/*
 *  This file is part of the Jikes RVM project (http://jikesrvm.org).
 *
 *  This file is licensed to You under the Eclipse Public License (EPL);
 *  You may not use this file except in compliance with the License. You
 *  may obtain a copy of the License at
 *
 *      http://www.opensource.org/licenses/eclipse-1.0.php
 *
 *  See the COPYRIGHT.txt file distributed with this work for information
 *  regarding copyright ownership.
 */
package org.mmtk.utility.statistics;

import org.vmmagic.pragma.*;

/**
 * This class implements a simple counter of events of different sizes
 * (eg object allocations, where total number of objects and total
 * volume of objects would be counted).<p>
 *
 * The counter is trivially composed from two event counters (one for
 * counting the number of events, the other for counting the volume).
 */
@Uninterruptible
public class SizeCounter {

  /****************************************************************************
   *
   * Instance variables
   */

  /**
   *
   */
  private final EventCounter units;
  private final EventCounter volume;

  /****************************************************************************
   *
   * Initialization
   */

  /**
   * Constructor
   *
   * @param name The name to be associated with this counter
   */
  public SizeCounter(String name) {
    this(name, true, false);
  }

  /**
   * Constructor
   *
   * @param name The name to be associated with this counter
   * @param start True if this counter is to be implicitly started
   * when <code>startAll()</code> is called (otherwise the counter
   * must be explicitly started).
   */
  public SizeCounter(String name, boolean start) {
    this(name, start, false);
  }

  /**
   * Constructor
   *
   * @param name The name to be associated with this counter
   * @param start True if this counter is to be implicitly started
   * when <code>startAll()</code> is called (otherwise the counter
   * must be explicitly started).
   * @param mergephases True if this counter does not separately
   * report GC and Mutator phases.
   */
  public SizeCounter(String name, boolean start, boolean mergephases) {
    units = new EventCounter(name, start, mergephases);
    volume = new EventCounter(name + "Volume", start, mergephases);
  }

  /****************************************************************************
   *
   * Counter-specific methods
   */

  /**
   * Increment the event counter by <code>value</code>
   *
   * @param value The amount by which the counter should be incremented.
   */
  public void inc(int value) {
    units.inc();
    volume.inc(value);
  }

  /****************************************************************************
   *
   * Generic counter control methods: start, stop, print etc
   */

  /**
   * Start this counter
   */
  public void start() {
    units.start();
    volume.start();
  }

  /**
   * Stop this counter
   */
  public void stop() {
    units.stop();
    volume.stop();
  }

  /**
   * Print current (mid-phase) units
   */
  public void printCurrentUnits() {
    units.printCurrent();
  }

  /**
   * Print (mid-phase) volume
   */
  public void printCurrentVolume() {
    volume.printCurrent();
  }

  /**
   * Print units
   */
  public void printUnits() {
    units.printTotal();
  }

  /**
   * Print volume
   */
  public void printVolume() {
    volume.printTotal();
  }
}