it.unimi.dsi.fastutil.objects.AbstractObjectBidirectionalIterator Maven / Gradle / Ivy
/*
* Copyright (C) 2002-2017 Sebastiano Vigna
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package it.unimi.dsi.fastutil.objects;
/** An abstract class facilitating the creation of type-specific {@linkplain it.unimi.dsi.fastutil.BidirectionalIterator bidirectional iterators}.
*
* To create a type-specific bidirectional iterator, besides what is needed
* for an iterator you need both a method returning the previous element as
* primitive type and a method returning the previous element as an
* object. However, if you inherit from this class you need just one (anyone).
*
*
This class implements also a trivial version of {@link #back(int)} that
* uses type-specific methods.
*/
public abstract class AbstractObjectBidirectionalIterator extends AbstractObjectIterator implements ObjectBidirectionalIterator {
protected AbstractObjectBidirectionalIterator() {}
/** {@inheritDoc}
* This implemntation iterates the type-specific version of {@link #previous()} for
* at most {@code n} times, stopping if {@link #hasPrevious()} becomes false.
*
* @param n the number of elements to skip backwards.
* @return the number of elements actually skipped.
* @see #previous()
*/
@Override
public int back(final int n) {
int i = n;
while(i-- != 0 && hasPrevious()) previous();
return n - i - 1;
}
}