ubc.cs.JLog.Foundation
Class jAPIQueryThread

java.lang.Object
  java.lang.Thread
      ubc.cs.JLog.Foundation.jPrologServiceThread
          ubc.cs.JLog.Foundation.jRetryQueryThread
              ubc.cs.JLog.Foundation.jAPIQueryThread

All Implemented Interfaces:

Runnable

public class jAPIQueryThread
extends jRetryQueryThread

This class is the thread that attempts to prove a query. It can parse an input string into the predicates of a user query, and it contains the Prolog prover itself. The prover runs as part of this thread. It is similar to jUserQueryThread, but is designed for use via jPrologAPI where the caller is responsible to handling exceptions.

Version:

%I%, %G%

Author:

Glendon Holst

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Thread

Thread.State, Thread.UncaughtExceptionHandler

Field Summary

protected jPrologServiceBroadcaster	beginq
protected jPrologServiceBroadcaster	debugm
protected jPrologServiceBroadcaster	endq
protected jProver	prover
protected String	qinput
protected jPredicateTerms	query
protected boolean	result
protected RuntimeException	result_exception
protected int	retry
protected jPrologServiceBroadcaster	retryq
protected Hashtable	var_prebindings
protected jVariableVector	var_vector

Fields inherited from class ubc.cs.JLog.Foundation.jPrologServiceThread

allow_release, prolog, stopped

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

jAPIQueryThread(jPrologServices ps, Hashtable bindings, String qin)

jAPIQueryThread(jPrologServices ps, String qin)

Method Summary

RuntimeException	getResultException() Returns the RuntimeException thrown by an unsucessful query / retry (e.g., UnknownPredicateException).
Hashtable	getResultHashtable() Returns a hashtable of the variable bindings, as a result of a sucessful query / retry.
protected void	internal_prove()
protected void	internal_retry()
protected void	query()
void	retry()
void	run()
void	setListeners(jPrologServiceBroadcaster b, jPrologServiceBroadcaster r, jPrologServiceBroadcaster e, jPrologServiceBroadcaster s, jPrologServiceBroadcaster d)
protected boolean	waitForRetry()

Methods inherited from class ubc.cs.JLog.Foundation.jPrologServiceThread

broadcasted_stop, getPrologServices, isCurrentlyConsulting, printOutput, setAllowRelease, setStoppedListeners

Methods inherited from class java.lang.Thread

activeCount, checkAccess, clone, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

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

Field Detail

qinput

protected String qinput

beginq

protected jPrologServiceBroadcaster beginq

retryq

protected jPrologServiceBroadcaster retryq

endq

protected jPrologServiceBroadcaster endq

debugm

protected jPrologServiceBroadcaster debugm

prover

protected jProver prover

query

protected jPredicateTerms query

result

protected boolean result

retry

protected int retry

var_vector

protected jVariableVector var_vector

var_prebindings

protected Hashtable var_prebindings

result_exception

protected RuntimeException result_exception

Constructor Detail

jAPIQueryThread

public jAPIQueryThread(jPrologServices ps,
                       String qin)

jAPIQueryThread

public jAPIQueryThread(jPrologServices ps,
                       Hashtable bindings,
                       String qin)

Method Detail

setListeners

public void setListeners(jPrologServiceBroadcaster b,
                         jPrologServiceBroadcaster r,
                         jPrologServiceBroadcaster e,
                         jPrologServiceBroadcaster s,
                         jPrologServiceBroadcaster d)

retry

public void retry()

Specified by:

retry in class jRetryQueryThread

waitForRetry

protected boolean waitForRetry()

run

public void run()

Specified by:

run in interface Runnable

Overrides:

run in class Thread

query

protected void query()

internal_prove

protected void internal_prove()

internal_retry

protected void internal_retry()

getResultHashtable

public Hashtable getResultHashtable()

Returns a hashtable of the variable bindings, as a result of a sucessful query / retry.

Returns:

Returns a hashtable with all the variables in the query, and their bindings. Each key in the hashtable is a variable name, and the associated value is the jTerm the variable was bound to. Returns null if the query failed.

getResultException

public RuntimeException getResultException()

Returns the RuntimeException thrown by an unsucessful query / retry (e.g., UnknownPredicateException).

Returns:

Returns a RuntimeException if the query failed. Returns null if the query did not throw an exception.