Package com.bytedesk.call.esl.client.internal

Class AbstractEslClientHandler

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelInboundHandlerAdapter

io.netty.channel.SimpleChannelInboundHandler<EslMessage>

com.bytedesk.call.esl.client.internal.AbstractEslClientHandler

All Implemented Interfaces:

io.netty.channel.ChannelHandler, io.netty.channel.ChannelInboundHandler

Direct Known Subclasses:

InboundClientHandler, OutboundClientHandler

public abstract class AbstractEslClientHandler
extends io.netty.channel.SimpleChannelInboundHandler<EslMessage>

Specialised SimpleChannelInboundHandler that implements the logic of an ESL connection that is common to both inbound and outbound clients. This handler expects to receive decoded EslMessage or EslEvent objects. The key responsibilities for this class are:

• To synthesise a synchronous command/response api. All IO operations using the underlying Netty library are intrinsically asynchronous which provides for excellent response and scalability. This class provides for a blocking wait mechanism for responses to commands issued to the server. A key assumption here is that the FreeSWITCH server will process synchronous requests in the order they are received.
• Concrete sub classes are expected to 'terminate' the Netty IO processing pipeline (ie be the 'last' handler).

Note: implementation requirement is that an ExecutionHandler is placed in the processing pipeline prior to this handler. This will ensure that each incoming message is processed in its own thread (although still guaranteed to be processed in the order of receipt).

Nested Class Summary

Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler

io.netty.channel.ChannelHandler.Sharable

Field Summary

Fields

Modifier and Type	Field	Description
private final ConcurrentLinkedQueue<CompletableFuture<EslMessage>>	apiCalls
private final ExecutorService	backgroundJobExecutor
private final ConcurrentHashMap<String,CompletableFuture<EslEvent>>	backgroundJobs
static final String	LINE_TERMINATOR
static final String	MESSAGE_TERMINATOR
private final ReentrantLock	syncLock

Constructor Summary

Constructors

Constructor	Description
AbstractEslClientHandler()

Method Summary

Modifier and Type	Method	Description
protected void	channelRead0(io.netty.channel.ChannelHandlerContext ctx, EslMessage message)
void	exceptionCaught(io.netty.channel.ChannelHandlerContext ctx, Throwable e)
protected abstract void	handleAuthRequest(io.netty.channel.ChannelHandlerContext ctx)
protected abstract void	handleDisconnectionNotice()
protected abstract void	handleEslEvent(io.netty.channel.ChannelHandlerContext ctx, EslEvent event)
protected void	handleEslMessage(io.netty.channel.ChannelHandlerContext ctx, EslMessage message)
CompletableFuture<EslMessage>	sendApiMultiLineCommand(io.netty.channel.Channel channel, List<String> commandLines)	Synthesise a synchronous command/response by creating a callback object which is placed in queue and blocks waiting for another IO thread to process an incoming EslMessage and attach it to the callback.
CompletableFuture<EslMessage>	sendApiSingleLineCommand(io.netty.channel.Channel channel, String command)	Synthesise a synchronous command/response by creating a callback object which is placed in queue and blocks waiting for another IO thread to process an incoming EslMessage and attach it to the callback.
CompletableFuture<EslEvent>	sendBackgroundApiCommand(io.netty.channel.Channel channel, String command)	Returns the Job UUID of that the response event will have.
CompletableFuture<EslMessage>	sendSyncApiCommand(io.netty.channel.Channel channel, String command, String arg)	Sends a FreeSWITCH API command to the channel and blocks, waiting for an immediate response from the server.

Methods inherited from class io.netty.channel.SimpleChannelInboundHandler

acceptInboundMessage, channelRead

Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter

channelActive, channelInactive, channelReadComplete, channelRegistered, channelUnregistered, channelWritabilityChanged, userEventTriggered

Methods inherited from class io.netty.channel.ChannelHandlerAdapter

ensureNotSharable, handlerAdded, handlerRemoved, isSharable

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.netty.channel.ChannelHandler

handlerAdded, handlerRemoved

Field Details

MESSAGE_TERMINATOR

public static final String MESSAGE_TERMINATOR

See Also:

• Constant Field Values

LINE_TERMINATOR

public static final String LINE_TERMINATOR

See Also:

• Constant Field Values

syncLock

private final ReentrantLock syncLock

apiCalls

private final ConcurrentLinkedQueue<CompletableFuture<EslMessage>> apiCalls

backgroundJobs

private final ConcurrentHashMap<String,CompletableFuture<EslEvent>> backgroundJobs

backgroundJobExecutor

private final ExecutorService backgroundJobExecutor

Constructor Details

AbstractEslClientHandler

public AbstractEslClientHandler()

Method Details

exceptionCaught

public void exceptionCaught(io.netty.channel.ChannelHandlerContext ctx,
 Throwable e)
                     throws Exception

Specified by:

exceptionCaught in interface io.netty.channel.ChannelHandler

Specified by:

exceptionCaught in interface io.netty.channel.ChannelInboundHandler

Overrides:

exceptionCaught in class io.netty.channel.ChannelInboundHandlerAdapter

Throws:

Exception

channelRead0

protected void channelRead0(io.netty.channel.ChannelHandlerContext ctx,
 EslMessage message)
                     throws Exception

Specified by:

channelRead0 in class io.netty.channel.SimpleChannelInboundHandler<EslMessage>

Throws:

Exception

handleEslMessage

protected void handleEslMessage(io.netty.channel.ChannelHandlerContext ctx,
 EslMessage message)

sendApiSingleLineCommand

public CompletableFuture<EslMessage> sendApiSingleLineCommand(io.netty.channel.Channel channel,
 String command)

Synthesise a synchronous command/response by creating a callback object which is placed in queue and blocks waiting for another IO thread to process an incoming EslMessage and attach it to the callback.

Parameters:

channel -

command - single string to send

Returns:

the EslMessage attached to this command's callback

sendSyncApiCommand

public CompletableFuture<EslMessage> sendSyncApiCommand(io.netty.channel.Channel channel,
 String command,
 String arg)

Sends a FreeSWITCH API command to the channel and blocks, waiting for an immediate response from the server.

The outcome of the command from the server is returned in an EslMessage object.

Parameters:

channel -

command - API command to send

arg - command arguments

Returns:

an EslMessage containing command results

sendApiMultiLineCommand

public CompletableFuture<EslMessage> sendApiMultiLineCommand(io.netty.channel.Channel channel,
 List<String> commandLines)

Synthesise a synchronous command/response by creating a callback object which is placed in queue and blocks waiting for another IO thread to process an incoming EslMessage and attach it to the callback.

Parameters:

channel -

Returns:

the EslMessage attached to this command's callback

sendBackgroundApiCommand

public CompletableFuture<EslEvent> sendBackgroundApiCommand(io.netty.channel.Channel channel,
 String command)

Returns the Job UUID of that the response event will have.

Parameters:

channel -

command -

Returns:

Job-UUID as a string

handleEslEvent

protected abstract void handleEslEvent(io.netty.channel.ChannelHandlerContext ctx,
 EslEvent event)

handleAuthRequest

protected abstract void handleAuthRequest(io.netty.channel.ChannelHandlerContext ctx)

handleDisconnectionNotice

protected abstract void handleDisconnectionNotice()