index
Class HashScan

java.lang.Object
  index.HashScan

All Implemented Interfaces:

GlobalConst

public class HashScan
extends java.lang.Object
implements GlobalConst

A HashScan object is created only through the function openScan() in the HashIndex class. It supports the getNext interface which will simply retrieve the next record in the file.

Field Summary

Fields inherited from interface global.GlobalConst

EMPTY_SLOT, FIRST_PAGEID, INVALID_PAGEID, MAX_COLSIZE, MAX_TUPSIZE, NAME_MAXLEN, PAGE_SIZE, PIN_DISKIO, PIN_MEMCPY, UNPIN_CLEAN, UNPIN_DIRTY

Constructor Summary

protected

HashScan(HashIndex index, SearchKey key) Constructs an equality scan by initializing the iterator state.

Method Summary

void	close() Closes the index scan, releasing any pinned pages.
protected void	finalize() Called by the garbage collector when there are no more references to the object; closes the scan if it's still open.
RID	getNext() Gets the next entry's record in the index scan.
boolean	hasNext() Returns true if there are more entries to scan, false otherwise.

Methods inherited from class java.lang.Object

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

Constructor Detail

HashScan

protected HashScan(HashIndex index,
                   SearchKey key)

Constructs an equality scan by initializing the iterator state.

Method Detail

finalize

protected void finalize()
                 throws java.lang.Throwable

Called by the garbage collector when there are no more references to the object; closes the scan if it's still open.

Overrides:

finalize in class java.lang.Object

Throws:

java.lang.Throwable

close

public void close()

Closes the index scan, releasing any pinned pages.

hasNext

public boolean hasNext()

Returns true if there are more entries to scan, false otherwise.

getNext

public RID getNext()

Gets the next entry's record in the index scan.

Throws:

java.lang.IllegalStateException - if the scan has no more entries