com.connecterra.ale.reader
Class CharacterStreamDeviceChannel

java.lang.Object
  com.connecterra.ale.reader.DeviceChannel
      com.connecterra.ale.reader.SocketDeviceChannel
          com.connecterra.ale.reader.CharacterStreamDeviceChannel

public class CharacterStreamDeviceChannel
extends com.connecterra.ale.reader.SocketDeviceChannel

A DeviceChannel implemented by a TCP connection initiated by the device driver. It extends the SocketDeviceChannel to provide a character-based interface and buffering on input.

Nested Class Summary

Nested classes/interfaces inherited from class com.connecterra.ale.reader.SocketDeviceChannel

com.connecterra.ale.reader.SocketDeviceChannel.BlockingSocketInputListener, com.connecterra.ale.reader.SocketDeviceChannel.SocketInputListener

Nested classes/interfaces inherited from class com.connecterra.ale.reader.DeviceChannel

DeviceChannel.AbstractOpenChannel, DeviceChannel.MarkingInputStream

Constructor Summary

CharacterStreamDeviceChannel(PluginConfig config)
Creates a new CharacterStreamDeviceChannel instance where the remote host is read from the hostname and port parameters in the given PluginConfig.

CharacterStreamDeviceChannel(PluginConfig config, String portName)
Creates a new CharacterStreamDeviceChannel instance where the remote host is read from the hostname parameter and the remote port is read from the parameter named by the portName argument in the given PluginConfig.

Method Summary

BufferedReader	getReader() Returns a BufferedReader for reading from an open channel.
Writer	getWriter()
boolean	ready()

Methods inherited from class com.connecterra.ale.reader.SocketDeviceChannel

addDeviceAttributes, addToPluginMeta, addToPluginMeta, close, getHostname, getInputStream, getOutputStream, getPort, getSocket, open, setBlockingListener, setListener, toString

Methods inherited from class com.connecterra.ale.reader.DeviceChannel

getLogger, getReactor, markUsed, reactivateChannels

Methods inherited from class java.lang.Object

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

Constructor Detail

CharacterStreamDeviceChannel

public CharacterStreamDeviceChannel(PluginConfig config,
                                    String portName)
                             throws com.connecterra.ale.resources.PluginLoadException

Creates a new CharacterStreamDeviceChannel instance where the remote host is read from the hostname parameter and the remote port is read from the parameter named by the portName argument in the given PluginConfig. The timeout for socket operations is read from the socketTimeout parameter in the PluginConfig.

Parameters:

config - a PluginConfig value

portName - the String key name of the endpoint port parameter

Throws:

com.connecterra.ale.resources.PluginLoadException - if a configuration error occurs

CharacterStreamDeviceChannel

public CharacterStreamDeviceChannel(PluginConfig config)
                             throws com.connecterra.ale.resources.PluginLoadException

Creates a new CharacterStreamDeviceChannel instance where the remote host is read from the hostname and port parameters in the given PluginConfig. The timeout for socket operations is read from the socketTimeout parameter in the PluginConfig.

Parameters:

config - a PluginConfig value

Throws:

com.connecterra.ale.resources.PluginLoadException - if a configuration error occurs

Method Detail

getWriter

public Writer getWriter()
                 throws IOException

Returns:

a Writer for writing to an open channel.

Throws:

IOException - if the channel is not open

getReader

public BufferedReader getReader()
                         throws IOException

Returns a BufferedReader for reading from an open channel.

If this method is used by a driver which expects to receive data asynchronously, and this method is used to read a synchronous result from a command, then there is a pitfall to avoid: if the device sent asynchronous data before the synchronous command was received and processed, then the command "response" may actually be the asynchronous data. The reader should be aware of this, and be prepared to handle the asynchronous data, either immediately or by queueing it for later processing.

Returns:

a BufferedReader for reading from an open channel.

Throws:

IOException - if the channel is not open

ready

public boolean ready()
              throws IOException

Overrides:

ready in class com.connecterra.ale.reader.SocketDeviceChannel

Returns:

true if an input operation on the result of CharacterStreamDeviceChannel.getReader() is guaranteed not to block

Throws:

IOException - if the channel is not open