se.sics.prologbeans
Class PrologSession

PrologSession handles the connection with the Prolog Server. Currently only synchronous connections with the server are supported.

PrologSession

PrologSession()

Creates a new PrologSession instance with default Prolog server settings.

getTimeout

public int getTimeout()

Returns the timeout in milliseconds before the connection to the Prolog server is reset (when a query is not answered).

setTimeout

public void setTimeout(int timeout)

Sets the timeout in milliseconds before the connection to the Prolog server is reset (when a query is not answered). Setting the timeout to 0 will disable timeouts for this prolog session. Default is 2000 milliseconds.

Parameters:

timeout - int timeout in milliseconds or 0 to disable timeouts

getPrologSession

public static PrologSession getPrologSession(string name)

This method can only be used in Prologbeans/Java. If called in .NET it will throw an Error.

Parameters:

name - the name of the prolog session

Returns:

the named prolog session or null if no such session could be found

getPrologSession

public static PrologSession getPrologSession(string name, HttpSession httpSession)

This method can only be used in Prologbeans/Java. If called in .NET it will throw an Error.

Parameters:

name - the name of the prolog session

httpSession - the http session

Returns:

the named prolog session

getPort

public int getPort()

Returns the port of the Prolog server.

setPort

public void setPort(int prologServerPort)

Sets the port of the Prolog server (default 8066).

Parameters:

prologServerPort - the port of the Prolog server

getHost

public string getHost()

Returns the host of the Prolog server (exactly as registered in setHost).

setHost

public void setHost(string prologServerHost)

Sets the host of the Prolog server (default is localhost). The host can be specified as either IP-address or host name.

Parameters:

prologServerHost - the host as an IP-address or host name

isAlwaysClosing

public bool isAlwaysClosing()

setAlwaysClose

public void setAlwaysClose(bool close)

setAutoConnect

public void setAutoConnect(bool autoConnect)

Sets the connection mode of this PrologSession. If set to true it will ensure that it is connected to the Prolog server as soon as a call to executeQuery or anything else causing a need for communication happens. This is by default set to true.

isAutoConnecting

public bool isAutoConnecting()

Returns the state of the auto connect mode.

executeQuery

public QueryAnswer executeQuery(string query)

Sends a query to the Prolog server and waits for the answer before returning the QueryAnswer. Anonymous variables (underscore, _), will be ignored, and thus not accessible in the QueryAnswer. executeQuery throws IOException if communication problems with the server occurs. Please note: executeQuery will only return one answer.

Parameters:

query - the query to send to the prolog server. The characters in the query are restricted to ISO-8859-1.

Returns:

the answer from the prolog server

Throws:

IOException - if an error occurs. A possible cause is a timeout.

executeQuery

public QueryAnswer executeQuery(string query, Bindings bindings)

Sends a query to the Prolog server and waits for the answer before returning the QueryAnswer. Bindings are variable bindings for the given query and will ensure that the values are stuffed correctly.

An example:

QueryAnswer answer = executeQuery("evaluate(In,Out)", new Bindings().bind("In","4*9."));

Parameters:

query - the query to send to the prolog server The characters in the query are restricted to ISO-8859-1.

bindings - the variable bindings to use in the query

Returns:

the answer from the prolog server

Throws:

IOException - if an error occurs. A possible cause is a timeout.

executeQuery

public QueryAnswer executeQuery(string query, Bindings bindings, string sessionID)

Sends a query to the Prolog server and waits for the answer before returning the QueryAnswer. Bindings are variable bindings for the given query and will ensure that the values are stuffed correctly.

Parameters:

query - the query to send to the prolog server The characters in the query are restricted to ISO-8859-1.

bindings - the variable bindings to use in the query

sessionID - the session id to give to the prolog server

Returns:

the answer from the prolog server

Throws:

IOException - if an error occurs. A possible cause is a timeout.

connect

public void connect()

Connects to the Prolog server. By default executeQuery will automatically connect to the server when called.

isConnected

public bool isConnected()

Returns true if a connection with the Prolog server is open and false otherwise.

disconnect

public void disconnect()

Closes the connection with the Prolog server. The connection can be opened again with connect.