ubc.cs.JLog.Foundation
Class jPrologServices

java.lang.Object
  ubc.cs.JLog.Foundation.jPrologServices

public class jPrologServices
extends Object

This class is the near complete environment for a Prolog environment. It contains the rules database, a registery of predicates and operators needed for parsing Prolog code, a connection to a graphical display environment, connections to text input and output consoles, several broadcasters to notify observers of several possible events, and some debugging attributes. It does not, however, contain the prover itself.

Version:

%I%, %G%

Author:

Glendon Holst

Field Summary

protected Object	animation
protected jPrologServiceBroadcaster	beginConsult
protected jPrologServiceBroadcaster	beginQuery
protected BufferedReader	current_input
protected PrintWriter	current_output
protected jKnowledgeBase	database
protected boolean	debugging
protected jPrologServiceBroadcaster	debugMessages
protected BufferedReader	default_input
protected PrintWriter	default_output
protected jPrologServiceBroadcaster	endConsult
protected jPrologServiceBroadcaster	endQuery
protected boolean	fail_unknown_predicate
protected iPrologFileServices	fileservices
protected pOperatorRegistry	operators
protected pPredicateRegistry	predicates
protected Random	rand
protected jPrologServiceBroadcaster	retryQuery
protected jPrologServiceBroadcaster	stateChanged
protected jPrologServiceThread	thread
protected jPrologServiceBroadcaster	threadStopped

Constructor Summary

jPrologServices(jKnowledgeBase kb, pPredicateRegistry pr, pOperatorRegistry or)

Method Summary

void	addBeginConsultListener(jPrologServiceListener l)
void	addBeginQueryListener(jPrologServiceListener l)
void	addDebugMessagesListener(jPrologServiceListener l)
void	addEndConsultListener(jPrologServiceListener l)
void	addEndQueryListener(jPrologServiceListener l)
void	addRetryQueryListener(jPrologServiceListener l)
void	addStateChangedListener(jPrologServiceListener l)
void	addThreadStoppedListener(jPrologServiceListener l)
Object	getAnimationEnvironment()
boolean	getDebugging()
boolean	getFailUnknownPredicate() Get the behaviour for unknown predicates.
iPrologFileServices	getFileServices() Gets the file services object.
BufferedReader	getInput()
jKnowledgeBase	getKnowledgeBase()
pOperatorRegistry	getOperatorRegistry()
PrintWriter	getOutput()
pPredicateRegistry	getPredicateRegistry()
Random	getRandomGenerator()
static String	getRequiredCreditInfo() This function returns the credit assignment and copyright informaiton string.
boolean	isAvailable() Returns whether the prolog services are busy or not.
Class	loadClass(String lib, String classname)
void	loadLibrary(String lib)
protected void	loadLibraryFromTOC(String lib, InputStream toc_is)
protected void	loadLibraryTOCParseGenericOperator(String lib, StreamTokenizer tokenizer)
protected void	loadLibraryTOCParseGenericPredicate(String lib, StreamTokenizer tokenizer)
protected void	loadLibraryTOCParseLoadClass(String lib, StreamTokenizer tokenizer)
void	printOutput(String s)
protected void	registerPredefinedInstance(String lib, Object obj_inst)
protected void	registerPredicateOperatorEntryInstance(String lib, Object obj_inst)
void	release() Releases the current thread as a user of jPrologServices.
void	removeBeginConsultListener(jPrologServiceListener l)
void	removeBeginQueryListener(jPrologServiceListener l)
void	removeDebugMessagesListener(jPrologServiceListener l)
void	removeEndConsultListener(jPrologServiceListener l)
void	removeEndQueryListener(jPrologServiceListener l)
void	removeRetryQueryListener(jPrologServiceListener l)
void	removeStateChangedListener(jPrologServiceListener l)
void	removeThreadStoppedListener(jPrologServiceListener l)
void	resetInput()
void	resetKnowledgeBase()
void	resetOutput()
void	resume()
void	setAnimationEnvironment(Object ae)
void	setDebugging(boolean dp)
void	setDefaultInput(BufferedReader i)
void	setDefaultOutput(PrintWriter o)
void	setFailUnknownPredicate(boolean fp) Set the behaviour for unknown predicates.
void	setFileServices(iPrologFileServices fs) Sets the file services object.
void	setInput(BufferedReader i)
void	setOutput(PrintWriter o)
void	start()
boolean	start(jPrologServiceThread t) Starts a prolog services of a given type.
void	stop() Forcefully terminates the current user thread.
void	suspend()

Methods inherited from class java.lang.Object

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

Field Detail

thread

protected jPrologServiceThread thread

database

protected jKnowledgeBase database

predicates

protected pPredicateRegistry predicates

operators

protected pOperatorRegistry operators

rand

protected Random rand

beginQuery

protected jPrologServiceBroadcaster beginQuery

retryQuery

protected jPrologServiceBroadcaster retryQuery

endQuery

protected jPrologServiceBroadcaster endQuery

beginConsult

protected jPrologServiceBroadcaster beginConsult

endConsult

protected jPrologServiceBroadcaster endConsult

threadStopped

protected jPrologServiceBroadcaster threadStopped

debugMessages

protected jPrologServiceBroadcaster debugMessages

stateChanged

protected jPrologServiceBroadcaster stateChanged

default_output

protected PrintWriter default_output

current_output

protected PrintWriter current_output

default_input

protected BufferedReader default_input

current_input

protected BufferedReader current_input

fileservices

protected iPrologFileServices fileservices

animation

protected Object animation

debugging

protected boolean debugging

fail_unknown_predicate

protected boolean fail_unknown_predicate

Constructor Detail

jPrologServices

public jPrologServices(jKnowledgeBase kb,
                       pPredicateRegistry pr,
                       pOperatorRegistry or)

Method Detail

getRequiredCreditInfo

public static String getRequiredCreditInfo()

This function returns the credit assignment and copyright informaiton string. It must be preserved by authors of derivative works.

Returns:

The credit and information string.

addBeginQueryListener

public void addBeginQueryListener(jPrologServiceListener l)

addRetryQueryListener

public void addRetryQueryListener(jPrologServiceListener l)

addEndQueryListener

public void addEndQueryListener(jPrologServiceListener l)

addBeginConsultListener

public void addBeginConsultListener(jPrologServiceListener l)

addEndConsultListener

public void addEndConsultListener(jPrologServiceListener l)

removeBeginQueryListener

public void removeBeginQueryListener(jPrologServiceListener l)

removeRetryQueryListener

public void removeRetryQueryListener(jPrologServiceListener l)

removeEndQueryListener

public void removeEndQueryListener(jPrologServiceListener l)

removeBeginConsultListener

public void removeBeginConsultListener(jPrologServiceListener l)

removeEndConsultListener

public void removeEndConsultListener(jPrologServiceListener l)

addThreadStoppedListener

public void addThreadStoppedListener(jPrologServiceListener l)

removeThreadStoppedListener

public void removeThreadStoppedListener(jPrologServiceListener l)

addDebugMessagesListener

public void addDebugMessagesListener(jPrologServiceListener l)

removeDebugMessagesListener

public void removeDebugMessagesListener(jPrologServiceListener l)

addStateChangedListener

public void addStateChangedListener(jPrologServiceListener l)

removeStateChangedListener

public void removeStateChangedListener(jPrologServiceListener l)

isAvailable

public boolean isAvailable()

Returns whether the prolog services are busy or not.

Returns:

true if there is not already a busy thread, false otherwise.

start

public boolean start(jPrologServiceThread t)

Starts a prolog services of a given type.

Parameters:

t - The thread which will use the prolog services.

Returns:

true if the thread is accepted.

start

public void start()

stop

public void stop()

Forcefully terminates the current user thread. The thread may broadcast a 'stopped' message.

release

public void release()

Releases the current thread as a user of jPrologServices. This should be done only by the threads themselves, after they have finished using the services provided by this instance.

suspend

public void suspend()

resume

public void resume()

resetKnowledgeBase

public void resetKnowledgeBase()

getKnowledgeBase

public jKnowledgeBase getKnowledgeBase()

getPredicateRegistry

public pPredicateRegistry getPredicateRegistry()

getOperatorRegistry

public pOperatorRegistry getOperatorRegistry()

setAnimationEnvironment

public void setAnimationEnvironment(Object ae)

getAnimationEnvironment

public Object getAnimationEnvironment()

loadLibrary

public void loadLibrary(String lib)
                 throws IOException

Throws:

IOException

loadLibraryFromTOC

protected void loadLibraryFromTOC(String lib,
                                  InputStream toc_is)
                           throws IOException

Throws:

IOException

loadLibraryTOCParseLoadClass

protected void loadLibraryTOCParseLoadClass(String lib,
                                            StreamTokenizer tokenizer)
                                     throws IOException

Throws:

IOException

loadLibraryTOCParseGenericPredicate

protected void loadLibraryTOCParseGenericPredicate(String lib,
                                                   StreamTokenizer tokenizer)
                                            throws IOException

Throws:

IOException

loadLibraryTOCParseGenericOperator

protected void loadLibraryTOCParseGenericOperator(String lib,
                                                  StreamTokenizer tokenizer)
                                           throws IOException

Throws:

IOException

loadClass

public Class loadClass(String lib,
                       String classname)

registerPredicateOperatorEntryInstance

protected void registerPredicateOperatorEntryInstance(String lib,
                                                      Object obj_inst)

registerPredefinedInstance

protected void registerPredefinedInstance(String lib,
                                          Object obj_inst)

setDebugging

public void setDebugging(boolean dp)

getDebugging

public boolean getDebugging()

setFailUnknownPredicate

public void setFailUnknownPredicate(boolean fp)

Set the behaviour for unknown predicates. By default missing predicates throw an exception.

Parameters:

fp - If false (default), then missing predicates generate a failing exception (i.e., exception thrown), if true then the query for that predicate fails (i.e., no exception is thrown).

getFailUnknownPredicate

public boolean getFailUnknownPredicate()

Get the behaviour for unknown predicates.

Returns:

If false, then exceptions are thrown for missing predicates, otherwise the query for that predicate fails (no exception thrown).

getRandomGenerator

public Random getRandomGenerator()

setDefaultOutput

public void setDefaultOutput(PrintWriter o)

setOutput

public void setOutput(PrintWriter o)

getOutput

public PrintWriter getOutput()

resetOutput

public void resetOutput()

printOutput

public void printOutput(String s)

setDefaultInput

public void setDefaultInput(BufferedReader i)

setInput

public void setInput(BufferedReader i)

getInput

public BufferedReader getInput()

resetInput

public void resetInput()

setFileServices

public void setFileServices(iPrologFileServices fs)

Sets the file services object. This object is used to access files (remotely or locally depending upon the type of object).

Parameters:

fs - The iPrologFileServices object to use.

getFileServices

public iPrologFileServices getFileServices()

Gets the file services object. This object is used to access files (remotely or locally depending upon the type of object). Since this object may change, any users of the file services object should acquire it once, and hold on to it until they are finished (i.e., separate calls to this method may return different file services).

Returns:

The iPrologFileServices object.