com.ugos.JIProlog.engine
Class JIPQuery

java.lang.Object
  |
  +--com.ugos.JIProlog.engine.JIPQuery

All Implemented Interfaces:

java.io.Serializable

public class JIPQuery

extends java.lang.Object

implements java.io.Serializable

JIPQuery wraps a single synchronous query.
By asyncronous call it is intended a call to prolog interpreter that runs in a separate thread and notify for solutions all event listeners
. By syncronous call it is intended a call to prolog interpreter that runs in the same thread and exit when a solution is found
. An asyncronous, more powerful, management of the prolog interpreter see JIPEngine.
For more information see the section "How to make a synchronous call to prolog interpreter"

Since:

2.0 Home Page: http://www.ugosweb.com/jiprolog

Version:

2.0

Author:

Ugo Chirico 2002

See Also:

JIPEngine, Serialized Form

Method Summary

void	close() Closes the query
boolean	hasMoreChoicePoints() Returns true if the query has more choice points on backtracking.
boolean	isClosed() Returns true if the query is closed.
JIPTerm	nextSolution() Searches for another solution.

Methods inherited from class java.lang.Object

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

Method Detail

nextSolution

public final JIPTerm nextSolution()
                           throws JIPQueryClosedException

Searches for another solution. When a solution is found it returns the corresponding JIPTerm object. If there are no more solutions it returns null.
Raises a JIPQueryClosedException if called again after it has returned null.

Returns:

next solution found or null if there are no more solution.

Throws:

JIPQueryClosedException

See Also:

JIPTerm

hasMoreChoicePoints

public final boolean hasMoreChoicePoints()

Returns true if the query has more choice points on backtracking.

Returns:

true if the query has more choice points or if nextSolution has not been colled yet, false otherwise.

isClosed

public final boolean isClosed()

Returns true if the query is closed.

Returns:

true if the query is closed, false otherwise.

close

public final void close()

Closes the query