IP*Works!

ipworks
Class Ipport

java.lang.Object
  |
  +--ipworks.Ipport

public class Ipport
extends java.lang.Object

The IPPort class facilitates TCP/IP communications by providing an easy interface to Winsock functions. It allows a client application to communicate with a server using stream sockets.

Our main goal in designing IPPort was ease of use. The class has a minimum of properties and five events: Connected , DataIn , Disconnected , ReadyToSend , and Error . The events are relatively self-explanatory.

The connection is attempted by setting the Connected property to True, and then waiting for the Connected event. The destination is defined by setting RemoteHost and RemotePort . Data is sent by assigning the data string to the DataToSend property.

To disconnect, you just set the Connected property to False. The Linger property controls how the connection is terminated.

The operation of the class is almost completely asynchronous. All the calls except the ones that deal with domain name resolution, operate through Windows messages (no blocking calls). The gain in performance is considerable when compared to using blocking calls.


Constructor Summary
Ipport()
           
 
Method Summary
 void addIpportEventListener(IpportEventListener l)
           
 void fireConnected(int statusCode, java.lang.String description)
          Fired immediately after a connection completes (or fails).
 void fireDataIn(byte[] text, boolean EOL)
          Fired when data (complete lines) comes in.
 void fireDisconnected(int statusCode, java.lang.String description)
          Fired when a connection is closed.
 void fireError(int errorCode, java.lang.String description)
          Information about errors during data delivery.
 void fireReadyToSend()
          Fired when IPPort is ready to send data.
 int getBytesSent()
          The number of bytes actually sent after an assignment to DataToSend .
 byte[] getEOL()
          Used to break the incoming data stream into chunks separated by EOL.
 int getInBufferSize()
          The size in bytes of the incoming queue of the socket.
 java.lang.String getLocalHost()
          The name of the local host.
 int getLocalPort()
          The TCP port in the local host where IPPort binds.
 int getMaxLineLength()
          The maximum amount of data to accumulate when no EOL is found.
 int getOutBufferSize()
          The size in bytes of the outgoing queue of the socket.
 java.lang.String getRemoteHost()
          The address of the remote host.
 int getRemotePort()
          The TCP port in the remote host.
 boolean isAcceptData()
          Enables or disables data reception (the DataIn event).
 boolean isConnected()
          Triggers a connection or disconnection.
 boolean isKeepAlive()
          When True, KEEPALIVE packets are enabled (for long connections).
 boolean isLinger()
          When set to True, connections are terminated gracefully.
 void removeIpportEventListener(IpportEventListener l)
           
 void setAcceptData(boolean acceptData)
          Enables or disables data reception (the DataIn event).
 void setConnected(boolean connected)
          Triggers a connection or disconnection.
 void setDataToSend(byte[] dataToSend)
          A string of data to be sent to the remote host.
 void setEOL(byte[] EOL)
          Used to break the incoming data stream into chunks separated by EOL.
 void setInBufferSize(int inBufferSize)
          The size in bytes of the incoming queue of the socket.
 void setKeepAlive(boolean keepAlive)
          When True, KEEPALIVE packets are enabled (for long connections).
 void setLinger(boolean linger)
          When set to True, connections are terminated gracefully.
 void setLocalPort(int localPort)
          The TCP port in the local host where IPPort binds.
 void setMaxLineLength(int maxLineLength)
          The maximum amount of data to accumulate when no EOL is found.
 void setOutBufferSize(int outBufferSize)
          The size in bytes of the outgoing queue of the socket.
 void setRemoteHost(java.lang.String remoteHost)
          The address of the remote host.
 void setRemotePort(int remotePort)
          The TCP port in the remote host.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

Ipport

public Ipport()
Method Detail

isAcceptData

public boolean isAcceptData()
Enables or disables data reception (the DataIn event). Setting the property to False, temporarily disables data reception (and the DataIn event). Setting the property to True, reenables data reception.


setAcceptData

public void setAcceptData(boolean acceptData)
                   throws IPWorksException
Enables or disables data reception (the DataIn event). Setting the property to False, temporarily disables data reception (and the DataIn event). Setting the property to True, reenables data reception.


getBytesSent

public int getBytesSent()
The number of bytes actually sent after an assignment to DataToSend . The BytesSent property shows how many bytes were sent after the last assignment to DataToSend . Please check the DataToSend property for more information.


isConnected

public boolean isConnected()
Triggers a connection or disconnection. Action property. Setting the Connected property to True makes the class attempt to connect to the host identified by the RemoteHost property. If successful, after the connection is achieved the value of the property changes to True and the Connected event is fired.

Setting Connected to False closes the connection. How and when the connection is closed is controlled by the Linger property.


setConnected

public void setConnected(boolean connected)
                  throws IPWorksException
Triggers a connection or disconnection. Action property. Setting the Connected property to True makes the class attempt to connect to the host identified by the RemoteHost property. If successful, after the connection is achieved the value of the property changes to True and the Connected event is fired.

Setting Connected to False closes the connection. How and when the connection is closed is controlled by the Linger property.


setDataToSend

public void setDataToSend(byte[] dataToSend)
                   throws IPWorksException
A string of data to be sent to the remote host. The DataToSend property is an action property. Assigning a string to this property makes the class send the string to the remote host .

If you are sending data to the remote host faster than it can process it, or faster than the network's bandwidth allows, the outgoing queue might fill up. When this happens, DataToSend The BytesSent property shows how many bytes were sent (if any). If 0 bytes were sent, then you can wait for the ReadyToSend event before attempting to send data again. (However, please note that ReadyToSend is not fired when part of the data is successfully sent).


getEOL

public byte[] getEOL()
Used to break the incoming data stream into chunks separated by EOL. The EOL property is used to define boundaries in the input stream using the value of the property.

The EOL property is especially useful with ASCII files. Setting it to "\\n" (newline) enables splitting of the incoming ASCII text stream into lines. In this case, one event is fired for each line received (as well as in packet boundaries). The "\\n" characters are discarded.

The EOL property is a byte array string. In particular, this means that it can be more than one character long, and it can contain NULL ('\\0') characters as well.


setEOL

public void setEOL(byte[] EOL)
            throws IPWorksException
Used to break the incoming data stream into chunks separated by EOL. The EOL property is used to define boundaries in the input stream using the value of the property.

The EOL property is especially useful with ASCII files. Setting it to "\\n" (newline) enables splitting of the incoming ASCII text stream into lines. In this case, one event is fired for each line received (as well as in packet boundaries). The "\\n" characters are discarded.

The EOL property is a byte array string. In particular, this means that it can be more than one character long, and it can contain NULL ('\\0') characters as well.


getInBufferSize

public int getInBufferSize()
The size in bytes of the incoming queue of the socket. This is the size of an internal queue in the Winsock stack. You can increase or decrease its size depending on the amount of data that you will be receiving. Increasing the value of the InBufferSize property can provide drastic improvements in performance in some cases.

Some TCP/IP implementations do not support variable buffer sizes. If that is the case, when a new connection is attempted the InBufferSize property reverts to its defined size. The same happens if you attempt to make it too large or too small.


setInBufferSize

public void setInBufferSize(int inBufferSize)
                     throws IPWorksException
The size in bytes of the incoming queue of the socket. This is the size of an internal queue in the Winsock stack. You can increase or decrease its size depending on the amount of data that you will be receiving. Increasing the value of the InBufferSize property can provide drastic improvements in performance in some cases.

Some TCP/IP implementations do not support variable buffer sizes. If that is the case, when a new connection is attempted the InBufferSize property reverts to its defined size. The same happens if you attempt to make it too large or too small.


isKeepAlive

public boolean isKeepAlive()
When True, KEEPALIVE packets are enabled (for long connections). The KeepAlive enables the SO_KEEPALIVE option on the socket. This option prevents long connections from timing out in case of inactivity.

Please note that Winsock implementations are not required to support SO_KEEPALIVE.


setKeepAlive

public void setKeepAlive(boolean keepAlive)
                  throws IPWorksException
When True, KEEPALIVE packets are enabled (for long connections). The KeepAlive enables the SO_KEEPALIVE option on the socket. This option prevents long connections from timing out in case of inactivity.

Please note that Winsock implementations are not required to support SO_KEEPALIVE.


isLinger

public boolean isLinger()
When set to True, connections are terminated gracefully. The Linger property controls how a connection is closed. The default is True. In this case the connection is closed only after all the data is sent. Setting it to False forces an abrupt (hard) disconnection. Any data that were in the sending queue may be lost.

The default behavior (which is also the default mode for Winsock stream sockets) might result in an indefinite delay in closing the connection. Although the class returns control immediately, Winsock might indefinitely hold system resources until all pending data are sent (even after your application closes). This means that valuable system resources might be wasted.

Setting Linger to False forces an immediate disconnection. If you know that the other side has received all the data you had sent (by a client acknowledgment, for example), setting Linger to False might be the appropriate course of action.


setLinger

public void setLinger(boolean linger)
               throws IPWorksException
When set to True, connections are terminated gracefully. The Linger property controls how a connection is closed. The default is True. In this case the connection is closed only after all the data is sent. Setting it to False forces an abrupt (hard) disconnection. Any data that were in the sending queue may be lost.

The default behavior (which is also the default mode for Winsock stream sockets) might result in an indefinite delay in closing the connection. Although the class returns control immediately, Winsock might indefinitely hold system resources until all pending data are sent (even after your application closes). This means that valuable system resources might be wasted.

Setting Linger to False forces an immediate disconnection. If you know that the other side has received all the data you had sent (by a client acknowledgment, for example), setting Linger to False might be the appropriate course of action.


getLocalHost

public java.lang.String getLocalHost()
The name of the local host. When connected, the IP address of the interface through which the connection was made. The LocalHost property contains the name of the local host as obtained by the gethostname() Winsock call.

If the class is connected, the LocalHost property shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multihomed hosts (machines with more than one IP interface).


getLocalPort

public int getLocalPort()
The TCP port in the local host where IPPort binds. The LocalPort property must be set before a connection is attempted. It instructs the class to bind to a specific port (or communication endpoint) in the local machine.

Setting it to 0 (default) enables Winsock to choose a port at random. The chosen port will be shown by the LocalPort property after the connection is established.

LocalPort cannot be changed once a connection is made. Any attempt to set the LocalPort property when a connection is active will generate an error.

The LocalPort property is useful when trying to connect to services that require a trusted port in the client side. An example is the remote shell (rsh) service in UNIX systems.


setLocalPort

public void setLocalPort(int localPort)
                  throws IPWorksException
The TCP port in the local host where IPPort binds. The LocalPort property must be set before a connection is attempted. It instructs the class to bind to a specific port (or communication endpoint) in the local machine.

Setting it to 0 (default) enables Winsock to choose a port at random. The chosen port will be shown by the LocalPort property after the connection is established.

LocalPort cannot be changed once a connection is made. Any attempt to set the LocalPort property when a connection is active will generate an error.

The LocalPort property is useful when trying to connect to services that require a trusted port in the client side. An example is the remote shell (rsh) service in UNIX systems.


getMaxLineLength

public int getMaxLineLength()
The maximum amount of data to accumulate when no EOL is found. The MaxLineLength is the size of an internal buffer, which holds received data while waiting for an EOL string.

If an EOL string is found in the input stream before MaxLineLength characters are received, the DataIn event is fired with the EOL parameter set to True, and the buffer is reset.

If no EOL is found, and MaxLineLength characters are accumulated in the buffer, the DataIn event is fired with the EOL parameter set to False, and the buffer is reset.

The minimum value for MaxLineLength is 256.


setMaxLineLength

public void setMaxLineLength(int maxLineLength)
                      throws IPWorksException
The maximum amount of data to accumulate when no EOL is found. The MaxLineLength is the size of an internal buffer, which holds received data while waiting for an EOL string.

If an EOL string is found in the input stream before MaxLineLength characters are received, the DataIn event is fired with the EOL parameter set to True, and the buffer is reset.

If no EOL is found, and MaxLineLength characters are accumulated in the buffer, the DataIn event is fired with the EOL parameter set to False, and the buffer is reset.

The minimum value for MaxLineLength is 256.


getOutBufferSize

public int getOutBufferSize()
The size in bytes of the outgoing queue of the socket. This is the size of an internal queue in the Winsock stack. You can increase or decrease its size depending on the amount of data that you will be sending. Increasing the value of the OutBufferSize property can provide drastic improvements in performance in some cases.

Some TCP/IP implementations do not support variable buffer sizes. If that is the case, when a new connection is attempted the OutBufferSize property reverts to its defined size. The same happens if you attempt to make it too large or too small.


setOutBufferSize

public void setOutBufferSize(int outBufferSize)
                      throws IPWorksException
The size in bytes of the outgoing queue of the socket. This is the size of an internal queue in the Winsock stack. You can increase or decrease its size depending on the amount of data that you will be sending. Increasing the value of the OutBufferSize property can provide drastic improvements in performance in some cases.

Some TCP/IP implementations do not support variable buffer sizes. If that is the case, when a new connection is attempted the OutBufferSize property reverts to its defined size. The same happens if you attempt to make it too large or too small.


getRemoteHost

public java.lang.String getRemoteHost()
The address of the remote host. Domain names are resolved to IP addresses. The RemoteHost property specifies the IP address (IP number in dotted internet format) or Domain Name of the remote host. It is set before a connection is attempted and cannot be changed once a connection is established.

If the RemoteHost property is set to a Domain Name, a DNS request is initiated, and upon successful termination of the request, the RemoteHost property is set to the corresponding address. If the search is not successful, an error is returned.


setRemoteHost

public void setRemoteHost(java.lang.String remoteHost)
                   throws IPWorksException
The address of the remote host. Domain names are resolved to IP addresses. The RemoteHost property specifies the IP address (IP number in dotted internet format) or Domain Name of the remote host. It is set before a connection is attempted and cannot be changed once a connection is established.

If the RemoteHost property is set to a Domain Name, a DNS request is initiated, and upon successful termination of the request, the RemoteHost property is set to the corresponding address. If the search is not successful, an error is returned.


getRemotePort

public int getRemotePort()
The TCP port in the remote host. The RemotePort property specifies a service port on the remote host to connect to.

A valid port number (a value between 1 and 65535) is required for the connection to take place. The property must be set before a connection is attempted and cannot be changed once a connection is established. Any attempt to change the RemotePort while connected will fail with an error.


setRemotePort

public void setRemotePort(int remotePort)
                   throws IPWorksException
The TCP port in the remote host. The RemotePort property specifies a service port on the remote host to connect to.

A valid port number (a value between 1 and 65535) is required for the connection to take place. The property must be set before a connection is attempted and cannot be changed once a connection is established. Any attempt to change the RemotePort while connected will fail with an error.


fireConnected

public void fireConnected(int statusCode,
                          java.lang.String description)
Fired immediately after a connection completes (or fails). (Called internally to dispatch the event.)
See Also:
IpportConnectedEvent

fireDataIn

public void fireDataIn(byte[] text,
                       boolean EOL)
Fired when data (complete lines) comes in. (Called internally to dispatch the event.)
See Also:
IpportDataInEvent

fireDisconnected

public void fireDisconnected(int statusCode,
                             java.lang.String description)
Fired when a connection is closed. (Called internally to dispatch the event.)
See Also:
IpportDisconnectedEvent

fireError

public void fireError(int errorCode,
                      java.lang.String description)
Information about errors during data delivery. (Called internally to dispatch the event.)
See Also:
IpportErrorEvent

fireReadyToSend

public void fireReadyToSend()
Fired when IPPort is ready to send data. (Called internally to dispatch the event.)
See Also:
IpportReadyToSendEvent

addIpportEventListener

public void addIpportEventListener(IpportEventListener l)
                            throws java.util.TooManyListenersException

removeIpportEventListener

public void removeIpportEventListener(IpportEventListener l)

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