Class LazyByteArrayOutputStream

All Implemented Interfaces:
Closeable, Flushable, AutoCloseable

@NotThreadSafe public final class LazyByteArrayOutputStream extends OutputStream
ByteArrayOutputStream alternative exposing the internal buffer. Using this, callers don't need to call toByteArray() which copies the internal buffer.

This class doubles the size until the internal buffer reaches a configurable max size (default is 4MB), after which it begins growing the buffer in 25% increments. This is intended to help prevent an OutOfMemoryError during a resize of a large buffer.

A version of this class was originally created by Bela Ban as part of the JGroups library.

This class is not threadsafe as it will not support concurrent readers and writers.

Brian Stansberry, Dan Berindei
  • Field Details


      public static final int DEFAULT_SIZE
      See Also:

      public static final int DEFAULT_DOUBLING_SIZE
      Default buffer size after which if more buffer capacity is needed the buffer will grow by 25% rather than 100%
      See Also:
  • Constructor Details

    • LazyByteArrayOutputStream

      public LazyByteArrayOutputStream()
    • LazyByteArrayOutputStream

      public LazyByteArrayOutputStream(int size)
    • LazyByteArrayOutputStream

      public LazyByteArrayOutputStream(int size, int maxDoublingSize)
      Creates a new byte array output stream, with a buffer capacity of the specified size, in bytes.
      size - the initial size.
      maxDoublingSize - the buffer size, after which if more capacity is needed the buffer will grow by 25% rather than 100%
      IllegalArgumentException - if size is negative.
  • Method Details

    • getRawBuffer

      public byte[] getRawBuffer()
      Gets the internal buffer array. Note that the length of this array will almost certainly be longer than the data written to it; call size() to get the number of bytes of actual data.
    • getTrimmedBuffer

      public byte[] getTrimmedBuffer()
      Gets a buffer that is trimmed so that there are no excess bytes. If the current count does not match the underlying buffer than a new one is created with the written bytes.
      a byte[] that contains all the bytes written to this stream
    • write

      public void write(byte[] b, int off, int len)
      write in class OutputStream
    • write

      public void write(int b)
      Specified by:
      write in class OutputStream
    • getMaxDoublingSize

      public final int getMaxDoublingSize()
      Gets the highest internal buffer size after which if more capacity is needed the buffer will grow in 25% increments rather than 100%.
    • getNewBufferSize

      public int getNewBufferSize(int curSize, int minNewSize)
      Gets the number of bytes to which the internal buffer should be resized.
      curSize - the current number of bytes
      minNewSize - the minimum number of bytes required
      the size to which the internal buffer should be resized
    • size

      public int size()
      Overriden only to avoid unneeded synchronization