PrologQueryIterator.java
/*
* #%L
* prolobjectlink-jpi
* %%
* Copyright (C) 2019 Prolobjectlink Project
* %%
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* THE SOFTWARE.
* #L%
*/
package io.github.prolobjectlink.prolog;
import java.util.Collection;
import java.util.Iterator;
import java.util.NoSuchElementException;
/**
* Iterator class implementation for Prolog Query
*
* @author Jose Zalacain
* @since 1.0
*/
final class PrologQueryIterator extends AbstractIterator<Collection<PrologTerm>>
implements Iterator<Collection<PrologTerm>> {
private final PrologQuery query;
/**
* Create a new query iterator over given PrologQuery.
*
* @param query PrologQuery to iterate
*/
PrologQueryIterator(PrologQuery query) {
this.query = query;
}
/**
* True if the current Prolog query has more solution, false if not has more
* solution
*/
public boolean hasNext() {
return query.hasMoreSolutions();
}
/**
* Next Prolog solution terms
*/
public Collection<PrologTerm> next() {
if (!query.hasMoreSolutions()) {
throw new NoSuchElementException();
}
return query.nextVariablesSolution().values();
}
/**
* Skip the next solution invoking next solution method
*/
@Override
public void remove() {
query.nextSolution();
}
}