Java compact1, compact2, compact3 java.io Class ByteArrayInputStream（JDK8）

Field Detail

• buf

  protected byte[] buf

  An array of bytes that was provided by the creator of the stream. Elements buf[0] through buf[count-1] are the only bytes that can ever be read from the stream; element buf[pos] is the next byte to be read.

• pos

  protected int pos

  The index of the next character to read from the input stream buffer. This value should always be nonnegative and not larger than the value of count. The next byte to be read from the input stream buffer will be buf[pos].

• mark

  protected int mark

  The currently marked position in the stream. ByteArrayInputStream objects are marked at position zero by default when constructed. They may be marked at another position within the buffer by the mark() method. The current buffer position is set to this point by the reset() method.

  If no mark has been set, then the value of mark is the offset passed to the constructor (or 0 if the offset was not supplied).

  Since:

  JDK1.1

• count

  protected int count

  The index one greater than the last valid character in the input stream buffer. This value should always be nonnegative and not larger than the length of buf. It is one greater than the position of the last byte within buf that can ever be read from the input stream buffer.

Constructor Detail

• ByteArrayInputStream

  public ByteArrayInputStream(byte[] buf)

  Creates a ByteArrayInputStream so that it uses buf as its buffer array. The buffer array is not copied. The initial value of pos is 0 and the initial value of count is the length of buf.

  Parameters:

  buf - the input buffer.

• ByteArrayInputStream

  public ByteArrayInputStream(byte[] buf,
                              int offset,
                              int length)

  Creates ByteArrayInputStream that uses buf as its buffer array. The initial value of pos is offset and the initial value of count is the minimum of offset+length and buf.length. The buffer array is not copied. The buffer's mark is set to the specified offset.

  Parameters:

  buf - the input buffer.

  offset - the offset in the buffer of the first byte to read.

  length - the maximum number of bytes to read from the buffer.

Method Detail

• read

  public int read()

  Reads the next byte of data from this input stream. The value byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned.

  This read method cannot block.

  Specified by:

  read in class InputStream

  Returns:

  the next byte of data, or -1 if the end of the stream has been reached.

• read

  public int read(byte[] b,
                  int off,
                  int len)

  Reads up to len bytes of data into an array of bytes from this input stream. If pos equals count, then -1 is returned to indicate end of file. Otherwise, the number k of bytes read is equal to the smaller of len and count-pos. If k is positive, then bytes buf[pos] through buf[pos+k-1] are copied into b[off] through b[off+k-1] in the manner performed by System.arraycopy. The value k is added into pos and k is returned.

  This read method cannot block.

  Overrides:

  read in class InputStream

  Parameters:

  b - the buffer into which the data is read.

  off - the start offset in the destination array b

  len - the maximum number of bytes read.

  Returns:

  the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.

  Throws:

  NullPointerException - If b is null.

  IndexOutOfBoundsException - If off is negative, len is negative, or len is greater than b.length - off

  See Also:

  InputStream.read()

• skip

  public long skip(long n)

  Skips n bytes of input from this input stream. Fewer bytes might be skipped if the end of the input stream is reached. The actual number k of bytes to be skipped is equal to the smaller of n and count-pos. The value k is added into pos and k is returned.

  Overrides:

  skip in class InputStream

  Parameters:

  n - the number of bytes to be skipped.

  Returns:

  the actual number of bytes skipped.

• available

  public int available()

  Returns the number of remaining bytes that can be read (or skipped over) from this input stream.

  The value returned is count - pos, which is the number of bytes remaining to be read from the input buffer.

  Overrides:

  available in class InputStream

  Returns:

  the number of remaining bytes that can be read (or skipped over) from this input stream without blocking.

• markSupported

  public boolean markSupported()

  Tests if this InputStream supports mark/reset. The markSupported method of ByteArrayInputStream always returns true.

  Overrides:

  markSupported in class InputStream

  Returns:

  true if this stream instance supports the mark and reset methods; false otherwise.

  Since:

  JDK1.1

  See Also:

  InputStream.mark(int), InputStream.reset()

• mark

  public void mark(int readAheadLimit)

  Set the current marked position in the stream. ByteArrayInputStream objects are marked at position zero by default when constructed. They may be marked at another position within the buffer by this method.

  If no mark has been set, then the value of the mark is the offset passed to the constructor (or 0 if the offset was not supplied).

  Note: The readAheadLimit for this class has no meaning.

  Overrides:

  mark in class InputStream

  Parameters:

  readAheadLimit - the maximum limit of bytes that can be read before the mark position becomes invalid.

  Since:

  JDK1.1

  See Also:

  InputStream.reset()

• reset

  public void reset()

  Resets the buffer to the marked position. The marked position is 0 unless another position was marked or an offset was specified in the constructor.

  Overrides:

  reset in class InputStream

  See Also:

  InputStream.mark(int), IOException

• close

  public void close()
             throws IOException

  Closing a ByteArrayInputStream 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 Closeable

  Specified by:

  close in interface AutoCloseable

  Overrides:

  close in class InputStream

  Throws:

  IOException - if an I/O error occurs.