org.xsocket.connection
Class HandlerChain

java.lang.Object
  org.xsocket.connection.HandlerChain

All Implemented Interfaces:

IConnectHandler, IConnectionTimeoutHandler, IDataHandler, IDisconnectHandler, IHandler, IIdleTimeoutHandler, ILifeCycle

public final class HandlerChain
extends Object
implements IHandler, IConnectHandler, IDataHandler, IDisconnectHandler, IConnectionTimeoutHandler, IIdleTimeoutHandler, ILifeCycle

Implements a handler chain. Each handler of the chain will be called (in the registering order), until one handler signal by the return value true, that the event has been handled. In this case the remaining handlers will not be called.

Nested chains is not supported yet
E.g.

   ...
   HandlerChain tcpBasedSpamfilter = new HandlerChain();
   tcpBasedSpamfilter.addLast(new BlackIPFilter()); 
   tcpBasedSpamfilter.addLast(new FirstConnectRefuseFilter());
   
   HandlerChain mainChain = new HandlerChain();
   mainChain.addLast(tcpBasedSpamfilter);
   mainChain.addLast(new SmtpProtocolHandler());
   
   IMultithreadedServer smtpServer = new MultithreadedServer(port, mainChain);
   StreamUtils.start(server);
   ...
   
 

Author:

grro@xsocket.org

Field Summary

Fields inherited from interface org.xsocket.connection.IHandler

DEFAULT_EXECUTION_MODE

Constructor Summary

HandlerChain()
constructor

HandlerChain(List<IHandler> handlers)
constructor

Method Summary

void	addLast(IHandler handler) add a handler to the end og the chain
boolean	onConnect(INonBlockingConnection connection) handles a new incoming connection
boolean	onConnectionTimeout(INonBlockingConnection connection) handles the connection timeout.
boolean	onData(INonBlockingConnection connection) processes the incoming data based on the given connection.
void	onDestroy() notifies that the entity will be destroyed
boolean	onDisconnect(INonBlockingConnection connection) handles disconnecting of a connection
boolean	onIdleTimeout(INonBlockingConnection connection) handles the idle timeout.
void	onInit() notifies that the entity has been loaded and initialized

Methods inherited from class java.lang.Object

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

Constructor Detail

HandlerChain

public HandlerChain()

constructor

HandlerChain

public HandlerChain(List<IHandler> handlers)

constructor

Parameters:

handlers - the initial handlers

Method Detail

onInit

public void onInit()

Description copied from interface: ILifeCycle

notifies that the entity has been loaded and initialized

Specified by:

onInit in interface ILifeCycle

onDestroy

public void onDestroy()
               throws IOException

Description copied from interface: ILifeCycle

notifies that the entity will be destroyed

Specified by:

onDestroy in interface ILifeCycle

Throws:

IOException - if an exception occurs. The exception will be (logged and) swallowed

addLast

public void addLast(IHandler handler)

add a handler to the end og the chain

Parameters:

handler - the handler to add

onConnect

public boolean onConnect(INonBlockingConnection connection)
                  throws IOException,
                         BufferUnderflowException,
                         MaxReadSizeExceededException

handles a new incoming connection

Specified by:

onConnect in interface IConnectHandler

Returns:

true for positive result of handling, false for negative result of handling

Throws:

IOException - if some other I/O error occurs. Throwing this exception causes that the underlying connection will be closed.

MaxReadSizeExceededException - if the max read size has been reached (e.g. by calling method IDataSource.readStringByDelimiter(String, int)). Throwing this exception causes that the underlying connection will be closed.

BufferUnderflowException - if more incoming data is required to process (e.g. delimiter hasn't yet received -> readByDelimiter methods or size of the available, received data is smaller than the required size -> readByLength). The BufferUnderflowException will be swallowed by the framework

onData

public boolean onData(INonBlockingConnection connection)
               throws IOException

processes the incoming data based on the given connection.

Please note, that the onData call back method can also be called for if an connection will be closed. In this case the isOpen call within the onData Method will return false. Reading of already received data will not fail. To detect if a connection has been closed the callback method onDisconnect should be implemented. The correct call back order will be managed by the xSocket.

Specified by:

onData in interface IDataHandler

Parameters:

connection - the underlying connection

Returns:

true for positive result of handling, false for negative result of handling. The return value will be used by the HandlerChain to interrupted the chaining (if result is true)

Throws:

IOException - If some other I/O error occurs. Throwing this exception causes that the underlying connection will be closed.

ClosedChannelException - if the connection is closed

MaxReadSizeExceededException - if the max read size has been reached (e.g. by calling method IDataSource.readStringByDelimiter(String, int)). Throwing this exception causes that the underlying connection will be closed.

onDisconnect

public boolean onDisconnect(INonBlockingConnection connection)
                     throws IOException,
                            BufferUnderflowException,
                            MaxReadSizeExceededException

handles disconnecting of a connection

Specified by:

onDisconnect in interface IDisconnectHandler

Parameters:

connection - the closed connection

Returns:

true for positive result of handling, false for negative result of handling

Throws:

IOException - If some I/O error occurs.

BufferUnderflowException

MaxReadSizeExceededException

onIdleTimeout

public boolean onIdleTimeout(INonBlockingConnection connection)
                      throws IOException,
                             BufferUnderflowException,
                             MaxReadSizeExceededException

handles the idle timeout.

Specified by:

onIdleTimeout in interface IIdleTimeoutHandler

Parameters:

connection - the underlying connection

Returns:

true if the timeout event has been handled (in case of false the connection will be closed by the server)

Throws:

IOException - if an error occurs. Throwing this exception causes that the underlying connection will be closed.

BufferUnderflowException

MaxReadSizeExceededException

onConnectionTimeout

public boolean onConnectionTimeout(INonBlockingConnection connection)
                            throws IOException,
                                   BufferUnderflowException,
                                   MaxReadSizeExceededException

handles the connection timeout.

Specified by:

onConnectionTimeout in interface IConnectionTimeoutHandler

Parameters:

connection - the underlying connection

Returns:

true if the timeout event has been handled (in case of false the connection will be closed by the server)

Throws:

IOException - if an error occurs. Throwing this exception causes that the underlying connection will be closed.

BufferUnderflowException

MaxReadSizeExceededException