streamutils.java

来自「apache的log4j源码」· Java 代码 · 共 125 行

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.log4j.lf5.util;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * Provides utility methods for input and output streams.
 *
 * @author Richard Wan
 */

// Contributed by ThoughtWorks Inc.

public abstract class StreamUtils {
  //--------------------------------------------------------------------------
  //   Constants:
  //--------------------------------------------------------------------------

  /**
   * Default value is 2048.
   */
  public static final int DEFAULT_BUFFER_SIZE = 2048;

  //--------------------------------------------------------------------------
  //   Protected Variables:
  //--------------------------------------------------------------------------

  //--------------------------------------------------------------------------
  //   Private Variables:
  //--------------------------------------------------------------------------

  //--------------------------------------------------------------------------
  //   Constructors:
  //--------------------------------------------------------------------------

  //--------------------------------------------------------------------------
  //   Public Methods:
  //--------------------------------------------------------------------------

  /**
   * Copies information from the input stream to the output stream using
   * a default buffer size of 2048 bytes.
   * @throws java.io.IOException
   */
  public static void copy(InputStream input, OutputStream output)
      throws IOException {
    copy(input, output, DEFAULT_BUFFER_SIZE);
  }

  /**
   * Copies information from the input stream to the output stream using
   * the specified buffer size
   * @throws java.io.IOException
   */
  public static void copy(InputStream input,
      OutputStream output,
      int bufferSize)
      throws IOException {
    byte[] buf = new byte[bufferSize];
    int bytesRead = input.read(buf);
    while (bytesRead != -1) {
      output.write(buf, 0, bytesRead);
      bytesRead = input.read(buf);
    }
    output.flush();
  }

  /**
   * Copies information between specified streams and then closes
   * both of the streams.
   * @throws java.io.IOException
   */
  public static void copyThenClose(InputStream input, OutputStream output)
      throws IOException {
    copy(input, output);
    input.close();
    output.close();
  }

  /**
   * @return a byte[] containing the information contained in the
   * specified InputStream.
   * @throws java.io.IOException
   */
  public static byte[] getBytes(InputStream input)
      throws IOException {
    ByteArrayOutputStream result = new ByteArrayOutputStream();
    copy(input, result);
    result.close();
    return result.toByteArray();
  }

  //--------------------------------------------------------------------------
  //   Protected Methods:
  //--------------------------------------------------------------------------

  //--------------------------------------------------------------------------
  //   Private Methods:
  //--------------------------------------------------------------------------

  //--------------------------------------------------------------------------
  //   Nested Top-Level Classes or Interfaces
  //--------------------------------------------------------------------------

}