jdbm.recman
Class PageHeader

java.lang.Object
  extended by jdbm.recman.PageHeader
All Implemented Interfaces:
BlockView

public class PageHeader
extends java.lang.Object
implements BlockView

This class represents a page header. It is the common superclass for all different page views. It contains the following information:

  1. 2 bytes: the short block type code
  2. 8 bytes: the long block id of the next block in the block list
  3. 8 bytes: the long block id of the previous block in the block list
The page header block view hence sees 18 bytes of page header data.


Field Summary
protected  BlockIo block
          the page header block this view is associated with
protected static short SIZE
          the size of this page header = 18 bytes
 
Constructor Summary
protected PageHeader(BlockIo block)
          Constructs a PageHeader object from a block
 
Method Summary
protected  void paranoiaMagicOk()
          For paranoia mode
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

SIZE

protected static final short SIZE
the size of this page header = 18 bytes

See Also:
Constant Field Values

block

protected BlockIo block
the page header block this view is associated with

Constructor Detail

PageHeader

protected PageHeader(BlockIo block)
Constructs a PageHeader object from a block

Parameters:
block - The block that contains the page header
Throws:
IOException - if the block is too short to keep the page header.
Method Detail

paranoiaMagicOk

protected void paranoiaMagicOk()
For paranoia mode



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