com.quadcap.sql.file.Block Class Reference

Inheritance diagram for com.quadcap.sql.file.Block:

Detailed Description

This class represents a block/page of data in a random access file, which may be cached.

The key is an Integer specifying the block number, while the data is a byte array containing the actual data.

Author:: Stan Bailes

Definition at line 55 of file Block.java.

Public Member Functions

long getPageNum ()

Return this page's block number.

void init (Object store, long key) throws IOException

Initialize this block.

final void flush () throws IOException

Write the contents of the buffer back to the underlying store.

final Object getData ()

From the Cacheable class, return the underlying data object.

byte[] getDataAndReset ()

Return a reference to the array containing the data for this block, and create a new buffer, so that the reference returned can be used in a subsequent setData call to another buffer.

void setData (Object obj)

From the Cacheable class, set the underlying data object.

String toString ()

Only a debugging version implemented so far...

final int read (int pos, byte[] pbuf, int offset, int len)

Read a range of bytes from the page.

final int write (int pos, byte[] pbuf, int offset, int len)

Write a range of bytes to the page.

final byte readByte (int pos)

final void writeByte (int pos, byte val)

final short readShort (int pos)

Read a short (2-byte) value from the page.

final void writeShort (int pos, short val)

Write a short (2-byte) value to the page.

final int readInt (int pos)

Read an integer (4-byte) value from the page.

final void writeInt (int pos, int val)

Write an integer (4-byte) value to the page.

final long readLong (int pos)

Read a long (8-byte) value from the page.

final void writeLong (int pos, long val)

Write a long (8-byte) value to the page.

final void takeData (Page p)

Move the contents of the other page to this page, and zero out the other page.

void clear ()

Zero this page.

String signature ()

Static Public Member Functions

String signature (byte[] buf)

String signature (byte[] buf, int off, int cnt)

void main (String args[])

Package Functions

void init ()

Private Attributes

byte[] buf

Member Function Documentation

void com.quadcap.sql.file.Block.clear ( )

Zero this page.

Implements com.quadcap.sql.file.Page.
Definition at line 327 of file Block.java.
References com.quadcap.sql.file.Block.buf.
Referenced by com.quadcap.sql.file.BlockFile.newPage().

final void com.quadcap.sql.file.Block.flush ( ) throws IOException

Write the contents of the buffer back to the underlying store.

Reimplemented from com.quadcap.sql.file.Cacheable.
Definition at line 86 of file Block.java.
References com.quadcap.sql.file.Block.buf, com.quadcap.sql.file.Block.getPageNum(), and com.quadcap.sql.file.BlockStore.write().

final Object com.quadcap.sql.file.Block.getData ( ) [virtual]

From the Cacheable class, return the underlying data object.
When used as a Block, we typically use the read() and write methods to access the underlying data...
Implements com.quadcap.sql.file.Cacheable.
Definition at line 109 of file Block.java.
References com.quadcap.sql.file.Block.buf.
Referenced by com.quadcap.sql.index.Bnode.moveKeys().

byte [] com.quadcap.sql.file.Block.getDataAndReset ( )

Return a reference to the array containing the data for this block, and create a new buffer, so that the reference returned can be used in a subsequent setData call to another buffer.
This allows the contents of one block to be moved to another block with a minimum of array copying.
Definition at line 118 of file Block.java.
References com.quadcap.sql.file.Block.buf.
Referenced by com.quadcap.sql.file.BlockFile.freePage(), and com.quadcap.sql.file.Block.takeData().

long com.quadcap.sql.file.Block.getPageNum ( )

Return this page's block number.

Implements com.quadcap.sql.file.Page.
Definition at line 58 of file Block.java.
Referenced by com.quadcap.sql.index.Bnode.checkMagic(), com.quadcap.sql.index.Bnode.display(), com.quadcap.sql.file.Block.flush(), com.quadcap.sql.index.Bnode.free(), com.quadcap.sql.file.Block.init(), and com.quadcap.sql.index.Bnode.propogateSplit().

void com.quadcap.sql.file.Block.init ( ) [package]

Definition at line 334 of file Block.java.
References com.quadcap.sql.file.Block.buf.

void com.quadcap.sql.file.Block.init ( Object store,

long key

) throws IOException

Initialize this block.
Create the buffer if necessary, and initialize the buffer contents from the underlying store. We assume that the BlockStore.read() method will fill the buffer with zeros if we're attempting to "read" a block that doesn't exist yet.

Parameters:

store the underlying BlockStore which manages the blocks.

key an Integer specifying the block number.

Reimplemented from com.quadcap.sql.file.Cacheable.
Definition at line 70 of file Block.java.
References com.quadcap.sql.file.BlockStore.blockSize, com.quadcap.sql.file.Block.buf, com.quadcap.sql.file.Block.getPageNum(), and com.quadcap.sql.file.BlockStore.read().
Referenced by com.quadcap.sql.file.Block.main().

void com.quadcap.sql.file.Block.main ( String args[] ) [static]

Definition at line 359 of file Block.java.
References com.quadcap.sql.file.Block.init(), com.quadcap.sql.file.Block.main(), com.quadcap.sql.file.Block.read(), com.quadcap.sql.file.Block.readInt(), and com.quadcap.sql.file.Block.writeInt().
Referenced by com.quadcap.sql.file.Block.main().

final int com.quadcap.sql.file.Block.read ( int pos,

byte[] pbuf,

int offset,

int len

)

Read a range of bytes from the page.

Parameters:

pos the offset in the page of the first byte to read

pbuf the buffer into which the bytes are placed.

offset the offset in pbuf where the first byte is placed.

len the number of bytes to read

Implements com.quadcap.sql.file.Page.
Definition at line 168 of file Block.java.
References com.quadcap.sql.file.Block.buf, and com.quadcap.sql.file.Block.read().
Referenced by com.quadcap.sql.index.Bnode.dataAtPos(), com.quadcap.sql.file.BlockFile.dump(), com.quadcap.sql.index.Bnode.getBytes(), com.quadcap.sql.file.BlockFile.getBytes(), com.quadcap.sql.index.Bnode.keyAtPos(), com.quadcap.sql.file.Block.main(), com.quadcap.sql.file.SubPage.read(), and com.quadcap.sql.file.Block.read().

final byte com.quadcap.sql.file.Block.readByte ( int pos )

Definition at line 208 of file Block.java.
References com.quadcap.sql.file.Block.buf, and com.quadcap.sql.file.Block.readByte().
Referenced by com.quadcap.sql.file.BlockFile.dump(), com.quadcap.sql.index.Bnode.getBytes(), com.quadcap.sql.index.Bnode.getKeyEnd(), com.quadcap.sql.index.Bnode.getKeyLen(), com.quadcap.sql.index.Bnode.longDataAtPos(), and com.quadcap.sql.file.Block.readByte().

final int com.quadcap.sql.file.Block.readInt ( int pos )

Read an integer (4-byte) value from the page.

Parameters:

pos the offset in the page of the integer.

Implements com.quadcap.sql.file.Page.
Definition at line 264 of file Block.java.
References com.quadcap.sql.file.Block.buf, and com.quadcap.sql.file.Block.readInt().
Referenced by com.quadcap.sql.file.BlockFile.dump(), com.quadcap.sql.index.Bnode.getBos(), com.quadcap.sql.index.Bnode.getCount(), com.quadcap.sql.index.Bnode.getFlags(), com.quadcap.sql.index.Bnode.getGarbage(), com.quadcap.sql.file.Block.main(), com.quadcap.sql.file.SubPage.readInt(), and com.quadcap.sql.file.Block.readInt().

final short com.quadcap.sql.file.Block.readShort ( int pos )

Read a short (2-byte) value from the page.

Parameters:

pos the offset in the page of the short.

Definition at line 232 of file Block.java.
References com.quadcap.sql.file.Block.buf, and com.quadcap.sql.file.Block.readShort().
Referenced by com.quadcap.sql.file.BlockFile.dump(), com.quadcap.sql.index.Bnode.getKeyIndex(), and com.quadcap.sql.file.Block.readShort().

void com.quadcap.sql.file.Block.setData ( Object obj ) [virtual]

From the Cacheable class, set the underlying data object.
When used as a Block, we typically use the read() and write methods to access the underlying data...
Implements com.quadcap.sql.file.Cacheable.
Definition at line 135 of file Block.java.
References com.quadcap.sql.file.Block.buf, and com.quadcap.sql.file.Block.setData().
Referenced by com.quadcap.sql.file.Block.setData().

String com.quadcap.sql.file.Block.signature ( byte[] buf,

int off,

int cnt

) [static]

Definition at line 346 of file Block.java.

String com.quadcap.sql.file.Block.signature ( byte[] buf ) [static]

Definition at line 343 of file Block.java.
References com.quadcap.sql.file.Block.signature().

String com.quadcap.sql.file.Block.signature ( )

Definition at line 339 of file Block.java.
References com.quadcap.sql.file.Block.buf.
Referenced by com.quadcap.sql.file.BlockFile.signature(), and com.quadcap.sql.file.Block.signature().

final void com.quadcap.sql.file.Block.takeData ( Page p )

Move the contents of the other page to this page, and zero out the other page.

Implements com.quadcap.sql.file.Page.
Definition at line 323 of file Block.java.
References com.quadcap.sql.file.Block.getDataAndReset(), and com.quadcap.sql.file.Block.takeData().
Referenced by com.quadcap.sql.index.Bnode.propogateSplit(), and com.quadcap.sql.file.Block.takeData().

String com.quadcap.sql.file.Block.toString ( )

Only a debugging version implemented so far...

Definition at line 152 of file Block.java.
References com.quadcap.sql.file.Cacheable.getKey().

final int com.quadcap.sql.file.Block.write ( int pos,

byte[] pbuf,

int offset,

int len

)

Write a range of bytes to the page.

Parameters:

pos the offset in the page of the first byte to write

pbuf the buffer from which the bytes are obtained

offset the offset in pbuf of the first byte to write

len the number of bytes to write

Implements com.quadcap.sql.file.Page.
Definition at line 196 of file Block.java.
References com.quadcap.sql.file.Block.buf, and com.quadcap.sql.file.Block.write().
Referenced by com.quadcap.sql.index.Bnode.insertKeyData(), com.quadcap.sql.file.BlockFile.putBytes(), com.quadcap.sql.file.BlockFile.updateBytes(), com.quadcap.sql.file.SubPage.write(), and com.quadcap.sql.file.Block.write().

final void com.quadcap.sql.file.Block.writeByte ( int pos,

byte val

)

Definition at line 217 of file Block.java.
References com.quadcap.sql.file.Block.buf, and com.quadcap.sql.file.Block.writeByte().
Referenced by com.quadcap.sql.file.Block.writeByte(), and com.quadcap.sql.index.Bnode.writeLenLen().

final void com.quadcap.sql.file.Block.writeInt ( int pos,

int val

)

Write an integer (4-byte) value to the page.

Parameters:

pos the offset in the page of the integer.

val the integer value to write.

Implements com.quadcap.sql.file.Page.
Definition at line 280 of file Block.java.
References com.quadcap.sql.file.Block.buf, and com.quadcap.sql.file.Block.writeInt().
Referenced by com.quadcap.sql.file.Block.main(), com.quadcap.sql.index.Bnode.setBos(), com.quadcap.sql.index.Bnode.setCount(), com.quadcap.sql.index.Bnode.setFlags(), com.quadcap.sql.index.Bnode.setGarbage(), com.quadcap.sql.file.SubPage.writeInt(), and com.quadcap.sql.file.Block.writeInt().

final void com.quadcap.sql.file.Block.writeShort ( int pos,

short val

)

Write a short (2-byte) value to the page.

Parameters:

pos the offset in the page of the short.

val the short value to write.

Definition at line 248 of file Block.java.
References com.quadcap.sql.file.Block.buf, and com.quadcap.sql.file.Block.writeShort().
Referenced by com.quadcap.sql.index.Bnode.setKeyIndex(), and com.quadcap.sql.file.Block.writeShort().

Member Data Documentation


Public Member Functions
long	getPageNum ()
	Return this page's block number.
void	init (Object store, long key) throws IOException
	Initialize this block.
final void	flush () throws IOException
	Write the contents of the buffer back to the underlying store.
final Object	getData ()
	From the Cacheable class, return the underlying data object.
byte[]	getDataAndReset ()
	Return a reference to the array containing the data for this block, and create a new buffer, so that the reference returned can be used in a subsequent `setData` call to another buffer.
void	setData (Object obj)
	From the Cacheable class, set the underlying data object.
String	toString ()
	Only a debugging version implemented so far...
final int	read (int pos, byte[] pbuf, int offset, int len)
	Read a range of bytes from the page.
final int	write (int pos, byte[] pbuf, int offset, int len)
	Write a range of bytes to the page.
final byte	readByte (int pos)
final void	writeByte (int pos, byte val)
final short	readShort (int pos)
	Read a short (2-byte) value from the page.
final void	writeShort (int pos, short val)
	Write a short (2-byte) value to the page.
final int	readInt (int pos)
	Read an integer (4-byte) value from the page.
final void	writeInt (int pos, int val)
	Write an integer (4-byte) value to the page.
final long	readLong (int pos)
	Read a long (8-byte) value from the page.
final void	writeLong (int pos, long val)
	Write a long (8-byte) value to the page.
final void	takeData (Page p)
	Move the contents of the other page to this page, and zero out the other page.
void	clear ()
	Zero this page.
String	signature ()
Static Public Member Functions
String	signature (byte[] buf)
String	signature (byte[] buf, int off, int cnt)
void	main (String args[])
Package Functions
void	init ()
Private Attributes
byte[]	buf