ipworks
Class Ipport

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

public class Ipport

extends java.lang.Object

The IPPort bean facilitates TCP/IP communications by providing an easy interface to system TCP/IP 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 bean 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 calling the Connect method or 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 calling the Send method with Text as a parameter, or by assigning the data string to the DataToSend property.

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

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

Field Summary

static int	fwNone
static int	fwSOCKS4
static int	fwSOCKS5
static int	fwTunnel

Constructor Summary

Ipport()

Method Summary

void	addIpportEventListener(IpportEventListener l)
java.lang.String	config(java.lang.String configurationString) Sets or retrieves a beanconfiguration setting.
void	connect(java.lang.String host, int port) Connect to a remote host.
void	disconnect() Disconnect from the remote host.
void	doEvents() Processes events from the internal message queue.
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.
java.lang.String	getFirewallHost() Name or IP address of firewall (optional).
java.lang.String	getFirewallPassword() A password if authentication is to be used when connecting through the firewall.
int	getFirewallPort() Port of the firewall to connect to.
int	getFirewallType() Determines the type of firewall to connect through.
java.lang.String	getFirewallUser() A user name if authentication is to be used connecting through a firewall.
java.lang.String	getLine() Gets a line of text from the server.
java.lang.String	getLocalHost() The name of the local host or user-assigned IP interface through which connections are initiated or accepted.
int	getLocalPort() The TCP port in the local host where IPPort binds.
java.lang.String	getRemoteHost() The address of the remote host.
int	getRemotePort() The TCP port in the remote host.
int	getTimeout() A timeout for the bean.
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.
boolean	isSingleLineMode() Special mode for line-oriented protocols.
void	removeIpportEventListener(IpportEventListener l)
void	send(byte[] text) Send data to the remote host.
void	sendLine(java.lang.String text) Sends a string followed by a newline.
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	setFirewallHost(java.lang.String firewallHost) Name or IP address of firewall (optional).
void	setFirewallPassword(java.lang.String firewallPassword) A password if authentication is to be used when connecting through the firewall.
void	setFirewallPort(int firewallPort) Port of the firewall to connect to.
void	setFirewallType(int firewallType) Determines the type of firewall to connect through.
void	setFirewallUser(java.lang.String firewallUser) A user name if authentication is to be used connecting through a firewall.
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	setLocalHost(java.lang.String localHost) The name of the local host or user-assigned IP interface through which connections are initiated or accepted.
void	setLocalPort(int localPort) The TCP port in the local host where IPPort binds.
void	setRemoteHost(java.lang.String remoteHost) The address of the remote host.
void	setRemotePort(int remotePort) The TCP port in the remote host.
void	setSingleLineMode(boolean singleLineMode) Special mode for line-oriented protocols.
void	setTimeout(int timeout) A timeout for the bean.

Methods inherited from class java.lang.Object

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

Field Detail

fwNone

public static final int fwNone

See Also:

Constant Field Values

fwTunnel

public static final int fwTunnel

See Also:

Constant Field Values

fwSOCKS4

public static final int fwSOCKS4

See Also:

Constant Field Values

fwSOCKS5

public static final int fwSOCKS5

See Also:

Constant Field Values

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, re-enables 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, re-enables data reception.

IPWorksException

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.

Setting the Connected property to True makes the bean 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.

Setting the Connected property to True makes the bean 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.

IPWorksException

setDataToSend

public void setDataToSend(byte[] dataToSend)
                   throws IPWorksException

A string of data to be sent to the remote host.

Assigning a string to the DataToSend property makes the bean send the string to the remote host. The Send method provides similar functionality.

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 fails with exception 10035: "[10035] Operation would block" (WSAEWOULDBLOCK). You can check this error, and then try to send the data again. 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).

IPWorksException

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 CRLF ("\\r\\n") 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 CRLF ("\\r\\n") bytes are discarded.

The EOL property is a binary string. In particular, this means that it can be more than one byte long, and it can contain NULL bytes.

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 CRLF ("\\r\\n") 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 CRLF ("\\r\\n") bytes are discarded.

The EOL property is a binary string. In particular, this means that it can be more than one byte long, and it can contain NULL bytes.

IPWorksException

getFirewallHost

public java.lang.String getFirewallHost()

Name or IP address of firewall (optional).

If a FirewallHost is given, requested connections will be authenticated through the specified firewall when connecting.

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

setFirewallHost

public void setFirewallHost(java.lang.String firewallHost)
                     throws IPWorksException

Name or IP address of firewall (optional).

If a FirewallHost is given, requested connections will be authenticated through the specified firewall when connecting.

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

IPWorksException

getFirewallPassword

public java.lang.String getFirewallPassword()

A password if authentication is to be used when connecting through the firewall.

if FirewallHost is specified, the FirewallUser and FirewallPassword properties are used to connect and authenticate to the given firewall. If the authentication fails, a trappable error is fired.

setFirewallPassword

public void setFirewallPassword(java.lang.String firewallPassword)
                         throws IPWorksException

A password if authentication is to be used when connecting through the firewall.

if FirewallHost is specified, the FirewallUser and FirewallPassword properties are used to connect and authenticate to the given firewall. If the authentication fails, a trappable error is fired.

IPWorksException

getFirewallPort

public int getFirewallPort()

Port of the firewall to connect to.

The TCP port for the FirewallHost . See the description of the FirewallHost property for details.

Note that the FirewallPort is set automatically when FirewallType is set to a valid value. See the description of the FirewallType property for details.

setFirewallPort

public void setFirewallPort(int firewallPort)
                     throws IPWorksException

Port of the firewall to connect to.

The TCP port for the FirewallHost . See the description of the FirewallHost property for details.

Note that the FirewallPort is set automatically when FirewallType is set to a valid value. See the description of the FirewallType property for details.

IPWorksException

getFirewallType

public int getFirewallType()

Determines the type of firewall to connect through.

The applicable values are the following:

fwNone (0)

No firewall (default setting).

fwTunnel (1)

Connect through a tunneling proxy. FirewallPort is set to 80.

fwSOCKS4 (2)

Connect through a SOCKS4 Proxy. FirewallPort is set to 1080.

fwSOCKS5 (3)

Connect through a SOCKS5 Proxy. FirewallPort is set to 1080.

setFirewallType

public void setFirewallType(int firewallType)
                     throws IPWorksException

Determines the type of firewall to connect through.

The applicable values are the following:

fwNone (0)

No firewall (default setting).

fwTunnel (1)

Connect through a tunneling proxy. FirewallPort is set to 80.

fwSOCKS4 (2)

Connect through a SOCKS4 Proxy. FirewallPort is set to 1080.

fwSOCKS5 (3)

Connect through a SOCKS5 Proxy. FirewallPort is set to 1080.

IPWorksException

getFirewallUser

public java.lang.String getFirewallUser()

A user name if authentication is to be used connecting through a firewall.

if FirewallHost is specified, the FirewallUser and FirewallPassword properties are used to connect and authenticate to the given firewall. If the authentication fails, a trappable error is fired.

setFirewallUser

public void setFirewallUser(java.lang.String firewallUser)
                     throws IPWorksException

A user name if authentication is to be used connecting through a firewall.

if FirewallHost is specified, the FirewallUser and FirewallPassword properties are used to connect and authenticate to the given firewall. If the authentication fails, a trappable error is fired.

IPWorksException

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 system TCP/IP stack 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 system TCP/IP stack implementations are not required to support SO_KEEPALIVE.

IPWorksException

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 some Winsock stream sockets) might result in an indefinite delay in closing the connection. Although the bean returns control immediately, the system 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 some Winsock stream sockets) might result in an indefinite delay in closing the connection. Although the bean returns control immediately, the system 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.

IPWorksException

getLocalHost

public java.lang.String getLocalHost()

The name of the local host or user-assigned IP interface through which connections are initiated or accepted.

The LocalHost property contains the name of the local host as obtained by the gethostname() system call, or if the user has assigned an IP address, the value of that address.

In multihomed hosts (machines with more than one IP interface) setting LocalHost to the value of an interface will make the bean initiate connections (or accept in the case of server beans) only through that interface.

If the bean 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).

NOTE: LocalHost is not persistent. You must always set it in code, and never in the property window.

setLocalHost

public void setLocalHost(java.lang.String localHost)
                  throws IPWorksException

The name of the local host or user-assigned IP interface through which connections are initiated or accepted.

The LocalHost property contains the name of the local host as obtained by the gethostname() system call, or if the user has assigned an IP address, the value of that address.

In multihomed hosts (machines with more than one IP interface) setting LocalHost to the value of an interface will make the bean initiate connections (or accept in the case of server beans) only through that interface.

If the bean 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).

NOTE: LocalHost is not persistent. You must always set it in code, and never in the property window.

IPWorksException

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 bean to bind to a specific port (or communication endpoint) in the local machine.

Setting it to 0 (default) enables the system 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 bean to bind to a specific port (or communication endpoint) in the local machine.

Setting it to 0 (default) enables the system 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.

IPWorksException

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.

If the bean is configured to use a SOCKS firewall, the value assigned to this property may be preceded with a "*". If this is the case, the host name is passed to the firewall unresolved and the firewall performs the DNS resolution.

Example (Connecting)

 IPPortControl.RemoteHost = "MyHostNameOrIP"
 IPPortControl.RemotePort = 777
 IPPortControl.Connected = true 

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.

If the bean is configured to use a SOCKS firewall, the value assigned to this property may be preceded with a "*". If this is the case, the host name is passed to the firewall unresolved and the firewall performs the DNS resolution.

Example (Connecting)

 IPPortControl.RemoteHost = "MyHostNameOrIP"
 IPPortControl.RemotePort = 777
 IPPortControl.Connected = true 

IPWorksException

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 this property 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 this property while connected will fail with an error.

IPWorksException

isSingleLineMode

public boolean isSingleLineMode()

Special mode for line-oriented protocols.

When SingleLineMode is True, the bean treats the incoming data stream as lines separated by CRLF, CR, or LF. The EOL property is ignored.

AcceptData will be automatically set to False when SingleLineMode is set to True. Please refer to the GetLine method for more information.

setSingleLineMode

public void setSingleLineMode(boolean singleLineMode)
                       throws IPWorksException

Special mode for line-oriented protocols.

When SingleLineMode is True, the bean treats the incoming data stream as lines separated by CRLF, CR, or LF. The EOL property is ignored.

AcceptData will be automatically set to False when SingleLineMode is set to True. Please refer to the GetLine method for more information.

IPWorksException

getTimeout

public int getTimeout()

A timeout for the bean.

If the Timeout property is set to 0, all operations return immediately, potentially failing with an 'WOULDBLOCK' error if data can't be sent or received immediately.

If Timeout is set to a positive value, the bean will automatically retry each operation that would otherwise result in a 'WOULDBLOCK' error for a maximum of Timeout seconds.

The bean will use DoEvents to enter an efficient wait loop during any potential waiting period, making sure that all system events are processed immediately as they arrive. This ensures that the host application does not "freeze" and remains responsive.

If Timeout expires, and the operation is not yet complete, the bean throws an IPWorksException raises an IPWorksException exception .

Please note that by default, all timeouts are inactivity timeouts , i.e. the timeout period is extended by Timeout seconds when data is successfully sent or received.

Optionally, the behavior of the bean may be changed to absolute timeouts , i.e. the bean will wait for a maximum of Timeout seconds since the beginning of the operation, without extending the timeout period during communications.

This behavior is controlled by theAbsoluteTimeoutconfiguration setting.

The default value for the Timeout property is 0 (asynchronous operation).

setTimeout

public void setTimeout(int timeout)
                throws IPWorksException

A timeout for the bean.

If the Timeout property is set to 0, all operations return immediately, potentially failing with an 'WOULDBLOCK' error if data can't be sent or received immediately.

If Timeout is set to a positive value, the bean will automatically retry each operation that would otherwise result in a 'WOULDBLOCK' error for a maximum of Timeout seconds.

The bean will use DoEvents to enter an efficient wait loop during any potential waiting period, making sure that all system events are processed immediately as they arrive. This ensures that the host application does not "freeze" and remains responsive.

If Timeout expires, and the operation is not yet complete, the bean throws an IPWorksException raises an IPWorksException exception .

Please note that by default, all timeouts are inactivity timeouts , i.e. the timeout period is extended by Timeout seconds when data is successfully sent or received.

Optionally, the behavior of the bean may be changed to absolute timeouts , i.e. the bean will wait for a maximum of Timeout seconds since the beginning of the operation, without extending the timeout period during communications.

This behavior is controlled by theAbsoluteTimeoutconfiguration setting.

The default value for the Timeout property is 0 (asynchronous operation).

IPWorksException

config

public java.lang.String config(java.lang.String configurationString)
                        throws IPWorksException

Sets or retrieves a beanconfiguration setting.

Config is a generic method available in every bean. It is used to set and retrieveconfiguration settingsfor the bean.

Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the bean, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY , you must call Config("PROPERTY=VALUE") , where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY") . The value will be returned as a string.

IPWorksException

connect

public void connect(java.lang.String host,
                    int port)
             throws IPWorksException

Connect to a remote host.

Calling this method is equivalent to setting the RemoteHost property to Host , setting RemotePort to Port , and then setting the Connected property to True.

Example (Connecting)

 IPPortControl.Connect("MyHostNameOrIP", 777) 

IPWorksException

disconnect

public void disconnect()
                throws IPWorksException

Disconnect from the remote host.

Calling this method is equivalent to setting the Connected property to False.

IPWorksException

doEvents

public void doEvents()
              throws IPWorksException

Processes events from the internal message queue.

When DoEvents is called, the bean processes any available events. If no events are available, it waits for a preset period of time, and then returns.

IPWorksException

getLine

public java.lang.String getLine()
                         throws IPWorksException

Gets a line of text from the server.

This method is an alternative method of receiving data for line-oriented protocols. The bean will block if necessary and then return the received line. AcceptData will be automatically set to True when the method is called, and then back to False after a line is received.

Please refer to the SingleLineMode property for more information.

IPWorksException

send

public void send(byte[] text)
          throws IPWorksException

Send data to the remote host.

Calling this method is equivalent to setting the DataToSend property to Text .

IPWorksException

sendLine

public void sendLine(java.lang.String text)
              throws IPWorksException

Sends a string followed by a newline.

This method is used for sending data with line-oriented protocols. The line is followed by CRLF ("\\r\\n") .

Please refer to the GetLine method and SingleLineMode property for more information.

IPWorksException

addIpportEventListener

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

java.util.TooManyListenersException

removeIpportEventListener

public void removeIpportEventListener(IpportEventListener l)