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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.buffer;
    17
    18  import java.nio.ByteBuffer;
    19  import java.nio.ByteOrder;
    20
    21  /**
    22   * A {@link ChannelBufferFactory} which merely allocates a heap buffer with
    23   * the specified capacity.  {@link HeapChannelBufferFactory} should perform
    24   * very well in most situations because it relies on the JVM garbage collector,
    25   * which is highly optimized for heap allocation.
    26   */
    27  public class HeapChannelBufferFactory extends AbstractChannelBufferFactory {
    28
    29      private static final HeapChannelBufferFactory INSTANCE_BE =
    30          new HeapChannelBufferFactory(ByteOrder.BIG_ENDIAN);
    31
    32      private static final HeapChannelBufferFactory INSTANCE_LE =
    33          new HeapChannelBufferFactory(ByteOrder.LITTLE_ENDIAN);
    34
    35      public static ChannelBufferFactory getInstance() {
    36          return INSTANCE_BE;
    37      }
    38
    39      public static ChannelBufferFactory getInstance(ByteOrder endianness) {
    40          if (endianness == ByteOrder.BIG_ENDIAN) {
    41              return INSTANCE_BE;
    42          } else if (endianness == ByteOrder.LITTLE_ENDIAN) {
    43              return INSTANCE_LE;
    44          } else if (endianness == null) {
    45              throw new NullPointerException("endianness");
    46          } else {
    47              throw new IllegalStateException("Should not reach here");
    48          }
    49      }
    50
    51      /**
    52       * Creates a new factory whose default {@link ByteOrder} is
    53       * {@link ByteOrder#BIG_ENDIAN}.
    54       */
    55      public HeapChannelBufferFactory() {
    56          super();
    57      }
    58
    59      /**
    60       * Creates a new factory with the specified default {@link ByteOrder}.
    61       *
    62       * @param defaultOrder the default {@link ByteOrder} of this factory
    63       */
    64      public HeapChannelBufferFactory(ByteOrder defaultOrder) {
    65          super(defaultOrder);
    66      }
    67
    68      public ChannelBuffer getBuffer(ByteOrder order, int capacity) {
    69          return ChannelBuffers.buffer(order, capacity);
    70      }
    71
    72      public ChannelBuffer getBuffer(ByteOrder order, byte[] array, int offset, int length) {
    73          return ChannelBuffers.wrappedBuffer(order, array, offset, length);
    74      }
    75
    76      public ChannelBuffer getBuffer(ByteBuffer nioBuffer) {
    77          if (nioBuffer.hasArray()) {
    78              return ChannelBuffers.wrappedBuffer(nioBuffer);
    79          }
    80
    81          ChannelBuffer buf = getBuffer(nioBuffer.order(), nioBuffer.remaining());
    82          int pos = nioBuffer.position();
    83          buf.writeBytes(nioBuffer);
    84          nioBuffer.position(pos);
    85          return buf;
    86      }
    87  }