com.github.thorbenkuck.netcom2.utility.AsynchronousIterator Maven / Gradle / Ivy

Go to download
package com.github.thorbenkuck.netcom2.utility;

import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Queue;

/**
 * This is an asynchronous Iterator. It works by making a copy of the specified collection,
 * and only working on that.
 *
 * @param  The type of the elements of this iterator
 * @version 1.0
 * @since 1.0
 */
final class AsynchronousIterator implements Iterator {

	private final Queue core;
	private final Collection source;
	private final boolean removeAllowed;
	private T currentElement;

	AsynchronousIterator(final Collection collection) {
		this(collection, false);
	}

	AsynchronousIterator(final Collection collection, boolean removeAllowed) {
		NetCom2Utils.parameterNotNull(collection);
		core = new LinkedList<>(collection);
		this.source = collection;
		this.removeAllowed = removeAllowed;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public boolean hasNext() {
		return core.peek() != null;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public T next() {
		currentElement = core.poll();
		return currentElement;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public void remove() {
		if (removeAllowed) {
			source.remove(currentElement);
		} else {
			throw new UnsupportedOperationException("remove");
		}
	}
}