PerfListener.java

/*
 * This file provided by Facebook is for non-commercial testing and evaluation
 * purposes only.  Facebook reserves all rights not expressly granted.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package com.facebook.fresco.sample.instrumentation;

/**
 * Collects wait times and holds image loading stats.
 */
public class PerfListener {
  private long mSumOfWaitTime;
  private long mStartedRequests;
  private long mSuccessfulRequests;
  private long mCancelledRequests;
  private long mFailedRequests;

  public PerfListener() {
    mSumOfWaitTime = 0;
    mStartedRequests = 0;
    mSuccessfulRequests = 0;
    mCancelledRequests = 0;
    mFailedRequests = 0;
  }

  /**
   * Called whenever image request finishes successfully, that is whenever final image is set.
   */
  public void reportSuccess(long waitTime) {
    mSumOfWaitTime += waitTime;
    mSuccessfulRequests++;
  }

  /**
   * Called whenever image request fails, that is whenever failure drawable is set.
   */
  public void reportFailure(long waitTime) {
    mSumOfWaitTime += waitTime;
    mFailedRequests++;
  }

  /**
   * Called whenever image request is cancelled, that is whenever image view is reused without
   * setting final image first
   */
  public void reportCancellation(long waitTime) {
    mSumOfWaitTime += waitTime;
    mCancelledRequests++;
  }

  /**
   * Called whenver new request is started.
   */
  public void reportStart() {
    mStartedRequests++;
  }

  /**
   * @return average wait time, that is sum of reported wait times divided by number of completed
   *   requests
   */
  public long getAverageWaitTime() {
    final long completedRequests = getCompletedRequests();
    return completedRequests > 0 ? mSumOfWaitTime / completedRequests : 0;
  }

  /**
   * @return difference between number of started requests and number of completed requests
   */
  public long getOutstandingRequests() {
    return mStartedRequests - getCompletedRequests();
  }

  /**
   * @return number of cancelled requests
   */
  public long getCancelledRequests() {
    return mCancelledRequests;
  }

  /**
   * @return number of completed requests, either by seting final image, failure or cancellation
   */
  public long getCompletedRequests() {
    return mSuccessfulRequests + mCancelledRequests + mFailedRequests;
  }
}