org.netbeans.mdr.persistence.btreeimpl.btreestorage
Class CachedPageInputStream

java.lang.Object
  java.io.InputStream
      org.netbeans.mdr.persistence.btreeimpl.btreestorage.CachedPageInputStream

All Implemented Interfaces:

java.io.Closeable

public class CachedPageInputStream
extends java.io.InputStream

A stream composed of segments stored in CachedPages. The pages are pinned while members of a CachedPageInputStream. When done with the stream, close it to unpin the pages.

Constructor Summary

CachedPageInputStream()

Method Summary

void	addPage(CachedPage pg, int offst, int len) Add a page to the stream
int	available() report how many bytes are still unread
void	close() close the stream.
protected void	finalize() if the stream was never closed, unpin the pages now
void	mark(int readlimit) mark a spot in the stream, which reset will return to
boolean	markSupported() this class supports mark (since it's easy)
int	read() read a byte from the stream
int	read(byte[] b) read bytes into an array
int	read(byte[] b, int offset, int length) read bytes into an array
void	reset() return to where mark was last called, or to the beginning if mark was never called.

Methods inherited from class java.io.InputStream

skip

Methods inherited from class java.lang.Object

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

Constructor Detail

CachedPageInputStream

public CachedPageInputStream()

Method Detail

addPage

public void addPage(CachedPage pg,
                    int offst,
                    int len)

Add a page to the stream

Parameters:

pg - the page to add

offst - the offset in the page where the stream data begins

close

public void close()
           throws java.io.IOException

close the stream. This unpins all of the pages from the cache.

Specified by:

close in interface java.io.Closeable

Overrides:

close in class java.io.InputStream

Throws:

java.io.IOException - if there is an error unpinning the pages.

read

public int read()

read a byte from the stream

Specified by:

read in class java.io.InputStream

Returns:

The next byte in the stream, or -1 if at EOF.

read

public int read(byte[] b)

read bytes into an array

Overrides:

read in class java.io.InputStream

Parameters:

b - up to b.length bytes are read into this array

Returns:

The number of bytes read. If at EOF, -1 is returned

read

public int read(byte[] b,
                int offset,
                int length)

read bytes into an array

Overrides:

read in class java.io.InputStream

Parameters:

b - up to length bytes are read into this array

offset - the offset into the array at whch to start storing bytes

maximum - number of bytes to read

Returns:

The number of bytes read. If at EOF, -1 is returned

markSupported

public boolean markSupported()

this class supports mark (since it's easy)

Overrides:

markSupported in class java.io.InputStream

Returns:

true, since we support mark

mark

public void mark(int readlimit)

mark a spot in the stream, which reset will return to

Overrides:

mark in class java.io.InputStream

Parameters:

readlimit - ignored

available

public int available()

report how many bytes are still unread

Overrides:

available in class java.io.InputStream

Returns:

number of bytes left in stream

reset

public void reset()

return to where mark was last called, or to the beginning if mark was never called.

Overrides:

reset in class java.io.InputStream

finalize

protected void finalize()
                 throws StorageException

if the stream was never closed, unpin the pages now

Overrides:

finalize in class java.lang.Object

Throws:

StorageException