Package org.springframework.util

Class FastByteArrayOutputStream

java.lang.Object
java.io.OutputStream
org.springframework.util.FastByteArrayOutputStream
All Implemented Interfaces:
Closeable, Flushable, AutoCloseable
public class FastByteArrayOutputStream extends OutputStream
A speedy alternative to ByteArrayOutputStream. Note that this variant does not extend ByteArrayOutputStream, unlike its sibling ResizableByteArrayOutputStream.

Unlike ByteArrayOutputStream, this implementation is backed by a ArrayDeque of byte[] buffers instead of one constantly resizing byte[]. It does not copy buffers when it gets expanded.

The initial buffer is only created when the stream is first written. There is also no copying of the internal buffers if the stream's content is extracted via the writeTo(OutputStream) method.

Since:
4.2
Author:
Craig Andrews, Juergen Hoeller
See Also:

  • Constructor Details

    • FastByteArrayOutputStream

      public FastByteArrayOutputStream()
      Create a new FastByteArrayOutputStream with the default initial capacity of 256 bytes.

    • FastByteArrayOutputStream

      public FastByteArrayOutputStream(int initialBlockSize)
      Create a new FastByteArrayOutputStream with the specified initial capacity.
      Parameters:
      initialBlockSize - the initial buffer size in bytes

  • Method Details

    • write

      public void write(int datum) throws IOException
      Specified by:
      write in class OutputStream
      Throws:
      IOException

    • write

      public void write(byte[] data, int offset, int length) throws IOException
      Overrides:
      write in class OutputStream
      Throws:
      IOException

    • close

      public void close()
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Overrides:
      close in class OutputStream

    • toString

      public String toString()
      Convert this stream's contents to a string by decoding the bytes using the platform's default character set. The length of the new String is a function of the character set, and hence may not be equal to the size of the buffers.

      This method always replaces malformed-input and unmappable-character sequences with the default replacement string for the platform's default character set. The CharsetDecoder class should be used when more control over the decoding process is required.

      Overrides:
      toString in class Object
      Returns:
      a String decoded from this stream's contents
      See Also:

    • toString

      public String toString(Charset charset)
      Convert this stream's contents to a string by decoding the bytes using the specified Charset.
      Parameters:
      charset - the Charset to use to decode the bytes
      Returns:
      a String decoded from this stream's contents
      Since:
      6.1.2
      See Also:

    • size

      public int size()
      Return the number of bytes stored in this FastByteArrayOutputStream.

    • toByteArrayUnsafe

      public byte[] toByteArrayUnsafe()
      Convert this stream's contents to a byte array and return the byte array.

      Also replaces the internal structures with the byte array to conserve memory: if the byte array is being created anyway, we might as well as use it. This approach also means that if this method is called twice without any writes in the interim, the second call is a no-op.

      This method is "unsafe" as it returns the internal buffer. Callers should not modify the returned buffer.

      Returns:
      the current contents of this stream as a byte array
      See Also:

    • toByteArray

      public byte[] toByteArray()
      Create a newly allocated byte array.

      Its size is the current size of this output stream, and it will contain the valid contents of the internal buffers.

      Returns:
      the current contents of this stream as a byte array
      See Also:

    • reset

      public void reset()
      Reset the contents of this FastByteArrayOutputStream.

      All currently accumulated output in the output stream is discarded. The output stream can be used again.

    • getInputStream

      public InputStream getInputStream()
      Get an InputStream to retrieve the contents of this FastByteArrayOutputStream.

      Note that if any methods are called on this FastByteArrayOutputStream (including, but not limited to, any of the write methods, reset(), toByteArray(), and toByteArrayUnsafe()) then the InputStream's behavior is undefined.

      Returns:
      InputStream of the contents of this FastByteArrayOutputStream

    • writeTo

      public void writeTo(OutputStream out) throws IOException
      Write the contents of this FastByteArrayOutputStream to the given OutputStream.
      Parameters:
      out - the OutputStream to write to
      Throws:
      IOException

    • resize

      public void resize(int targetCapacity)
      Resize the internal buffer size to the specified capacity.
      Parameters:
      targetCapacity - the desired size of the buffer
      Throws:
      IllegalArgumentException - if the given capacity is smaller than the actual size of the content stored in the buffer already
      See Also: