fields

Modifier and Type	Field	Description
static String	APPNG_NODE_ID	Name of a system property used to identify the node

Constructor Summary

Constructors

Constructor	Description
Messaging()

Method Summary

Modifier and Type	Method	Description
static Sender	createMessageSender(Environment env, ExecutorService executor)	Creates and returns a new Sender and a corresponding Receiver.
static Sender	createMessageSender(Environment env, ExecutorService executor, String nodeId, EventHandler<? extends Event> defaultHandler, Iterable<EventHandler<? extends Event>> handlers)	Creates and returns a new Sender and a corresponding Receiver.
static Sender	getMessageSender(Environment env)	Retrieves the previously created Sender from the Environment.
static String	getNodeId(Environment env)	Determines the node id for this node.
protected static Properties	getPlatformConfig(Environment env)
static boolean	isEnabled(Environment env)
static void	shutdown(Environment env)	Shuts down the messaging system, i.e.

Methods inherited from class java.lang.Object

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

Field Detail

APPNG_NODE_ID

public static final String APPNG_NODE_ID

Name of a system property used to identify the node

See Also:

Constant Field Values

Constructor Detail

Messaging

public Messaging()

Method Detail

getMessageSender

public static Sender getMessageSender(Environment env)

Retrieves the previously created Sender from the Environment.

Parameters:

env - the Environment to use

Returns:

the Sender, if available

See Also:

createMessageSender(Environment, ExecutorService), createMessageSender(Environment, ExecutorService, String, EventHandler, Iterable)

createMessageSender

public static Sender createMessageSender(Environment env,
                                         ExecutorService executor)

Creates and returns a new Sender and a corresponding Receiver. The class name for the receiver is taken from the platform property "messagingReceiver". Uses the system property "appng.node.id" to retrieve the node id for the Serializer. If this property is absent, the local host name is used and the property is set.

Parameters:

env - the Environment to use

executor - the ExecutorService to run the Receiver with

Returns:

• the Sender (if the platform property "messagingEnabled" is true
• null if messaging is disabled or an error occurred while creating the sender

getNodeId

public static String getNodeId(Environment env)

Determines the node id for this node. If the system property "appng.node.id" is set, this value is used. Otherwise, the local host name is used (from java.net.InetAddress.getLocalHost().getHostName()}).

Parameters:

env - the Environment to use

Returns:

the node id for this node

getPlatformConfig

protected static Properties getPlatformConfig(Environment env)

createMessageSender

public static Sender createMessageSender(Environment env,
                                         ExecutorService executor,
                                         String nodeId,
                                         EventHandler<? extends Event> defaultHandler,
                                         Iterable<EventHandler<? extends Event>> handlers)

Creates and returns a new Sender and a corresponding Receiver. The class name for the receiver is taken from the platform property "messagingReceiver".

Parameters:

env - the Environment to use

executor - the ExecutorService to run the Receiver with

nodeId - the node id for the Serializer

defaultHandler - the default EventHandler for the Receiver (may be null)

handlers - a list of EventHandlers to be registered at the Receiver

Returns:

• the Sender (if the platform property "messagingEnabled" is true
• null if messaging is disabled or an error occurred while creating the sender

isEnabled

public static boolean isEnabled(Environment env)

shutdown

public static void shutdown(Environment env)

Shuts down the messaging system, i.e. calls Closeable.close() for the Sender and the Receiver (in case the latter do implement Closeable)

Parameters:

env - then Environment to use