com.github.housepower.jdbc.profiling.Profiler

Profiler.java

package com.github.housepower.jdbc.profiling;

public class Profiler {
  public class ElapsedTime {
    private long elapsedTimeMillis;
    private long elapsedTimeDeltaMillis;

    public long getElapsedTimeMillis() { return elapsedTimeMillis; }
    public long getElapsedTimeDeltaMillis() { return elapsedTimeDeltaMillis; }

    public ElapsedTime(long etMillis, long etDeltaMillis) {
      elapsedTimeMillis = etMillis;
      elapsedTimeDeltaMillis = etDeltaMillis;
    }
  }

  private static final long MEGABYTE = 1024L * 1024L;

  public static long bytesToMegabytes(long bytes) {
    return bytes / MEGABYTE;
  }

  public static String fixedLengthString(String string, int length) {
    return String.format("%1$"+length+ "s", string);
  }


  long startTimeMillis;
  long lastEventTimeMillis;
  Runtime runtime;

  private static final Profiler _instance = new Profiler();

  public static synchronized Profiler getInstance() {
    return _instance;
  }

  private Profiler() {
    startTimeMillis = System.currentTimeMillis();
    lastEventTimeMillis = startTimeMillis;
    runtime = Runtime.getRuntime();
  }

  public void start() {
    System.out.println("Profiler started");
  }

  private ElapsedTime getElapsedTime() {
    long now = System.currentTimeMillis();
    long elapsedMillis = now - startTimeMillis;
    long elapsedDeltaMillis = now - lastEventTimeMillis;
    lastEventTimeMillis = now;
    return new ElapsedTime(elapsedMillis, elapsedDeltaMillis);
  }

  public void logStat(long percentComplete, int runGc) {
    if (runGc == 1) {
      runtime.gc();
    }
    // Calculate the used memory
    long totalMemory = runtime.totalMemory();
    long memory = totalMemory - runtime.freeMemory();

    ElapsedTime elapsedTime = getElapsedTime();
    long elapsedMillis = elapsedTime.getElapsedTimeMillis();
    long elapsedDeltaMillis = elapsedTime.getElapsedTimeDeltaMillis();

    String percentCompleteStr = fixedLengthString(String.valueOf(percentComplete), 3) + "%";
    String totalMemoryStr = fixedLengthString(String.valueOf(bytesToMegabytes(totalMemory)), 5);
    String usedMemoryStr = fixedLengthString(String.valueOf(bytesToMegabytes(memory)), 5);
    String totalElapsedMillisStr = fixedLengthString(String.valueOf(elapsedMillis), 6);
    String millisPassedFromLastLogStr = fixedLengthString(String.valueOf(elapsedDeltaMillis), 6);
    System.out.println(percentCompleteStr + " Total memory (MB): " + totalMemoryStr + ", used memory (MB): "
        + usedMemoryStr + ", time elapsed: " + totalElapsedMillisStr + "(+" + millisPassedFromLastLogStr + " ms)");
  }
}