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# Class java.io.InputStream

    java.lang.Object
       |
       +----java.io.InputStream

public class InputStream
extends Object

An abstract class representing an input stream of bytes. All InputStreams are based on this class.

See Also:
  OutputStream, FilterInputStream, BufferedInputStream, DataInputStream, ByteArrayInputStream, PushbackInputStream

##

InputStream()

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available()
  Returns the number of bytes that can be read without blocking.
close()
  Closes the input stream.
mark(int)
  Marks the current position in the input stream.
markSupported()
  Returns a boolean indicating whether or not this stream type supports mark/reset.
read()
  Reads a byte of data.
read(byte[])
  Reads into an array of bytes.
read(byte[], int, int)
  Reads into an array of bytes.
reset()
  Repositions the stream to the last marked position.
skip(long)
  Skips n bytes of input.

##

InputStream

      public InputStream()

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read

      public abstract int read() throws IOException

  Reads a byte of data. This method will block if no input is available.

  Returns:
    the byte read, or -1 if the end of the stream is reached.
  Throws: IOException
    If an I/O error has occurred.

read

      public int read(byte b[]) throws IOException

  Reads into an array of bytes. This method will block until some input is available.

  Parameters:
    b - the buffer into which the data is read
  Returns:
    the actual number of bytes read, -1 is returned when the end of the stream is reached.
  Throws: IOException
    If an I/O error has occurred.

read

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

  Reads into an array of bytes. This method will block until some input is available.

  Parameters:
    b - the buffer into which the data is read
    off - the start offset of the data
    len - the maximum number of bytes read
  Returns:
    the actual number of bytes read, -1 is returned when the end of the stream is reached.
  Throws: IOException
    If an I/O error has occurred.

skip

      public long skip(long n) throws IOException

  Skips n bytes of input.

  Parameters:
    n - the number of bytes to be skipped
  Returns:
    the actual number of bytes skipped.
  Throws: IOException
    If an I/O error has occurred.

available

      public abstract int available() throws IOException

  Returns the number of bytes that can be read without blocking.

  Returns:
    the number of available bytes.

close

      public void close() throws IOException

  Closes the input stream. Must be called to release any resources associated with the stream.

  Throws: IOException
    If an I/O error has occurred.

mark

      public synchronized void mark(int readlimit)

  Marks the current position in the input stream. A subsequent call to reset() will reposition the stream at the last marked position so that subsequent reads will re-read the same bytes. The stream promises to allow readlimit bytes to be read before the mark position gets invalidated.

  Parameters:
    readlimit - the maximum limit of bytes allowed to be read before the mark position becomes invalid.

reset

      public synchronized void reset() throws IOException

  Repositions the stream to the last marked position. If the stream has not been marked, or if the mark has been invalidated, an IOException is thrown. Stream marks are intended to be used in situations where you need to read ahead a little to see what's in the stream. Often this is most easily done by invoking some general parser. If the stream is of the type handled by the parser, it just chugs along happily. If the stream is not of that type, the parser should toss an exception when it fails, which, if it happens within readlimit bytes, allows the outer code to reset the stream and try another parser.

  Throws: IOException
    If the stream has not been marked or if the mark has been invalidated.

markSupported

      public boolean markSupported()

  Returns a boolean indicating whether or not this stream type supports mark/reset.

  Returns:
    true if this stream type supports mark/reset; false otherwise.

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