Package org.apache.commons.io.output

Class AbstractByteArrayOutputStream

java.lang.Object
java.io.OutputStream
org.apache.commons.io.output.AbstractByteArrayOutputStream
All Implemented Interfaces:
Closeable, Flushable, AutoCloseable
Direct Known Subclasses:
ByteArrayOutputStream, UnsynchronizedByteArrayOutputStream
public abstract class AbstractByteArrayOutputStream extends OutputStream
This is the base class for implementing 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 an AbstractByteArrayOutputStream has no effect. The methods in this class can be called after the stream has been closed without generating an IOException.

This is the base for 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 ByteArrayOutputStream.toString(int) method that has been ignored.

Since:
2.7

  • Field Details

    • DEFAULT_SIZE

      static final int DEFAULT_SIZE
      See Also:

    • buffers

      private final List<byte[]> buffers
      The list of buffers, which grows and never reduces.

    • currentBufferIndex

      private int currentBufferIndex
      The index of the current buffer.

    • filledBufferSum

      private int filledBufferSum
      The total count of bytes in all the filled buffers.

    • currentBuffer

      private byte[] currentBuffer
      The current buffer.

    • count

      protected int count
      The total count of bytes written.

    • reuseBuffers

      private boolean reuseBuffers
      Flag to indicate if the buffers can be reused after reset

  • Constructor Details

    • AbstractByteArrayOutputStream

      public AbstractByteArrayOutputStream()

  • Method Details

    • close

      public void close() throws IOException
      Does nothing. 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)

    • needNewBuffer

      protected void needNewBuffer(int newCount)
      Makes a new buffer available either by allocating a new one or re-cycling an existing one.
      Parameters:
      newCount - the size of the buffer if one is created

    • reset

      public abstract void reset()
      See ByteArrayOutputStream.reset().
      See Also:

    • resetImpl

      protected void resetImpl()
      Implements a default reset behavior.
      See Also:

    • size

      public abstract int size()
      Returns the current size of the byte array.
      Returns:
      the current size of the byte array

    • toByteArray

      public abstract byte[] toByteArray()
      Gets the current 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:

    • toByteArrayImpl

      protected byte[] toByteArrayImpl()
      Gets the current 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:

    • toInputStream

      public abstract InputStream toInputStream()
      Gets the current contents of this byte stream as an 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:

    • toInputStream

      protected <T extends InputStream> InputStream toInputStream(AbstractByteArrayOutputStream.InputStreamConstructor<T> isConstructor)
      Gets the current contents of this byte stream as an Input Stream. The returned stream is backed by buffers of this stream, avoiding memory allocation and copy, thus saving space and time.
      Type Parameters:
      T - the type of the InputStream which makes up the SequenceInputStream.
      Parameters:
      isConstructor - A constructor for an InputStream which makes up the SequenceInputStream.
      Returns:
      the current contents of this output stream.
      Since:
      2.7
      See Also:

    • toString

      @Deprecated public String toString()
      Deprecated.
      Use toString(String) instead
      Gets the current contents of this byte stream as a string using the platform default charset.
      Overrides:
      toString in class Object
      Returns:
      the contents of the byte array as a String
      See Also:

    • toString

      public String toString(Charset charset)
      Gets the current 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:

    • toString

      public String toString(String enc) throws UnsupportedEncodingException
      Gets the current contents of this byte stream as a string using the specified encoding.
      Parameters:
      enc - the name of the character encoding
      Returns:
      the string converted from the byte array
      Throws:
      UnsupportedEncodingException - if the encoding is not supported
      See Also:

    • write

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

    • write

      public abstract 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 buffer of this stream.
      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

    • write

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

    • writeImpl

      protected void writeImpl(byte[] b, int off, int len)
      Writes the bytes to the byte array.
      Parameters:
      b - the bytes to write
      off - The start offset
      len - The number of bytes to write

    • writeImpl

      protected int writeImpl(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 buffer of this stream.
      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:
      2.7

    • writeImpl

      protected void writeImpl(int b)
      Write a byte to byte array.
      Parameters:
      b - the byte to write

    • writeTo

      public abstract void writeTo(OutputStream out) throws IOException
      Writes the entire contents of this byte stream to the specified output stream.
      Parameters:
      out - the output stream to write to
      Throws:
      IOException - if an I/O error occurs, such as if the stream is closed
      See Also:

    • writeToImpl

      protected void writeToImpl(OutputStream out) throws IOException
      Writes the entire contents of this byte stream to the specified output stream.
      Parameters:
      out - the output stream to write to
      Throws:
      IOException - if an I/O error occurs, such as if the stream is closed
      See Also: