1 /* 2 * #%L 3 * prolobjectlink-jpi 4 * %% 5 * Copyright (C) 2019 Prolobjectlink Project 6 * %% 7 * Permission is hereby granted, free of charge, to any person obtaining a copy 8 * of this software and associated documentation files (the "Software"), to deal 9 * in the Software without restriction, including without limitation the rights 10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 11 * copies of the Software, and to permit persons to whom the Software is 12 * furnished to do so, subject to the following conditions: 13 * 14 * The above copyright notice and this permission notice shall be included in 15 * all copies or substantial portions of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 20 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 23 * THE SOFTWARE. 24 * #L% 25 */ 26 package io.github.prolobjectlink.prolog; 27 28 import java.util.Collection; 29 import java.util.Iterator; 30 import java.util.NoSuchElementException; 31 32 /** 33 * Iterator class implementation for Prolog Query 34 * 35 * @author Jose Zalacain 36 * @since 1.0 37 */ 38 final class PrologQueryIterator extends AbstractIterator<Collection<PrologTerm>> 39 implements Iterator<Collection<PrologTerm>> { 40 41 private final PrologQuery query; 42 43 /** 44 * Create a new query iterator over given PrologQuery. 45 * 46 * @param query PrologQuery to iterate 47 */ 48 PrologQueryIterator(PrologQuery query) { 49 this.query = query; 50 } 51 52 /** 53 * True if the current Prolog query has more solution, false if not has more 54 * solution 55 */ 56 public boolean hasNext() { 57 return query.hasMoreSolutions(); 58 } 59 60 /** 61 * Next Prolog solution terms 62 */ 63 public Collection<PrologTerm> next() { 64 if (!query.hasMoreSolutions()) { 65 throw new NoSuchElementException(); 66 } 67 return query.nextVariablesSolution().values(); 68 } 69 70 /** 71 * Skip the next solution invoking next solution method 72 */ 73 @Override 74 public void remove() { 75 query.nextSolution(); 76 } 77 78 }