/* * The MIT License (MIT) * * Copyright (c) 2017-2020 Yegor Bugayenko * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included * in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ package org.cactoos.iterator; import java.util.Collections; import java.util.Iterator; import java.util.LinkedList; import java.util.List; import org.cactoos.scalar.Sticky; import org.cactoos.scalar.Unchecked; /** * Shuffled iterator. * * <p>There is no thread-safety guarantee.</p> * * @param <T> Element type * @since 0.20 */ public final class Shuffled<T> implements Iterator<T> { /** * Shuffled scalar. */ private final Unchecked<Iterator<T>> scalar; /** * Ctor. * @param iterator The original iterator */ public Shuffled(final Iterator<T> iterator) { this.scalar = new Unchecked<>( new Sticky<>( () -> { final List<T> items = new LinkedList<>(); while (iterator.hasNext()) { items.add(iterator.next()); } Collections.shuffle(items); return items.iterator(); } ) ); } @Override public boolean hasNext() { return this.scalar.value().hasNext(); } @Override public T next() { return this.scalar.value().next(); } }