com.goldencode.p2j.report.server

Class ReportProtocol

java.lang.Object

com.goldencode.p2j.report.server.ReportProtocol

@WebSocket
public class ReportProtocol
extends java.lang.Object

A protocol for communications between the report server and a web client over a web socket. Parameters and return data are marshalled and unmarshalled using Jackson. API calls are dispatched using reflection, and parameters and returned objects are marshalled/unmarshalled according to the method signatures of the API methods invoked. If an exception is thrown during the processing of an API request, that exception is marshalled and returned as the payload of a response message.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private class	ReportProtocol.ResponseWriter Writer to which a JSON generator streams JSON output, and which writes it to the remote endpoint as it is generated.
private class	ReportProtocol.Services API services that are specific to the protocol and user session.

Field Summary

Fields

Modifier and Type	Field and Description
private static int	JSON_MAX_CHUNK Maximum JSON chunk length sent as a response
private static ConversionStatus	LOG Logger.
static int	MSG_BASE Base value for message types
private static java.util.concurrent.atomic.AtomicLong	nextSessionId Next available session ID
private static java.util.Map<java.lang.Integer,java.lang.reflect.Method>	requestApi Map of API types to API handler methods
private static java.util.Set<java.lang.Class<?>>	requestApiClasses Set of classes which contain API handler methods
private java.util.Map<java.lang.Class<?>,java.lang.Object>	requestWorkers Map of API handler classes to instances of these classes which perform API work
private org.eclipse.jetty.websocket.api.Session	session Active web socket session
private long	sessionId Current session ID
private User	user Logged on user (null if no user is currently logged in)

Constructor Summary

Constructors

Constructor and Description
ReportProtocol() Default constructor.

Method Summary

Modifier and Type	Method and Description
private void	cleanup() Clean up after a session ends.
private void	generateJsonResponse(com.fasterxml.jackson.core.JsonGenerator gen, int msgId, int msgType, boolean success, java.lang.Object payload) Generate a JSON message response which includes a message header and payload.
void	onClose(int statusCode, java.lang.String reason) This method is called when the connection is closed.
void	onConnect(org.eclipse.jetty.websocket.api.Session session) This method is called when the remote peer open a web socket connection.
void	onError(org.eclipse.jetty.websocket.api.Session session, java.lang.Throwable error) This method is called on communication errors.
void	onMessage(byte[] message, int offset, int length) This method is called when a binary message is received.
void	onMessage(java.lang.String message) This method is called when a text message is received.
private void	processIncoming(java.lang.String message) Process an incoming JSON message string for a request API.
static void	registerRequestApi(java.lang.Class<?> apiClass) Register an API handler class.
private static void	registerRequestApi(java.lang.Class<?> apiClass, boolean autoInstantiate) Register an API handler class.

Methods inherited from class java.lang.Object

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

Field Detail

MSG_BASE

public static final int MSG_BASE

Base value for message types

See Also:

Constant Field Values

LOG

private static final ConversionStatus LOG

Logger.

JSON_MAX_CHUNK

private static final int JSON_MAX_CHUNK

Maximum JSON chunk length sent as a response

See Also:

Constant Field Values

requestApi

private static final java.util.Map<java.lang.Integer,java.lang.reflect.Method> requestApi

Map of API types to API handler methods

requestApiClasses

private static final java.util.Set<java.lang.Class<?>> requestApiClasses

Set of classes which contain API handler methods

nextSessionId

private static java.util.concurrent.atomic.AtomicLong nextSessionId

Next available session ID

requestWorkers

private final java.util.Map<java.lang.Class<?>,java.lang.Object> requestWorkers

Map of API handler classes to instances of these classes which perform API work

session

private org.eclipse.jetty.websocket.api.Session session

Active web socket session

sessionId

private long sessionId

Current session ID

user

private User user

Logged on user (null if no user is currently logged in)

Constructor Detail

ReportProtocol

public ReportProtocol()

Default constructor.

Method Detail

registerRequestApi

public static void registerRequestApi(java.lang.Class<?> apiClass)

Register an API handler class. All methods marked with the WebApi annotation will be registered as request API handler methods.

Parameters:

apiClass - A class which contains one or more request API handler methods.

registerRequestApi

private static void registerRequestApi(java.lang.Class<?> apiClass,
                                       boolean autoInstantiate)

Register an API handler class. All methods marked with the WebApi annotation will be registered as request API handler methods.

Parameters:

apiClass - A class which contains one or more request API handler methods.

autoInstantiate - true to automatically instantiate the API class using reflection when the web socket connects; false if reflection should not be used (only relevant for the Services inner class).

onConnect

@OnWebSocketConnect
public void onConnect(org.eclipse.jetty.websocket.api.Session session)

This method is called when the remote peer open a web socket connection.

Parameters:

session - An active link of communications with a Remote WebSocket Endpoint.

onClose

@OnWebSocketClose
public void onClose(int statusCode,
                                      java.lang.String reason)

This method is called when the connection is closed.

Parameters:

statusCode - The status integer code.

reason - A string representing the reason.

onMessage

@OnWebSocketMessage
public void onMessage(java.lang.String message)

This method is called when a text message is received.

Parameters:

message - The text message.

onMessage

@OnWebSocketMessage
public void onMessage(byte[] message,
                                          int offset,
                                          int length)

This method is called when a binary message is received.

Parameters:

message - Message content as an byte array.

offset - Message offset.

length - Message size.

onError

@OnWebSocketError
public void onError(org.eclipse.jetty.websocket.api.Session session,
                                      java.lang.Throwable error)

This method is called on communication errors.

Parameters:

session - An active link of communications with a Remote WebSocket Endpoint.

error - A Throwable instance representing the error condition.

processIncoming

private void processIncoming(java.lang.String message)

Process an incoming JSON message string for a request API. This involves:

1. Deserializing the JSON message, which consists of a message header and optional payload. If present, the payload will consist of an array of serialized objects and/or primitives.
2. Invoking the appropriate API handler method.
3. Serializing the value (if any) returned by the API worker method into a response JSON string message.
4. Sending the response message to the remote side of the web socket.

Parameters:

message - Incoming JSON message.

generateJsonResponse

private void generateJsonResponse(com.fasterxml.jackson.core.JsonGenerator gen,
                                  int msgId,
                                  int msgType,
                                  boolean success,
                                  java.lang.Object payload)
                           throws java.io.IOException

Generate a JSON message response which includes a message header and payload.

Parameters:

gen - Jackson JSON generator.

msgId - Message identifier sent with message request.

msgType - Type of message request to which this is the response.

success - True if the API was successfully executed; false if there was an error.

payload - Response payload, which will be the normal payload if the API was successful, or a Throwable if an exception occurred.

Throws:

java.io.IOException - if there is an error serializing the response to JSON.

cleanup

private void cleanup()

Clean up after a session ends.