com.equilibrium.utilities

Class PartialInputStream

java.lang.Object

java.io.InputStream

com.equilibrium.utilities.PartialInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

public class PartialInputStream
extends InputStream

Since:

10/8/13

Author:

James Hays

Constructor Summary

Constructors

Constructor and Description
PartialInputStream(InputStream stream, int start, int length)

Method Summary

Methods

Modifier and Type	Method and Description
int	available() Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller of a method for this input stream.
void	close() Closes this input stream and releases any system resources associated with the stream.
void	mark(int readLimit) Marks the current position in this input stream.
boolean	markSupported() Tests if this input stream supports the mark and reset methods.
int	read() Reads the next byte of data from this input stream.
int	read(byte[] b) Reads up to byte.length bytes of data from this input stream into an array of bytes.
int	read(byte[] b, int off, int len) Reads up to len bytes of data from this input stream into an array of bytes.
void	reset() mark method was last called on this input stream.
long	skip(long skip) Skips over and discards n bytes of data from the input stream.

Methods inherited from class java.lang.Object

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

Constructor Detail

PartialInputStream

public PartialInputStream(InputStream stream,
                  int start,
                  int length)
                   throws IOException

Throws:

IOException

Method Detail

read

public int read()
         throws IOException

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 method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

This method simply performs _stream.read() and returns the result.

Specified by:

read in class InputStream

Returns:

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

Throws:

IOException - if an I/O error occurs.

See Also:

FilterInputStream.in

read

public int read(byte[] b)
         throws IOException

Reads up to byte.length bytes of data from this input stream into an array of bytes. This method blocks until some input is available.

This method simply performs the call read(b, 0, b.length) and returns the result. It is important that it does not do _stream.read(b) instead; certain subclasses of FilterInputStream depend on the implementation strategy actually used.

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, or -1 if there is no more data because the end of the stream has been reached.

Throws:

IOException - if an I/O error occurs.

See Also:

FilterInputStream.read(byte[], int, int)

read

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

Reads up to len bytes of data from this input stream into an array of bytes. If len is not zero, the method blocks until some input is available; otherwise, no bytes are read and 0 is returned.

This method simply performs _stream.read(b, off, len) and returns the result.

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

IOException - if an I/O error occurs.

See Also:

FilterInputStream.in

skip

public long skip(long skip)
          throws IOException

Skips over and discards n bytes of data from the input stream. The skip method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly 0. The actual number of bytes skipped is returned.

This method simply performs _stream.skip(n).

Overrides:

skip in class InputStream

Parameters:

skip - the number of bytes to be skipped.

Returns:

the actual number of bytes skipped.

Throws:

IOException - if the stream does not support seek, or if some other I/O error occurs.

available

public int available()
              throws IOException

Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller of a method for this input stream. The next caller might be the same thread or another thread. A single read or skip of this many bytes will not block, but may read or skip fewer bytes.

This method returns the result of in.available().

Overrides:

available in class InputStream

Returns:

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

Throws:

IOException - if an I/O error occurs.

close

public void close()
           throws IOException

Closes this input stream and releases any system resources associated with the stream. This method simply performs _stream.close().

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.

See Also:

FilterInputStream.in

mark

public void mark(int readLimit)

Marks the current position in this input stream. A subsequent call to the reset method repositions this stream at the last marked position so that subsequent reads re-read the same bytes.

The readlimit argument tells this input stream to allow that many bytes to be read before the mark position gets invalidated.

This method simply performs _stream.mark(readlimit).

Overrides:

mark in class InputStream

Parameters:

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

See Also:

FilterInputStream.in, FilterInputStream.reset()

reset

public void reset()
           throws IOException

mark method was last called on this input stream.

This method simply performs _stream.reset().

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 parse, it just chugs along happily. If the stream is not of that type, the parser should toss an exception when it fails. If this happens within readlimit bytes, it allows the outer code to reset the stream and try another parser.

Overrides:

reset in class InputStream

Throws:

IOException - if the stream has not been marked or if the mark has been invalidated.

See Also:

FilterInputStream.in, FilterInputStream.mark(int)

markSupported

public boolean markSupported()

Tests if this input stream supports the mark and reset methods. This method simply performs _stream.markSupported().

Overrides:

markSupported in class InputStream

Returns:

true if this stream type supports the mark and reset method; false otherwise.

See Also:

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