btree
Class BTFileScan

java.lang.Object
  btree.IndexFileScan
      btree.BTFileScan

All Implemented Interfaces:

GlobalConst

public class BTFileScan

extends IndexFileScan

implements GlobalConst

BTFileScan implements a search/iterate interface to B+ tree index files (class BTreeFile). It derives from abstract base class IndexFileScan.

Field Summary

Fields inherited from interface global.GlobalConst

INVALID_PAGE, MAX_NAME, MAX_SPACE, MAXATTRNAME, MAXFILENAME, MAXINDEXNAME, MINIBASE_BUFFER_POOL_SIZE, MINIBASE_DB_SIZE, MINIBASE_DEFAULT_SHAREDMEM_SIZE, MINIBASE_MAX_TRANSACTIONS, MINIBASE_MAXARRSIZE, MINIBASE_PAGESIZE, NUMBUF

Constructor Summary

BTFileScan()

Method Summary

void	delete_current() Delete currently-being-scanned(i.e., just scanned) data entry.
void	DestroyBTreeFileScan() destructor.
KeyDataEntry	get_next() Iterate once (during a scan).
int	keysize() max size of the key

Methods inherited from class java.lang.Object

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

Constructor Detail

BTFileScan

public BTFileScan()

Method Detail

get_next

public KeyDataEntry get_next()
                      throws ScanIteratorException

Iterate once (during a scan).

Specified by:

get_next in class IndexFileScan

Returns:

null if done; otherwise next KeyDataEntry

Throws:

ScanIteratorException - iterator error

delete_current

public void delete_current()
                    throws ScanDeleteException

Delete currently-being-scanned(i.e., just scanned) data entry.

Specified by:

delete_current in class IndexFileScan

Throws:

ScanDeleteException - delete error when scan

keysize

public int keysize()

max size of the key

Specified by:

keysize in class IndexFileScan

Returns:

the maxumum size of the key in BTFile

DestroyBTreeFileScan

public void DestroyBTreeFileScan()
                          throws java.io.IOException,
                                 InvalidFrameNumberException,
                                 ReplacerException,
                                 PageUnpinnedException,
                                 HashEntryNotFoundException

destructor. unpin some pages if they are not unpinned already. and do some clearing work.

Throws:

java.io.IOException - error from the lower layer

InvalidFrameNumberException - error from the lower layer

ReplacerException - error from the lower layer

PageUnpinnedException - error from the lower layer

HashEntryNotFoundException - error from the lower layer