| /* |
| * Copyright (c) 2018, 2019 Eike Stepper (Loehne, Germany) and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/epl-v10.html |
| * |
| * Contributors: |
| * Eike Stepper - initial API and implementation |
| */ |
| package org.eclipse.net4j.util.collection; |
| |
| import java.util.Collection; |
| import java.util.Iterator; |
| import java.util.NoSuchElementException; |
| |
| /** |
| * @author Eike Stepper |
| * @since 3.9 |
| */ |
| public class RoundRobinIterator<T> implements Iterator<T> |
| { |
| private final Collection<T> collection; |
| |
| private Iterator<T> delegate; |
| |
| public RoundRobinIterator(Collection<T> collection) |
| { |
| this.collection = collection; |
| if (!collection.isEmpty()) |
| { |
| delegate = collection.iterator(); |
| } |
| } |
| |
| @Override |
| public boolean hasNext() |
| { |
| return delegate != null; |
| } |
| |
| @Override |
| public T next() |
| { |
| if (delegate == null) |
| { |
| throw new NoSuchElementException(); |
| } |
| |
| if (!delegate.hasNext()) |
| { |
| delegate = collection.iterator(); |
| } |
| |
| return delegate.next(); |
| } |
| |
| @Override |
| public void remove() |
| { |
| throw new UnsupportedOperationException(); |
| } |
| } |