session-android/src/org/thoughtcrime/securesms/util/Stopwatch.java

package org.thoughtcrime.securesms.util;

import android.support.annotation.NonNull;

import org.thoughtcrime.securesms.logging.Log;

import java.util.LinkedList;
import java.util.List;

public class Stopwatch {

  private final long        startTime;
  private final String      title;
  private final List<Split> splits;

  public Stopwatch(@NonNull String title) {
    this.startTime = System.currentTimeMillis();
    this.title     = title;
    this.splits    = new LinkedList<>();
  }

  public void split(@NonNull String label) {
    splits.add(new Split(System.currentTimeMillis(), label));
  }

  public void stop(@NonNull String tag) {
    StringBuilder out = new StringBuilder();
    out.append("[").append(title).append("] ");

    if (splits.size() > 0) {
      out.append(splits.get(0).label).append(": ");
      out.append(splits.get(0).time - startTime);
      out.append("  ");
    }

    if (splits.size() > 1) {
      for (int i = 1; i < splits.size(); i++) {
        out.append(splits.get(i).label).append(": ");
        out.append(splits.get(i).time - splits.get(i - 1).time);
        out.append("  ");
      }

      out.append("total: ").append(splits.get(splits.size() - 1).time - startTime);
    }

    Log.d(tag, out.toString());
  }

  private static class Split {
    final long   time;
    final String label;

    Split(long time, String label) {
      this.time  = time;
      this.label = label;
    }
  }
}