org.onosproject.ui

Class UiMessageHandler

java.lang.Object

org.onosproject.ui.UiMessageHandler

public abstract class UiMessageHandler
extends Object

Abstraction of an entity capable of processing JSON messages from the user interface client.

The message structure is:

 {
     "type": "event-type",
     "payload": {
         arbitrary JSON object structure
     }
 }
 

On initialization the handler will create and cache RequestHandler instances, each of which are bound to a particular event-type. On arrival of a new message, the event-type is determined, and the message dispatched to the corresponding RequestHandler's process method.

Constructor Summary

Constructors

Constructor and Description
UiMessageHandler()

Method Summary

Modifier and Type	Method and Description
protected com.fasterxml.jackson.databind.node.ArrayNode	arrayNode() Returns a freshly minted array node.
UiConnection	connection() Returns the user interface connection with which this handler was primed.
protected abstract Collection<RequestHandler>	createRequestHandlers() Subclasses must create and return the collection of request handlers for the message types they handle.
void	destroy() Destroys the message handler context.
org.onlab.osgi.ServiceDirectory	directory() Returns the user interface connection with which this handler was primed.
protected <T> T	get(Class<T> serviceClass) Returns implementation of the specified service class.
void	init(UiConnection connection, org.onlab.osgi.ServiceDirectory directory) Initializes the handler with the user interface connection and service directory context.
Set<String>	messageTypes() Returns the set of message types which this handler is capable of processing.
protected com.fasterxml.jackson.databind.node.ObjectNode	objectNode() Returns a freshly minted object node.
void	process(com.fasterxml.jackson.databind.node.ObjectNode message) Processes a JSON message from the user interface client.
protected void	sendMessage(com.fasterxml.jackson.databind.node.ObjectNode data) Sends the specified data to the client.

Methods inherited from class java.lang.Object

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

Constructor Detail

UiMessageHandler

public UiMessageHandler()

Method Detail

createRequestHandlers

protected abstract Collection<RequestHandler> createRequestHandlers()

Subclasses must create and return the collection of request handlers for the message types they handle.

Note that request handlers should be stateless. When we are destroyed, we will simply drop our references to them and allow them to be garbage collected.

Returns:

the message handler instances

messageTypes

public Set<String> messageTypes()

Returns the set of message types which this handler is capable of processing.

Returns:

set of message types

process

public void process(com.fasterxml.jackson.databind.node.ObjectNode message)

Processes a JSON message from the user interface client.

Parameters:

message - JSON message

init

public void init(UiConnection connection,
                 org.onlab.osgi.ServiceDirectory directory)

Initializes the handler with the user interface connection and service directory context.

Parameters:

connection - user interface connection

directory - service directory

destroy

public void destroy()

Destroys the message handler context.

connection

public UiConnection connection()

Returns the user interface connection with which this handler was primed.

Returns:

user interface connection

directory

public org.onlab.osgi.ServiceDirectory directory()

Returns the user interface connection with which this handler was primed.

Returns:

user interface connection

get

protected <T> T get(Class<T> serviceClass)

Returns implementation of the specified service class.

Type Parameters:

T - type of service

Parameters:

serviceClass - service class

Returns:

implementation class

Throws:

org.onlab.osgi.ServiceNotFoundException - if no implementation found

objectNode

protected com.fasterxml.jackson.databind.node.ObjectNode objectNode()

Returns a freshly minted object node.

Returns:

new object node

arrayNode

protected com.fasterxml.jackson.databind.node.ArrayNode arrayNode()

Returns a freshly minted array node.

Returns:

new array node

sendMessage

protected void sendMessage(com.fasterxml.jackson.databind.node.ObjectNode data)

Sends the specified data to the client. It is expected that the data is in the prescribed JSON format for events to the client.

Parameters:

data - data to be sent