condor.cedar
Class CedarInputStream

Object
  InputStream
      FilterInputStream
          condor.cedar.CedarInputStream

All Implemented Interfaces:

DataInput

public class CedarInputStream

extends FilterInputStream

implements DataInput

A Java input stream that more-or-less corresponds to the C++ class ReliSock. Except for floats, this class attempts to be compatible with the existing Condor conventions for sending data over a connection. See The package description for details.

Version:

$Revision: 1.14 $

Author:

Marvin solomon

Field Summary

Fields inherited from class FilterInputStream

in

Constructor Summary

CedarInputStream(InputStream in)
Creates a new CedarInputStream wrapping an exising stream.

Method Summary

int	available() Returns the number of bytes buffered.
void	close() Closes the underlying stream and discards all buffered data.
int	getByteCount() Returns the number of "raw" bytes consumed from the original input stream, including Cedar overhead, since this stream was opened.
void	mark(int n) Does nothing (mark not supported).
boolean	markSupported() Always returns false (mark not supported).
boolean	nextMessage() Advances the input stream to the start of the next message.
int	read() Reads one byte from the input stream.
int	read(byte[] b) Reads at most b.length bytes from the input stream.
int	read(byte[] b, int off, int len) Reads at most len bytes from the input stream into buffer b, starting at offset off.
boolean	readBoolean() Reads one boolean from the input stream.
byte	readByte() Reads a byte from the input stream.
char	readChar() Reads one character from the input stream.
double	readDouble() Reads a double from the input stream.
float	readFloat() Reads a float from the input stream.
void	readFully(byte[] b) Equivalent to readFully(b, 0, b.length).
void	readFully(byte[] b, int off, int len) Reads a specified number of bytes, or throws an exception if there are not that many more bytes before the next end-of-message indication.
int	readInt() Reads an integer from the input stream.
String	readLine() Deprecated. Use readUTF() instead.
long	readLong() Reads a long (64-bit) integer from the input stream.
short	readShort() Reads a short from the input stream.
int	readUnsignedByte() Reads an unsigned byte from the input stream.
int	readUnsignedShort() Reads an unsigned short from the input stream.
String	readUTF() Reads a null-terminated string in modified UTF-8 encoding from the input and throw away the terminating null.
int	readUTFchar() Reads one character in UTF format from the input.
void	reset() Always throws IOException (mark not supported).
long	skip(long n) Skips up n bytes or to the end of the current message, whichever comes first.
int	skipBytes(int n) Equivalent to (int) skip(n).

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CedarInputStream

public CedarInputStream(InputStream in)

Creates a new CedarInputStream wrapping an exising stream.

Parameters:

in - the source of raw bytes.

Method Detail

nextMessage

public boolean nextMessage()
                    throws IOException

Advances the input stream to the start of the next message. If the stream is already in the last message, the buffer is left looking as if the stream is positioned inside a zero-length message. Note that this is the only method of this class that will read beyond the end of the current message.

Returns:

false if the stream is positioned inside the last message of input at the point of call.

Throws:

IOException - if there is an I/O error on the underlying stream.

read

public int read()
         throws IOException

Reads one byte from the input stream.

Returns:

the next input byte, or -1 if the stream is positioned at end-of-message.

Throws:

IOException - if there is an I/O error on the underlying stream.

read

public int read(byte[] b)
         throws IOException

Reads at most b.length bytes from the input stream.

Parameters:

b - the place to put the data.

Returns:

the number of bytes read. Returns -1 if the stream is at end-of-message. Never returns 0.

Throws:

IOException - if there is an I/O error on the underlying stream.

read

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

Reads at most len bytes from the input stream into buffer b, starting at offset off.

Parameters:

b - the place to put the data.

off - starting offset in b.

len - maximum number of bytes to read.

Returns:

the number of bytes read. Returns -1 if the stream is at end-of-message. Never returns 0.

Throws:

IOException - if there is an I/O error on the underlying stream.

skip

public long skip(long n)
          throws IOException

Skips up n bytes or to the end of the current message, whichever comes first.

Parameters:

n - the maximum number of bytes to skip.

Returns:

the number of bytes skipped.

Throws:

IOException - if there is an I/O error on the underlying stream.

available

public int available()
              throws IOException

Returns the number of bytes buffered. If no data is currently buffered, first read until there is some data buffered, or end-of-message is encountered, whichever comes first.

Returns:

the number of bytes buffered, perhaps after first refilling the buffer.

Throws:

IOException - if there is an I/O error on the underlying stream.

close

public void close()
           throws IOException

Closes the underlying stream and discards all buffered data.

Throws:

IOException - if there is an I/O error on the underlying stream.

mark

public void mark(int n)

Does nothing (mark not supported).

reset

public void reset()
           throws IOException

Always throws IOException (mark not supported).

Throws:

IOException - always.

markSupported

public boolean markSupported()

Always returns false (mark not supported).

readFully

public void readFully(byte[] b)
               throws IOException

Equivalent to readFully(b, 0, b.length).

Specified by:

readFully in interface DataInput

Parameters:

b - a place to put the data.

Throws:

IOException - if there is an I/O error on the underlying stream.

readFully

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

Reads a specified number of bytes, or throws an exception if there are not that many more bytes before the next end-of-message indication.

Specified by:

readFully in interface DataInput

Parameters:

b - place to put the data.

off - offset within b where the data starts.

len - number of bytes to read.

Throws:

EOFException - if end-of-message is encountered before the specified number of bytes are read.

IOException - if there is an I/O error on the underlying stream.

skipBytes

public int skipBytes(int n)
              throws IOException

Equivalent to (int) skip(n).

Specified by:

skipBytes in interface DataInput

Parameters:

n - the maximum number of bytes to skip.

Returns:

the number of bytes skipped.

Throws:

IOException - if there is an I/O error on the underlying stream.

readBoolean

public boolean readBoolean()
                    throws IOException

Reads one boolean from the input stream.

Specified by:

readBoolean in interface DataInput

Returns:

the value read.

Throws:

IOException - if there is an I/O error on the underlying stream.

readByte

public byte readByte()
              throws IOException

Reads a byte from the input stream.

Specified by:

readByte in interface DataInput

Returns:

the value read.

Throws:

IOException - if there is an I/O error on the underlying stream.

readUnsignedByte

public int readUnsignedByte()
                     throws IOException

Reads an unsigned byte from the input stream.

Specified by:

readUnsignedByte in interface DataInput

Returns:

the value read.

Throws:

IOException - if there is an I/O error on the underlying stream.

readShort

public short readShort()
                throws IOException

Reads a short from the input stream.

Specified by:

readShort in interface DataInput

Returns:

the value read.

Throws:

IOException - if there is an I/O error on the underlying stream.

readUnsignedShort

public int readUnsignedShort()
                      throws IOException

Reads an unsigned short from the input stream.

Specified by:

readUnsignedShort in interface DataInput

Returns:

the value read.

Throws:

IOException - if there is an I/O error on the underlying stream.

readChar

public char readChar()
              throws IOException

Reads one character from the input stream.

Specified by:

readChar in interface DataInput

Returns:

the value read.

Throws:

IOException - if there is an I/O error on the underlying stream.

readInt

public int readInt()
            throws IOException

Reads an integer from the input stream.

Specified by:

readInt in interface DataInput

Returns:

the value read.

Throws:

IOException - if there is an I/O error on the underlying stream.

readLong

public long readLong()
              throws IOException

Reads a long (64-bit) integer from the input stream.

Specified by:

readLong in interface DataInput

Returns:

the value read.

Throws:

IOException - if there is an I/O error on the underlying stream.

readFloat

public float readFloat()
                throws IOException

Reads a float from the input stream.

Specified by:

readFloat in interface DataInput

Returns:

the value read.

Throws:

IOException - if there is an I/O error on the underlying stream.

readDouble

public double readDouble()
                  throws IOException

Reads a double from the input stream.

Specified by:

readDouble in interface DataInput

Returns:

the value read.

Throws:

IOException - if there is an I/O error on the underlying stream.

readLine

public String readLine()
                throws IOException

Deprecated. Use readUTF() instead.

Reads bytes, converting them to characters, until end-of-line or end-of-message is seen. See DataInput.readLine() for details. It is not clear to me why this ridiculous thing is not deprecated.

Specified by:

readLine in interface DataInput

Returns:

a string composed of the characters read.

Throws:

IOException - if there is an I/O error on the underlying stream.

readUTF

public String readUTF()
               throws IOException

Reads a null-terminated string in modified UTF-8 encoding from the input and throw away the terminating null.

Specified by:

readUTF in interface DataInput

Returns:

the value read.

Throws:

UTFDataFormatException - if the input data contains a bad escape sequece.

EOFException - if end-of-message is encountered before a null.

IOException - if there is an I/O error on the underlying stream.

readUTFchar

public final int readUTFchar()
                      throws IOException

Reads one character in UTF format from the input.

Returns:

the character read, or -1 if a null is encountered in the input stream (note that a null in the input stream cannot be part of the UTF encoding of any character).

Throws:

UTFDataFormatException - if the input data contains a bad escape sequece.

EOFException - if end-of-message is encountered.

IOException - if there is an I/O error on the underlying stream.

getByteCount

public int getByteCount()

Returns the number of "raw" bytes consumed from the original input stream, including Cedar overhead, since this stream was opened.

Returns:

the number of bytes read.