Package org.prolog4j

Class Query

java.lang.Object

org.prolog4j.Query

Direct Known Subclasses:

SWIPrologQuery, TuPrologQuery

public abstract class Query
extends Object

Represents a Prolog query. It is supposed to be created by Prover.query(String).

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Query(String goalPattern)	Creates a query object.

Method Summary

Modifier and Type	Method	Description
abstract Query	bind(int argument, Object value)	Binds a value to the specified argument of the goal.
abstract Query	bind(String variable, Object value)	Binds a value to the specified argument of the goal.
protected String	getGoal()	Returns the Prolog goal to be solved.
protected List<String>	getPlaceholderNames()	Returns a list with the name of the place holders in the query.
abstract <A> Solution<A>	solve(Object... actualArgs)	Solves the Prolog goal and returns an object using which the individual solutions can be iterated over.

Methods inherited from class java.lang.Object

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

Constructor Detail

Query

protected Query(String goalPattern)

Creates a query object.

Parameters:

goalPattern - the Prolog goal

Method Detail

getGoal

protected final String getGoal()

Returns the Prolog goal to be solved. The placeholders are removed from it, so it may differ from the original goal passed to the constructor.

Returns:

the Prolog goal to be solved

getPlaceholderNames

protected final List<String> getPlaceholderNames()

Returns a list with the name of the place holders in the query.

Returns:

the placeholderNames

solve

public abstract <A> Solution<A> solve(Object... actualArgs)

Solves the Prolog goal and returns an object using which the individual solutions can be iterated over. The actual arguments will be bound to the placeholders before solving the goal.

Type Parameters:

A - the type of an element of the solutions

Parameters:

actualArgs - the actual arguments of the goal

Returns:

an object for traversing the solutions

bind

public abstract Query bind(int argument,
                           Object value)

Binds a value to the specified argument of the goal. The argument is specified by its position. Numbering starts from zero.

The method returns the same query instance.

Parameters:

argument - the number of the argument of the goal

value - the value to be bound to the argument

Returns:

the same query instance

bind

public abstract Query bind(String variable,
                           Object value)

Binds a value to the specified argument of the goal. The argument is specified by its name.

Parameters:

variable - the name of the variable of the goal

value - the value to be bound to the variable

Returns:

the same query instance