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    1   /*
    2    * Copyright 2012 The Netty Project
    3    *
    4    * The Netty Project licenses this file to you under the Apache License,
    5    * version 2.0 (the "License"); you may not use this file except in compliance
    6    * with the License. You may obtain a copy of the License at:
    7    *
    8    *   http://www.apache.org/licenses/LICENSE-2.0
    9    *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
    12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
    13   * License for the specific language governing permissions and limitations
    14   * under the License.
    15   */
    16  package org.jboss.netty.channel;
    17
    18
    19  /**
    20   * The {@link ReceiveBufferSizePredictorFactory} that creates a new
    21   * {@link AdaptiveReceiveBufferSizePredictor}.
    22   */
    23  public class AdaptiveReceiveBufferSizePredictorFactory implements
    24          ReceiveBufferSizePredictorFactory {
    25
    26      private final int minimum;
    27      private final int initial;
    28      private final int maximum;
    29
    30      /**
    31       * Creates a new factory with the default parameters.  With the default
    32       * parameters, the expected buffer size starts from {@code 1024}, does not
    33       * go down below {@code 64}, and does not go up above {@code 65536}.
    34       */
    35      public AdaptiveReceiveBufferSizePredictorFactory() {
    36          this(AdaptiveReceiveBufferSizePredictor.DEFAULT_MINIMUM,
    37                  AdaptiveReceiveBufferSizePredictor.DEFAULT_INITIAL,
    38                  AdaptiveReceiveBufferSizePredictor.DEFAULT_MAXIMUM);
    39      }
    40
    41      /**
    42       * Creates a new factory with the specified parameters.
    43       *
    44       * @param minimum  the inclusive lower bound of the expected buffer size
    45       * @param initial  the initial buffer size when no feed back was received
    46       * @param maximum  the inclusive upper bound of the expected buffer size
    47       */
    48      public AdaptiveReceiveBufferSizePredictorFactory(int minimum, int initial, int maximum) {
    49          if (minimum <= 0) {
    50              throw new IllegalArgumentException("minimum: " + minimum);
    51          }
    52          if (initial < minimum) {
    53              throw new IllegalArgumentException("initial: " + initial);
    54          }
    55          if (maximum < initial) {
    56              throw new IllegalArgumentException("maximum: " + maximum);
    57          }
    58
    59          this.minimum = minimum;
    60          this.initial = initial;
    61          this.maximum = maximum;
    62      }
    63
    64      public ReceiveBufferSizePredictor getPredictor() throws Exception {
    65          return new AdaptiveReceiveBufferSizePredictor(minimum, initial, maximum);
    66      }
    67  }