NodeCachingLinkedListTest.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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
 *
 *      https://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 org.apache.commons.collections4.list;

import java.util.Arrays;
import java.util.LinkedList;

import org.junit.jupiter.api.Test;

/**
 * Test class for NodeCachingLinkedList, a performance optimized LinkedList.
 */
public class NodeCachingLinkedListTest<E> extends AbstractLinkedListTest<E> {

    public static void compareSpeed() {
        final NodeCachingLinkedList<Object> ncll = new NodeCachingLinkedList<>();
        final LinkedList<Object> ll = new LinkedList<>();

        final Object o1 = new Object();
        final Object o2 = new Object();

        final int loopCount = 4000000;

        System.out.println("Testing relative execution time of commonly-used methods...");

        long startTime = System.currentTimeMillis();
        for (int x = loopCount; x > 0; x--) {
            // unrolled a few times to minimize effect of loop
            ll.addFirst(o1);
            ll.addLast(o2);
            ll.removeFirst();
            ll.removeLast();
            ll.add(o1);
            ll.remove(0);
            //
            ll.addFirst(o1);
            ll.addLast(o2);
            ll.removeFirst();
            ll.removeLast();
            ll.add(o1);
            ll.remove(0);
            //
            ll.addFirst(o1);
            ll.addLast(o2);
            ll.removeFirst();
            ll.removeLast();
            ll.add(o1);
            ll.remove(0);
        }
        long endTime = System.currentTimeMillis();
        System.out.println("Time with LinkedList: " + (endTime - startTime) + " ms");

        startTime = System.currentTimeMillis();
        for (int x = loopCount; x > 0; x--) {
            ncll.addFirst(o1);
            ncll.addLast(o2);
            ncll.removeFirst();
            ncll.removeLast();
            ncll.add(o1);
            ncll.remove(0);
            //
            ncll.addFirst(o1);
            ncll.addLast(o2);
            ncll.removeFirst();
            ncll.removeLast();
            ncll.add(o1);
            ncll.remove(0);
            //
            ncll.addFirst(o1);
            ncll.addLast(o2);
            ncll.removeFirst();
            ncll.removeLast();
            ncll.add(o1);
            ncll.remove(0);
        }
        endTime = System.currentTimeMillis();
        System.out.println("Time with NodeCachingLinkedList: " + (endTime - startTime) + " ms");

    }

    /**
     * {@inheritDoc}
     */
    @Override
    public NodeCachingLinkedList<E> getCollection() {
        return (NodeCachingLinkedList<E>) super.getCollection();
    }

    @Override
    public String getCompatibilityVersion() {
        return "4";
    }

    @Override
    public NodeCachingLinkedList<E> makeObject() {
        return new NodeCachingLinkedList<>();
    }

//    void testCreate() throws Exception {
//        resetEmpty();
//        writeExternalFormToDisk((java.io.Serializable) getCollection(),
//           "src/test/resources/data/test/NodeCachingLinkedList.emptyCollection.version4.obj");
//        resetFull();
//        writeExternalFormToDisk((java.io.Serializable) getCollection(),
//            "src/test/resources/data/test/NodeCachingLinkedList.fullCollection.version4.obj");
//    }

    @Test
    @SuppressWarnings("unchecked")
    void testShrinkCache() {
        if (!isRemoveSupported() || !isAddSupported()) {
            return;
        }
        resetEmpty();
        final NodeCachingLinkedList<E> list = getCollection();

        list.addAll(Arrays.asList((E[]) new String[] { "1", "2", "3", "4" }));
        list.removeAllNodes(); // Will dump all 4 elements into cache
        list.setMaximumCacheSize(2); // shrink cache
        list.addAll(Arrays.asList((E[]) new String[] { "1", "2", "3", "4" }));
        checkNodes();
        list.removeNode(list.getNode(0, false)); // no room in cache
        list.removeNode(list.getNode(0, false));
        list.removeNode(list.getNode(0, false));
        checkNodes();
        list.addAll(Arrays.asList((E[]) new String[] { "1", "2", "3", "4" }));
        checkNodes();
    }
}