/*
 * Copyright (c) 2014, Oracle America, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  * Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 *  * Neither the name of Oracle nor the names of its contributors may be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.openjdk.jol.samples;

import org.openjdk.jol.info.GraphLayout;
import org.openjdk.jol.vm.VM;

import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;

import static java.lang.System.out;

/**
 * @author Aleksey Shipilev
 */
public class JOLSample_16_AL_LL {

    /*
     * The example of traversing the reachability graphs.
     *
     * In addition to introspecting the object internals, we can also
     * see the object externals, that is, the objects referenced from the
     * object in question. There are multiple ways to illustrate this,
     * the summary table seems to work well.
     *
     * In this example, you can clearly see the difference between
     * the shadow heap (i.e. space taken by the reachable objects)
     * for ArrayList and LinkedList.
     *
     * When several roots are handed over to JOL, it tracks the objects reachable
     * from either root, and also avoids double-counting.
     */

    public static void main(String[] args) throws Exception {
        out.println(VM.current().details());

        ArrayList<Integer> al = new ArrayList<Integer>();
        LinkedList<Integer> ll = new LinkedList<Integer>();

        for (int i = 0; i < 1000; i++) {
            Integer io = i; // box once
            al.add(io);
            ll.add(io);
        }

        al.trimToSize();

        PrintWriter pw = new PrintWriter(out);
        pw.println(GraphLayout.parseInstance(al).toFootprint());
        pw.println(GraphLayout.parseInstance(ll).toFootprint());
        pw.println(GraphLayout.parseInstance(al, ll).toFootprint());
        pw.close();
    }

}