com.github.sirikid.iterators.SingletonIterator Maven / Gradle / Ivy

Go to download
/*
 * Copyright (c) 2015-2016, Ivan Sokolov. All rights reserved.
 * This code is licensed under MIT license (see LICENSE for details)
 */

package com.github.sirikid.iterators;

import java.util.Iterator;
import java.util.NoSuchElementException;
import javax.annotation.Nullable;

/**
 * Iterator, that contains only one element.
 *
 * @author Ivan Sokolov
 * @version 1.0.0
 * @param  type of element
 * @see SingletonSpliterator
 * @since 1.0.0
 */

public class SingletonIterator implements Iterator {
	@Nullable private final T value;
	private boolean alreadyUsed;

	/**
	 * Sole constructor.
	 *
	 * @param value the value to be in iterator
	 */
	public SingletonIterator(@Nullable T value) {
		this.value = value;
		alreadyUsed = false;
	}

	/** {@inheritDoc} */
	@Override
	public boolean hasNext() {
		return !alreadyUsed;
	}

	/** {@inheritDoc} */
	@Nullable
	@Override
	public T next() {
		if (!hasNext()) throw new NoSuchElementException();
//		final T result = value;
//		value = null; // XXX Shall I assign null for proper GC working or retain this link?
		alreadyUsed = true;
//		return result;
		return value;
	}
}