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    1   /*
    2    * Copyright 2009 Red Hat, Inc.
    3    *
    4    * Red Hat licenses this file to you under the Apache License, version 2.0
    5    * (the "License"); you may not use this file except in compliance with the
    6    * 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   * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
    24   * @author <a href="http://gleamynode.net/">Trustin Lee</a>
    25   *
    26   * @version $Rev: 2080 $, $Date: 2010-01-26 18:04:19 +0900 (Tue, 26 Jan 2010) $
    27   */
    28  public class AdaptiveReceiveBufferSizePredictorFactory implements
    29          ReceiveBufferSizePredictorFactory {
    30
    31      private final int minimum;
    32      private final int initial;
    33      private final int maximum;
    34
    35      /**
    36       * Creates a new factory with the default parameters.  With the default
    37       * parameters, the expected buffer size starts from {@code 1024}, does not
    38       * go down below {@code 64}, and does not go up above {@code 65536}.
    39       */
    40      public AdaptiveReceiveBufferSizePredictorFactory() {
    41          this(AdaptiveReceiveBufferSizePredictor.DEFAULT_MINIMUM,
    42                  AdaptiveReceiveBufferSizePredictor.DEFAULT_INITIAL,
    43                  AdaptiveReceiveBufferSizePredictor.DEFAULT_MAXIMUM);
    44      }
    45
    46      /**
    47       * Creates a new factory with the specified parameters.
    48       *
    49       * @param minimum  the inclusive lower bound of the expected buffer size
    50       * @param initial  the initial buffer size when no feed back was received
    51       * @param maximum  the inclusive upper bound of the expected buffer size
    52       */
    53      public AdaptiveReceiveBufferSizePredictorFactory(int minimum, int initial, int maximum) {
    54          if (minimum <= 0) {
    55              throw new IllegalArgumentException("minimum: " + minimum);
    56          }
    57          if (initial < minimum) {
    58              throw new IllegalArgumentException("initial: " + initial);
    59          }
    60          if (maximum < initial) {
    61              throw new IllegalArgumentException("maximum: " + maximum);
    62          }
    63
    64          this.minimum = minimum;
    65          this.initial = initial;
    66          this.maximum = maximum;
    67      }
    68
    69      public ReceiveBufferSizePredictor getPredictor() throws Exception {
    70          return new AdaptiveReceiveBufferSizePredictor(minimum, initial, maximum);
    71      }
    72  }