/*
 * Copyright 2013-present Facebook, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License. You may obtain
 * a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */

package com.facebook.buck.util.concurrent;

import com.google.common.base.Preconditions;

/** Amalgamation of parameters that control how many jobs we can run at once. */
public class ConcurrencyLimit {

  /** Considered as number of build threads that are available for extensive computations. */
  public final int threadLimit;

  public final ResourceAllocationFairness resourceAllocationFairness;
  /**
   * Number of threads that Buck can manage and use them as worker threads. This number includes
   * {@link ConcurrencyLimit#threadLimit} value. The rest of the threads may be used for lightweight
   * tasks, I/O blocking tasks, etc.
   */
  public final int managedThreadCount;
  /** Default resource amounts that job would require. */
  public final ResourceAmounts defaultAmounts;
  /** Maximum resource amounts that are available on the system for all jobs to share. */
  public final ResourceAmounts maximumAmounts;

  public ConcurrencyLimit(
      int threadLimit,
      ResourceAllocationFairness resourceAllocationFairness,
      int managedThreadCount,
      ResourceAmounts defaultAmounts,
      ResourceAmounts maximumAmounts) {
    this.threadLimit = threadLimit;
    this.resourceAllocationFairness = resourceAllocationFairness;
    this.managedThreadCount = managedThreadCount;
    this.defaultAmounts = defaultAmounts;
    this.maximumAmounts = maximumAmounts;

    Preconditions.checkArgument(
        threadLimit <= managedThreadCount,
        "threadLimit (%d) should be <= managedThreadCount (%d)",
        threadLimit,
        managedThreadCount);
  }
}