/*
    * The contents of this file are subject to the terms of the Common Development and
    * Distribution License (the License). You may not use this file except in compliance with the
    * License.
    *
    * You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
    * specific language governing permission and limitations under the License.
    *
    * When distributing Covered Software, include this CDDL Header Notice in each file and include
   * the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
   * Header, with the fields enclosed by brackets [] replaced by your own identifying
   * information: "Portions copyright [year] [name of copyright owner]".
   *
   * Copyright 2016 ForgeRock AS.
   */
  
  package org.forgerock.http.handler;
  
  import java.util.concurrent.TimeUnit;
  
  import org.forgerock.http.Filter;
  import org.forgerock.http.Handler;
  import org.forgerock.http.protocol.Request;
  import org.forgerock.http.protocol.Response;
  import org.forgerock.http.protocol.Status;
  import org.forgerock.services.context.Context;
  import org.forgerock.services.context.RootContext;
  import org.forgerock.util.promise.NeverThrowsException;
  import org.forgerock.util.promise.Promise;
  import org.openjdk.jmh.annotations.Benchmark;
  import org.openjdk.jmh.annotations.BenchmarkMode;
  import org.openjdk.jmh.annotations.Fork;
  import org.openjdk.jmh.annotations.Measurement;
  import org.openjdk.jmh.annotations.Mode;
  import org.openjdk.jmh.annotations.OutputTimeUnit;
  import org.openjdk.jmh.annotations.Scope;
  import org.openjdk.jmh.annotations.State;
  import org.openjdk.jmh.annotations.Threads;
  import org.openjdk.jmh.annotations.Warmup;
  import org.openjdk.jmh.runner.Runner;
  import org.openjdk.jmh.runner.RunnerException;
  import org.openjdk.jmh.runner.options.Options;
  import org.openjdk.jmh.runner.options.OptionsBuilder;
  
  @State(Scope.Thread)
  @BenchmarkMode(Mode.Throughput)
  @OutputTimeUnit(TimeUnit.MILLISECONDS)
  @Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
  @Measurement(iterations = 1, time = 2, timeUnit = TimeUnit.MINUTES)
  @Fork(1)
  @Threads(50)
  public class HandlersChainOfBenchmark {
  
      private Promise<Response, NeverThrowsException> OK_RESPONSE =
              Response.newResponsePromise(new Response(Status.OK));
  
      private Handler OK_HANDLER = new Handler() {
          @Override
          public Promise<Response, NeverThrowsException> handle(final Context context, final Request request) {
              return OK_RESPONSE;
          }
      };
  
      // use a non-final, non-static variable in order to prevent JVM optimization
      private double x = Math.PI;
  
      private final Filter PASS_THROUGH = new Filter() {
          @Override
          public Promise<Response, NeverThrowsException> filter(final Context context,
                  final Request request,
                  final Handler next) {
              // Prevent constant folding by the JVM
              if (x == Double.MAX_VALUE) { return null; }
              return next.handle(context, request);
          }
      };
      private Request REQUEST = new Request();
      private RootContext CONTEXT = new RootContext();
  
      private Handler original = Handlers.chainOf(OK_HANDLER, PASS_THROUGH, PASS_THROUGH, PASS_THROUGH, PASS_THROUGH, PASS_THROUGH);
  
      @Benchmark
      public Promise<Response, NeverThrowsException> testOriginalChainOf() {
          return original.handle(CONTEXT, REQUEST);
      }
  
      public static void main(String[] args) throws RunnerException {
          Options opt = new OptionsBuilder()
                  .include(HandlersChainOfBenchmark.class.getSimpleName())
                  .build();
  
          new Runner(opt).run();
      }
  
  }