/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

/*

 *

 */

package bench.serial;

import bench.Benchmark;

import java.io.ObjectInputStream;

import java.io.ObjectOutputStream;

import java.io.Serializable;

/**

 * Benchmark for testing speed of writes and reads of a tree of replaceable

 * objects.

 */

public class ReplaceTrees implements Benchmark {

    static class Node implements Serializable {

        Object parent, left, right;

        Node(Object parent, Object left, Object right) {

            this.parent = parent;

            this.left = left;

            this.right = right;

        }

        Node(Object parent, int depth) {

            this.parent = parent;

            if (depth > 0) {

                left = new Node(this, depth - 1);

                right = new Node(this, depth - 1);

            }

        }

        Object writeReplace() {

            return new RepNode(parent, left, right);

        }

    }

    static class RepNode implements Serializable {

        Object parent, left, right;

        RepNode(Object parent, Object left, Object right) {

            this.parent = parent;

            this.left = left;

            this.right = right;

        }

        Object readResolve() {

            return new Node(parent, left, right);

        }

    }

    /**

     * Write and read a tree of replaceable objects from a stream.  The

     * benchmark is run in batches: each "batch" consists of a fixed number of

     * read/write cycles, and the stream is flushed (and underlying stream

     * buffer cleared) in between each batch.

     * Arguments: <tree depth> <# batches> <# cycles per batch>

     */

    public long run(String[] args) throws Exception {

        int depth = Integer.parseInt(args[0]);

        int nbatches = Integer.parseInt(args[1]);

        int ncycles = Integer.parseInt(args[2]);

        Node[] trees = genTrees(depth, ncycles);

        StreamBuffer sbuf = new StreamBuffer();

        ObjectOutputStream oout =

            new ObjectOutputStream(sbuf.getOutputStream());

        ObjectInputStream oin =

            new ObjectInputStream(sbuf.getInputStream());

        doReps(oout, oin, sbuf, trees, 1);      // warmup

        long start = System.currentTimeMillis();

        doReps(oout, oin, sbuf, trees, nbatches);

        return System.currentTimeMillis() - start;

    }

    /**

     * Generate object trees.

     */

    Node[] genTrees(int depth, int ntrees) {

        Node[] trees = new Node[ntrees];

        for (int i = 0; i < ntrees; i++) {

            trees[i] = new Node(null, depth);

        }

        return trees;

    }

    /**

     * Run benchmark for given number of batches, with each batch containing

     * the given number of cycles.

     */

    void doReps(ObjectOutputStream oout, ObjectInputStream oin,

                StreamBuffer sbuf, Node[] trees, int nbatches)

        throws Exception

    {

        int ncycles = trees.length;

        for (int i = 0; i < nbatches; i++) {

            sbuf.reset();

            oout.reset();

            for (int j = 0; j < ncycles; j++) {

                oout.writeObject(trees[j]);

            }

            oout.flush();

            for (int j = 0; j < ncycles; j++) {

                oin.readObject();

            }

        }

    }

}