001/*
002 * Copyright (c) 2015-2020, Oracle and/or its affiliates. All rights reserved.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.tribuo.math.la;
018
019import java.util.Iterator;
020
021/**
022 * A {@link Comparable} {@link Iterator} over {@link VectorTuple}s.
023 * <p>
024 * The comparison is based on the indices, not on the values.
025 * To use the comparator .next must have been called once.
026 */
027public interface VectorIterator extends Iterator<VectorTuple>, Comparable<VectorIterator> {
028
029    /**
030     * Gets the reference to the VectorTuple this iterator updates.
031     * @return The VectorTuple reference.
032     */
033    public VectorTuple getReference();
034
035    @Override
036    public default int compareTo(VectorIterator o) {
037        VectorTuple ours = getReference();
038        VectorTuple other = o.getReference();
039        return Integer.compare(ours.index, other.index);
040    }
041
042}