org.astrogrid.samp.client

Class AbstractMessageHandler

java.lang.Object

org.astrogrid.samp.client.AbstractMessageHandler

All Implemented Interfaces:

MessageHandler

public abstract class AbstractMessageHandler
extends Object
implements MessageHandler

Partial implementation of MessageHandler interface which helps to ensure correct client behaviour. Concrete subclasses just need to specify the MTypes they subscribe to and implement the processCall(org.astrogrid.samp.client.HubConnection, java.lang.String, org.astrogrid.samp.Message) method.

Since:

16 Jul 2008

Author:

Mark Taylor

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractMessageHandler(Map subscriptions) Constructor using a given subscriptions map.
protected	AbstractMessageHandler(String mtype) Constructor using a single subscribed MType.
protected	AbstractMessageHandler(String[] mtypes) Constructor using a given list of subscribed MTypes.

Method Summary

Modifier and Type	Method and Description
protected Response	createResponse(Map processOutput) Invoked by receiveCall to create a success response from the result of calling processCall.
Map	getSubscriptions() Returns a Subscriptions map corresponding to the messages handled by this object.
abstract Map	processCall(HubConnection connection, String senderId, Message message) Implements message processing.
void	receiveCall(HubConnection connection, String senderId, String msgId, Message message) Calls processCall(org.astrogrid.samp.client.HubConnection, java.lang.String, org.astrogrid.samp.Message), generates a response from the result using createResponse(java.util.Map), and sends the resulting response as a reply to the hub.
void	receiveNotification(HubConnection connection, String senderId, Message message) Calls processCall(org.astrogrid.samp.client.HubConnection, java.lang.String, org.astrogrid.samp.Message) and discards the result.
void	setSubscriptions(Map subscriptions) Sets the subscriptions map.

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractMessageHandler

protected AbstractMessageHandler(Map subscriptions)

Constructor using a given subscriptions map.

Parameters:

subscriptions - Subscriptions-like map defining which MTypes this handler can process

AbstractMessageHandler

protected AbstractMessageHandler(String[] mtypes)

Constructor using a given list of subscribed MTypes.

Parameters:

mtypes - list of MTypes which this handler can process

AbstractMessageHandler

protected AbstractMessageHandler(String mtype)

Constructor using a single subscribed MType.

Parameters:

mtype - single MType which this handler can process

Method Detail

processCall

public abstract Map processCall(HubConnection connection,
                                String senderId,
                                Message message)
                         throws Exception

Implements message processing. Implementations should normally return a map which contains the samp.result part of the call response, that is the MType-specific return value name->value map. As a special case, returning null is equivalent to returning an empty map. However, if createResponse(java.util.Map) is overridden, the return value semantics may be different.

Parameters:

connection - hub connection

senderId - public ID of sender client

message - message with MType this handler is subscribed to

Returns:

result of handling this message; exact semantics determined by createResponse implementation

Throws:

Exception

createResponse

protected Response createResponse(Map processOutput)

Invoked by receiveCall to create a success response from the result of calling processCall.

The default implementation calls Response.createSuccessResponse(java.util.Map)(processOutput), first transforming a null value to an empty map for convenience. However, it may be overridden for more flexibility (for instance in order to return non-OK responses).

Parameters:

processOutput - a Map returned by processCall

setSubscriptions

public void setSubscriptions(Map subscriptions)

Sets the subscriptions map. Usually this is called by the constructor, but it may be reset manually.

Parameters:

subscriptions - Subscriptions-like map defining which MTypes this handler can process

getSubscriptions

public Map getSubscriptions()

Description copied from interface: MessageHandler

Returns a Subscriptions map corresponding to the messages handled by this object. Only messages with MTypes which match the keys of this map will be passed to this object.

Specified by:

getSubscriptions in interface MessageHandler

Returns:

Subscriptions-like map

receiveNotification

public void receiveNotification(HubConnection connection,
                                String senderId,
                                Message message)

Calls processCall(org.astrogrid.samp.client.HubConnection, java.lang.String, org.astrogrid.samp.Message) and discards the result.

Specified by:

receiveNotification in interface MessageHandler

Parameters:

connection - hub connection

senderId - public ID of client which sent the message

message - message

receiveCall

public void receiveCall(HubConnection connection,
                        String senderId,
                        String msgId,
                        Message message)
                 throws SampException

Calls processCall(org.astrogrid.samp.client.HubConnection, java.lang.String, org.astrogrid.samp.Message), generates a response from the result using createResponse(java.util.Map), and sends the resulting response as a reply to the hub. In case of an exception, a suitable error response is sent instead.

Specified by:

receiveCall in interface MessageHandler

Parameters:

connection - hub connection

senderId - public ID of client which sent the message

msgId - message ID

message - message

Throws:

SampException