content: /*
   * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  package java.util;
  
  import java.util.function.IntConsumer;
  import java.util.stream.Collector;
  
  /**
   * A state object for collecting statistics such as count, min, max, sum, and
   * average.
   *
   * <p>This class is designed to work with (though does not require)
   * {@linkplain java.util.stream streams}. For example, you can compute
   * summary statistics on a stream of ints with:
   * <pre> {@code
   * IntSummaryStatistics stats = intStream.collect(IntSummaryStatistics::new,
   *                                                IntSummaryStatistics::accept,
   *                                                IntSummaryStatistics::combine);
   * }</pre>
   *
   * <p>{@code IntSummaryStatistics} can be used as a
   * {@linkplain java.util.stream.Stream#collect(Collector) reduction}
   * target for a {@linkplain java.util.stream.Stream stream}. For example:
   *
   * <pre> {@code
   * IntSummaryStatistics stats = people.stream()
   *                                    .collect(Collectors.summarizingInt(Person::getDependents));
   *}</pre>
   *
   * This computes, in a single pass, the count of people, as well as the minimum,
   * maximum, sum, and average of their number of dependents.
   *
   * @implNote This implementation is not thread safe. However, it is safe to use
   * {@link java.util.stream.Collectors#summarizingInt(java.util.function.ToIntFunction)
   * Collectors.toIntStatistics()} on a parallel stream, because the parallel
   * implementation of {@link java.util.stream.Stream#collect Stream.collect()}
   * provides the necessary partitioning, isolation, and merging of results for
   * safe and efficient parallel execution.
   *
   * <p>This implementation does not check for overflow of the sum.
   * @since 1.8
   */
  public class IntSummaryStatistics implements IntConsumer {
      private long count;
      private long sum;
      private int min = Integer.MAX_VALUE;
      private int max = Integer.MIN_VALUE;
  
      /**
       * Construct an empty instance with zero count, zero sum,
       * {@code Integer.MAX_VALUE} min, {@code Integer.MIN_VALUE} max and zero
       * average.
       */
      public IntSummaryStatistics() { }
  
      /**
       * Records a new value into the summary information
       *
       * @param value the input value
       */
      @Override
      public void accept(int value) {
          ++count;
          sum += value;
          min = Math.min(min, value);
          max = Math.max(max, value);
      }
  
      /**
       * Combines the state of another {@code IntSummaryStatistics} into this one.
       *
       * @param other another {@code IntSummaryStatistics}
       * @throws NullPointerException if {@code other} is null
       */
      public void combine(IntSummaryStatistics other) {
          count += other.count;
          sum += other.sum;
          min = Math.min(min, other.min);
          max = Math.max(max, other.max);
      }
  
      /**
       * Returns the count of values recorded.
       *
       * @return the count of values
       */
      public final long getCount() {
          return count;
      }
  
      /**
       * Returns the sum of values recorded, or zero if no values have been
       * recorded.
       *
       * @return the sum of values, or zero if none
       */
      public final long getSum() {
          return sum;
      }
  
      /**
       * Returns the minimum value recorded, or {@code Integer.MAX_VALUE} if no
       * values have been recorded.
       *
       * @return the minimum value, or {@code Integer.MAX_VALUE} if none
       */
      public final int getMin() {
          return min;
      }
  
      /**
       * Returns the maximum value recorded, or {@code Integer.MIN_VALUE} if no
       * values have been recorded.
       *
       * @return the maximum value, or {@code Integer.MIN_VALUE} if none
       */
      public final int getMax() {
          return max;
      }
  
      /**
       * Returns the arithmetic mean of values recorded, or zero if no values have been
       * recorded.
       *
       * @return the arithmetic mean of values, or zero if none
       */
      public final double getAverage() {
          return getCount() > 0 ? (double) getSum() / getCount() : 0.0d;
      }
  
      @Override
      /**
       * {@inheritDoc}
       *
       * Returns a non-empty string representation of this object suitable for
       * debugging. The exact presentation format is unspecified and may vary
       * between implementations and versions.
       */
      public String toString() {
          return String.format(
              "%s{count=%d, sum=%d, min=%d, average=%f, max=%d}",
              this.getClass().getSimpleName(),
              getCount(),
              getSum(),
              getMin(),
              getAverage(),
              getMax());
      }
  }
  