info.pppc.base.plugin.common.util

Class TimeoutConnector

java.lang.Object

info.pppc.base.plugin.common.util.TimeoutConnector

All Implemented Interfaces:

IConnector, IStreamConnector

public class TimeoutConnector
extends java.lang.Object
implements IStreamConnector

The timeout connector implements a simple protocol to establish a connection between two entities that are using unbuffered output streams that do not provide a connection detection. To do this the participating entities will exchange two sync messages before sending data. The synchronization is done in the constructor of the connector. If the synchronization does not take place during the timeout, the connection establishment will fail with an exception. Similarly, if the entities refrain from exchanging data for the timeout value, the connection will be considered to be dead. The original purpose of this connector is to establish a connection between sun spots and a base station running on some other device via usb. Since the sun spot and the base station may not be able to reliably detect their presence and their absence (e.g. if a user simply disconnects the sun spot from the usb port), it is necessary to have some simple handshake and keep alive mechanism that must be implemented at the application layer.

Author:

Marcus Handte

Constructor Summary

Constructors

Constructor and Description
TimeoutConnector(IPlugin plugin, IOperator operator, java.io.InputStream in, java.io.OutputStream out, boolean mode, long timeout) Creates a new timeout connector for the specified plug-in.

Method Summary

Methods

Modifier and Type	Method and Description
java.io.InputStream	getInputStream() Returns the input stream of the connector.
java.io.OutputStream	getOutputStream() Returns the output stream of the connector.
IPlugin	getPlugin() Returns the plug-in that has created the connector or null if none.
void	release() Closes the input and output streams of the connector.

Methods inherited from class java.lang.Object

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

Constructor Detail

TimeoutConnector

public TimeoutConnector(IPlugin plugin,
                IOperator operator,
                java.io.InputStream in,
                java.io.OutputStream out,
                boolean mode,
                long timeout)
                 throws java.io.IOException

Creates a new timeout connector for the specified plug-in. It uses the specified operator to execute operations asynchronously. Furthermore, it uses the specified input and output streams to establish a connection. The mode flag determines which end of the connection will initiate the handshake.

Parameters:

plugin - The plug-in that is requesting the connector or null, if none.

operator - The operator that is used to schedule more threads.

in - The input stream used to establish a connection.

out - The output stream used to establish a connection.

mode - False to initiate the handshake on this side of the connection, true to initiate the handshake on the opposing side.

timeout - The timeout during the handshake and for the reception of data. The other end of the connection must send at least one byte in a timely manner in order to avoid disconnections.

Throws:

java.io.IOException - Thrown if the handshake fails.

Method Detail

getInputStream

public java.io.InputStream getInputStream()
                                   throws java.io.IOException

Returns the input stream of the connector.

Specified by:

getInputStream in interface IStreamConnector

Returns:

The input stream.

Throws:

java.io.IOException - Thrown if the connector cannot open an input stream.

getOutputStream

public java.io.OutputStream getOutputStream()
                                     throws java.io.IOException

Returns the output stream of the connector.

Specified by:

getOutputStream in interface IStreamConnector

Returns:

The output stream.

Throws:

java.io.IOException - Thrown if the connector cannot open an output stream.

getPlugin

public IPlugin getPlugin()

Returns the plug-in that has created the connector or null if none.

Specified by:

getPlugin in interface IConnector

Returns:

The plug-in that created the connector.

release

public void release()

Closes the input and output streams of the connector.

Specified by:

release in interface IConnector