com.embeddedunveiled.serial

Class SerialComInByteStream

java.lang.Object

java.io.InputStream

com.embeddedunveiled.serial.SerialComInByteStream

All Implemented Interfaces:

Closeable, AutoCloseable

public final class SerialComInByteStream
extends InputStream

Represents an input stream of bytes which is received from serial port.

Application design should make sure that the port is not closed if there exist a read method which is blocked (waiting for data byte) on the same port.

Advance applications may fine tune the timing behavior using fineTuneReadBehaviour() API defined in SerialComManager class.

Author:

Rishi Gupta

Constructor Summary

Constructors

Constructor and Description
SerialComInByteStream(SerialComManager scm, SerialComPortHandleInfo portHandleInfo, long handle, SerialComManager.SMODE streamMode) Construct and allocates a new SerialComInByteStream object with given details.

Method Summary

Methods

Modifier and Type	Method and Description
int	available() Returns an estimate of the minimum number of bytes that can be read from this input stream without blocking by the next invocation of a method for this input stream.
void	close() This method releases the InputStream object associated with the operating handle.
void	mark(int a) SCM does not support mark and reset of input stream.
boolean	markSupported() SCM does not support mark and reset of input stream.
int	read() Reads the next byte of data from the input stream.
int	read(byte[] b) Reads some number of bytes from the input stream and stores them into the buffer array b.
int	read(byte[] b, int off, int len) Reads up to len bytes of data from the input stream into an array of bytes.
void	reset() SCM does not support reset.
long	skip(long number) SCM does not support skip.

Methods inherited from class java.lang.Object

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

Constructor Detail

SerialComInByteStream

public SerialComInByteStream(SerialComManager scm,
                     SerialComPortHandleInfo portHandleInfo,
                     long handle,
                     SerialComManager.SMODE streamMode)
                      throws SerialComException

Construct and allocates a new SerialComInByteStream object with given details.

Parameters:

scm - instance of SerialComManager class with which this stream will associate itself.

handle - handle of the serial port on which to read data bytes.

streamMode - indicates blocking or non-blocking behavior of stream.

Throws:

SerialComException - if the input stream can not be prepared for the specified read behavior.

Method Detail

available

public int available()
              throws IOException

Returns an estimate of the minimum number of bytes that can be read from this input stream without blocking by the next invocation of a method for this input stream.

Overrides:

available in class InputStream

Returns:

an estimate of the minimum number of bytes available for reading.

Throws:

IOException - if an I/O error occurs or if stream has been closed already.

close

public void close()
           throws IOException

This method releases the InputStream object associated with the operating handle.

To actually close the port closeComPort() method should be used.

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 or if stream has been closed already.

mark

public void mark(int a)

SCM does not support mark and reset of input stream. If required, it can be developed at application level.

Overrides:

mark in class InputStream

markSupported

public boolean markSupported()

SCM does not support mark and reset of input stream. If required, it can be developed at application level.

Overrides:

markSupported in class InputStream

Returns:

always returns false.

read

public int read()
         throws IOException

Reads the next byte of data from the input stream. The value byte is returned as an int in the range 0 to 255.

For blocking mode this method returns the next byte of data. For non-blocking mode this method returns the next byte of data if it is available otherwise -1 if there is no data at serial port.

Specified by:

read in class InputStream

Returns:

the next byte of data or -1.

Throws:

IOException - if an I/O error occurs or if stream has been closed already.

read

public int read(byte[] b)
         throws IOException

Reads some number of bytes from the input stream and stores them into the buffer array b. The number of bytes actually read is returned as an integer. This method blocks until input data is available or an exception is thrown.

If the length of b is zero, then no bytes are read and 0 is returned; otherwise, there is an attempt to read at least one byte.

The first byte read is stored into element b[0], the next one into b[1], and so on. The number of bytes read is, at most, equal to the length of b. Let k be the number of bytes actually read; these bytes will be stored in elements b[0] through b[k-1], leaving elements b[k] through b[b.length-1] unaffected.

The read(b) method for class SerialComInByteStream has the same effect as : read(b, 0, b.length).

Overrides:

read in class InputStream

Parameters:

b - the buffer into which the data is read.

Returns:

the total number of bytes read into the buffer.

Throws:

IOException - if an I/O error occurs or if input stream has been closed.

NullPointerException - if b is null.

read

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

Reads up to len bytes of data from the input stream into an array of bytes. An attempt is made to read as many as len bytes, but a smaller number may be read. The number of bytes actually read is returned as an integer.

If len is zero, then no bytes are read and 0 is returned; otherwise, there is an attempt to read at least one byte and stored into b.

The first byte read is stored into element b[off], the next one into b[off+1], and so on. The number of bytes read is, at most, equal to len. Let k be the number of bytes actually read; these bytes will be stored in elements b[off] through b[off+k-1], leaving elements b[off+k] through b[off+len-1] unaffected.

In every case, elements b[0] through b[off] and elements b[off+len] through b[b.length-1] are unaffected.

For blocking mode, this method blocks until input data is available or an exception is thrown. For non-blocking mode it attempts to read data, returns data byte if read. It will return -1 if there is no data at serial port.

Overrides:

read in class InputStream

Parameters:

b - the buffer into which the data is read.

off - the start offset in array b at which the data is written.

len - the maximum number of bytes to read.

Returns:

the total number of bytes read into the buffer or 0 if len is zero or -1 if there is no data (non-blocking).

Throws:

IOException - if an I/O error occurs or if input stream has been closed.

NullPointerException - if b is null.

IllegalArgumentException - if data is not a byte type array.

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

reset

public void reset()
           throws IOException

SCM does not support reset. If required, it can be developed at application level.

Overrides:

reset in class InputStream

Throws:

IOException

skip

public long skip(long number)

SCM does not support skip. If required, it can be developed at application level.

Overrides:

skip in class InputStream

Parameters:

number - of bytes to skip.

Returns:

always returns 0.