Class ByteArrayOutputStream

  • All Implemented Interfaces:
    Closeable, Flushable, AutoCloseable

    public class ByteArrayOutputStream
    extends OutputStream
    This class implements an output stream in which the data is written into a byte array. The buffer automatically grows as data is written to it.

    The data can be retrieved using toByteArray() and toString().

    Closing a ByteArrayOutputStream has no effect. The methods in this class can be called after the stream has been closed without generating an IOException.

    This is an alternative implementation of the ByteArrayOutputStream class. The original implementation only allocates 32 bytes at the beginning. As this class is designed for heavy duty it starts at 1024 bytes. In contrast to the original it doesn't reallocate the whole memory block but allocates additional buffers. This way no buffers need to be garbage collected and the contents don't have to be copied to the new buffer. This class is designed to behave exactly like the original. The only exception is the deprecated toString(int) method that has been ignored.

    • Constructor Detail

      • ByteArrayOutputStream

        public ByteArrayOutputStream()
        Creates a new byte array output stream. The buffer capacity is initially 1024 bytes, though its size increases if necessary.
      • ByteArrayOutputStream

        public ByteArrayOutputStream​(int size)
        Creates a new byte array output stream, with a buffer capacity of the specified size, in bytes.
        Parameters:
        size - the initial size
        Throws:
        IllegalArgumentException - if size is negative
    • Method Detail

      • write

        public void write​(byte[] b,
                          int off,
                          int len)
        Write the bytes to byte array.
        Overrides:
        write in class OutputStream
        Parameters:
        b - the bytes to write
        off - The start offset
        len - The number of bytes to write
      • write

        public void write​(int b)
        Write a byte to byte array.
        Specified by:
        write in class OutputStream
        Parameters:
        b - the byte to write
      • write

        public int write​(InputStream in)
                  throws IOException
        Writes the entire contents of the specified input stream to this byte stream. Bytes from the input stream are read directly into the internal buffers of this streams.
        Parameters:
        in - the input stream to read from
        Returns:
        total number of bytes read from the input stream (and written to this stream)
        Throws:
        IOException - if an I/O error occurs while reading the input stream
        Since:
        1.4
      • size

        public int size()
        Return the current size of the byte array.
        Returns:
        the current size of the byte array
      • close

        public void close()
                   throws IOException
        Closing a ByteArrayOutputStream has no effect. The methods in this class can be called after the stream has been closed without generating an IOException.
        Specified by:
        close in interface AutoCloseable
        Specified by:
        close in interface Closeable
        Overrides:
        close in class OutputStream
        Throws:
        IOException - never (this method should not declare this exception but it has to now due to backwards compatibility)
      • toBufferedInputStream

        public static InputStream toBufferedInputStream​(InputStream input)
                                                 throws IOException
        Fetches entire contents of an InputStream and represent same data as result InputStream.

        This method is useful where,

        • Source InputStream is slow.
        • It has network resources associated, so we cannot keep it open for long time.
        • It has network timeout associated.
        It can be used in favor of toByteArray(), since it avoids unnecessary allocation and copy of byte[].
        This method buffers the input internally, so there is no need to use a BufferedInputStream.
        Parameters:
        input - Stream to be fully buffered.
        Returns:
        A fully buffered stream.
        Throws:
        IOException - if an I/O error occurs
        Since:
        2.0
      • toBufferedInputStream

        public static InputStream toBufferedInputStream​(InputStream input,
                                                        int size)
                                                 throws IOException
        Fetches entire contents of an InputStream and represent same data as result InputStream.

        This method is useful where,

        • Source InputStream is slow.
        • It has network resources associated, so we cannot keep it open for long time.
        • It has network timeout associated.
        It can be used in favor of toByteArray(), since it avoids unnecessary allocation and copy of byte[].
        This method buffers the input internally, so there is no need to use a BufferedInputStream.
        Parameters:
        input - Stream to be fully buffered.
        size - the initial buffer size
        Returns:
        A fully buffered stream.
        Throws:
        IOException - if an I/O error occurs
        Since:
        2.5
      • toInputStream

        public InputStream toInputStream()
        Gets the current contents of this byte stream as a Input Stream. The returned stream is backed by buffers of this stream, avoiding memory allocation and copy, thus saving space and time.
        Returns:
        the current contents of this output stream.
        Since:
        2.5
        See Also:
        ByteArrayOutputStream.toByteArray(), reset()
      • toByteArray

        public byte[] toByteArray()
        Gets the curent contents of this byte stream as a byte array. The result is independent of this stream.
        Returns:
        the current contents of this output stream, as a byte array
        See Also:
        ByteArrayOutputStream.toByteArray()
      • toString

        public String toString​(Charset charset)
        Gets the curent contents of this byte stream as a string using the specified encoding.
        Parameters:
        charset - the character encoding
        Returns:
        the string converted from the byte array
        Since:
        2.5
        See Also:
        ByteArrayOutputStream.toString(String)