org.acplt.oncrpc
Class XdrTcpDecodingStream

java.lang.Object
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  +--org.acplt.oncrpc.XdrDecodingStream
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        +--org.acplt.oncrpc.XdrTcpDecodingStream

public class XdrTcpDecodingStream
extends XdrDecodingStream

The XdrTcpDecodingStream class provides the necessary functionality to XdrDecodingStream to receive XDR records from the network using the stream-oriented TCP/IP.


Field Summary
private  byte[] buffer
          The buffer which will be filled from the datagram socket and then be used to supply the information when decoding data.
private  int bufferHighmark
          Index of the last four byte word in the buffer, which has been read in from the datagram socket.
private  int bufferIndex
          The read pointer is an index into the buffer.
private  int fragmentLength
          Remaining number of bytes in this fragment -- and still to read.
private  boolean lastFragment
          Flag indicating that we've read the last fragment and thus reached the end of the record.
private  java.net.Socket socket
          The streaming socket to be used when receiving this XDR stream's buffer contents.
(package private)  java.io.InputStream stream
          The input stream used to pull the bytes off the network.
 
Constructor Summary
XdrTcpDecodingStream(java.net.Socket streamingSocket, int bufferSize)
          Construct a new XdrTcpDecodingStream object and associate it with the given streamingSocket for TCP/IP-based communication.
 
Method Summary
 void beginDecoding()
          Initiates decoding of the next XDR record.
 void close()
          Closes this decoding XDR stream and releases any system resources associated with this stream.
 void endDecoding()
          End decoding of the current XDR record.
private  void fill()
          Fills the internal buffer with the next chunk of data.
 java.net.InetAddress getSenderAddress()
          Returns the Internet address of the sender of the current XDR data.
 int getSenderPort()
          Returns the port number of the sender of the current XDR data.
private  void readBuffer(java.io.InputStream stream, byte[] bytes, int bytesToRead)
          Read into buffer exactly the amound of bytes specified.
 int xdrDecodeInt()
          Decodes (aka "deserializes") a "XDR int" value received from a XDR stream.
 void xdrDecodeOpaque(byte[] opaque, int offset, int length)
          Decodes (aka "deserializes") a XDR opaque value, which is represented by a vector of byte values, and starts at offset with a length of length.
 byte[] xdrDecodeOpaque(int length)
          Decodes (aka "deserializes") an opaque value, which is nothing more than a series of octets (or 8 bits wide bytes).
 
Methods inherited from class org.acplt.oncrpc.XdrDecodingStream
xdrDecodeBoolean, xdrDecodeBooleanFixedVector, xdrDecodeBooleanVector, xdrDecodeByte, xdrDecodeByteFixedVector, xdrDecodeByteVector, xdrDecodeDouble, xdrDecodeDoubleFixedVector, xdrDecodeDoubleVector, xdrDecodeDynamicOpaque, xdrDecodeFloat, xdrDecodeFloatFixedVector, xdrDecodeFloatVector, xdrDecodeIntFixedVector, xdrDecodeIntVector, xdrDecodeLong, xdrDecodeLongFixedVector, xdrDecodeLongVector, xdrDecodeOpaque, xdrDecodeShort, xdrDecodeShortFixedVector, xdrDecodeShortVector, xdrDecodeString, xdrDecodeStringFixedVector, xdrDecodeStringVector
 
Methods inherited from class java.lang.Object
, clone, equals, finalize, getClass, hashCode, notify, notifyAll, registerNatives, toString, wait, wait, wait
 

Field Detail

socket

private java.net.Socket socket
The streaming socket to be used when receiving this XDR stream's buffer contents.

stream

java.io.InputStream stream
The input stream used to pull the bytes off the network.

buffer

private byte[] buffer
The buffer which will be filled from the datagram socket and then be used to supply the information when decoding data.

bufferIndex

private int bufferIndex
The read pointer is an index into the buffer.

bufferHighmark

private int bufferHighmark
Index of the last four byte word in the buffer, which has been read in from the datagram socket.

fragmentLength

private int fragmentLength
Remaining number of bytes in this fragment -- and still to read.

lastFragment

private boolean lastFragment
Flag indicating that we've read the last fragment and thus reached the end of the record.
Constructor Detail

XdrTcpDecodingStream

public XdrTcpDecodingStream(java.net.Socket streamingSocket,
                            int bufferSize)
                     throws java.io.IOException
Construct a new XdrTcpDecodingStream object and associate it with the given streamingSocket for TCP/IP-based communication.
Parameters:
streamingSocket - Socket from which XDR data is received.
bufferSize - Size of packet buffer for storing received XDR data.
Method Detail

getSenderAddress

public java.net.InetAddress getSenderAddress()
Returns the Internet address of the sender of the current XDR data. This method should only be called after beginDecoding(), otherwise it might return stale information.
Returns:
InetAddress of the sender of the current XDR data.
Overrides:
getSenderAddress in class XdrDecodingStream

getSenderPort

public int getSenderPort()
Returns the port number of the sender of the current XDR data. This method should only be called after beginDecoding(), otherwise it might return stale information.
Returns:
Port number of the sender of the current XDR data.
Overrides:
getSenderPort in class XdrDecodingStream

beginDecoding

public void beginDecoding()
                   throws OncRpcException,
                          java.io.IOException
Initiates decoding of the next XDR record. For TCP-based XDR decoding streams this reads in the next chunk of data from the network socket (a chunk of data is not necessary the same as a fragment, just enough to fill the internal buffer or receive the remaining part of a fragment).

Read in the next bunch of bytes. This can be either a complete fragment, or if the fragments sent by the communication partner are too large for our buffer, only parts of fragments. In every case, this method ensures that there will be more data available in the buffer (or else an exception thrown).

Throws:
OncRpcException - if an ONC/RPC error occurs.
java.io.IOException - if an I/O error occurs.
Overrides:
beginDecoding in class XdrDecodingStream

readBuffer

private void readBuffer(java.io.InputStream stream,
                        byte[] bytes,
                        int bytesToRead)
                 throws java.io.IOException,
                        OncRpcException
Read into buffer exactly the amound of bytes specified.
Parameters:
stream - Input stream to read byte data from.
bytes - buffer receiving data.
bytesToRead - number of bytes to read into buffer.
Throws:
OncRpcException - if EOF is reached before all bytes could be read.
java.io.IOException - if an I/O error occurs.

fill

private void fill()
           throws OncRpcException,
                  java.io.IOException
Fills the internal buffer with the next chunk of data. The chunk is either as long as the buffer or as long as the remaining part of the current XDR fragment, whichever is smaller.
Throws:
OncRpcException - if an ONC/RPC error occurs.
java.io.IOException - if an I/O error occurs.

endDecoding

public void endDecoding()
                 throws OncRpcException,
                        java.io.IOException
End decoding of the current XDR record. The general contract of endDecoding is that calling it is an indication that the current record is no more interesting to the caller and any allocated data for this record can be freed.

This method overrides XdrDecodingStream.endDecoding(). It reads in and throws away fragments until it reaches the last fragment.

Throws:
OncRpcException - if an ONC/RPC error occurs.
java.io.IOException - if an I/O error occurs.
Overrides:
endDecoding in class XdrDecodingStream

close

public void close()
           throws OncRpcException,
                  java.io.IOException
Closes this decoding XDR stream and releases any system resources associated with this stream. A closed XDR stream cannot perform decoding operations and cannot be reopened.

This implementation frees the allocated buffer but does not close the associated datagram socket. It only throws away the reference to this socket.

Throws:
OncRpcException - if an ONC/RPC error occurs.
java.io.IOException - if an I/O error occurs.
Overrides:
close in class XdrDecodingStream

xdrDecodeInt

public int xdrDecodeInt()
                 throws OncRpcException,
                        java.io.IOException
Decodes (aka "deserializes") a "XDR int" value received from a XDR stream. A XDR int is 32 bits wide -- the same width Java's "int" data type has.
Returns:
The decoded int value.
Throws:
OncRpcException - if an ONC/RPC error occurs.
java.io.IOException - if an I/O error occurs.
Overrides:
xdrDecodeInt in class XdrDecodingStream

xdrDecodeOpaque

public byte[] xdrDecodeOpaque(int length)
                       throws OncRpcException,
                              java.io.IOException
Decodes (aka "deserializes") an opaque value, which is nothing more than a series of octets (or 8 bits wide bytes). Because the length of the opaque value is given, we don't need to retrieve it from the XDR stream. This is different from xdrDecodeOpaque(byte[], int, int) where first the length of the opaque value is retrieved from the XDR stream.
Parameters:
length - Length of opaque data to decode.
Returns:
Opaque data as a byte vector.
Throws:
OncRpcException - if an ONC/RPC error occurs.
java.io.IOException - if an I/O error occurs.
Overrides:
xdrDecodeOpaque in class XdrDecodingStream

xdrDecodeOpaque

public void xdrDecodeOpaque(byte[] opaque,
                            int offset,
                            int length)
                     throws OncRpcException,
                            java.io.IOException
Decodes (aka "deserializes") a XDR opaque value, which is represented by a vector of byte values, and starts at offset with a length of length. Only the opaque value is decoded, so the caller has to know how long the opaque value will be. The decoded data is always padded to be a multiple of four (because that's what the sender does).
Parameters:
opaque - Byte vector which will receive the decoded opaque value.
offset - Start offset in the byte vector.
length - the number of bytes to decode.
Returns:
The number of opaque bytes read.
Throws:
OncRpcException - if an ONC/RPC error occurs.
java.io.IOException - if an I/O error occurs.
Overrides:
xdrDecodeOpaque in class XdrDecodingStream