ReplaceTrees.java

/*
 * Copyright (c) 1999, 2008, Oracle and/or its affiliates. All rights reserved.
 * 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.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();
            }
        }
    }
}