index
Class SortedPage

java.lang.Object
  global.Page
      index.SortedPage

All Implemented Interfaces:

GlobalConst

Direct Known Subclasses:

HashBucket

 class SortedPage
extends Page

A base class for index pages that automatically stores records in ascending order by key value. SortedPage supports variable-length records by using a slot directory, with the slots at the front and the records in the back, both growing and shrinking into and from the free space in the middle of the page.

Field Summary

Fields inherited from class global.Page

data

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

SortedPage()
Default constructor; creates a sorted page with default values.

SortedPage(Page page)
Constructor that wraps an existing sorted page.

Method Summary

boolean	deleteEntry(DataEntry entry) Deletes a record from the page, compacting the free space (including the slot directory).
int	findEntry(SearchKey key) Searches for the first entry that matches the given search key.
DataEntry	getEntryAt(int slotno) Gets the entry at the given slot number.
short	getEntryCount() Gets the number of entries on the page.
SearchKey	getFirstKey() Gets the key of the first entry on the page.
short	getFreeSpace() Gets the amount of free space (in bytes).
SearchKey	getKeyAt(int slotno) Gets the key at the given slot number.
PageId	getNextPage() Gets the next page's id.
boolean	insertEntry(DataEntry entry) Inserts a new record into the page in sorted order.
int	nextEntry(SearchKey key, int slotno) Searches for the next entry that matches the given search key, and stored after the given slot.
void	setNextPage(PageId pageno) Sets the next page's id.

Methods inherited from class global.Page

copyPage, getCharValue, getData, getFloatValue, getIntValue, getShortValue, getStringValue, setCharValue, setData, setFloatValue, setIntValue, setPage, setShortValue, setStringValue

Methods inherited from class java.lang.Object

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

Constructor Detail

SortedPage

public SortedPage()

Default constructor; creates a sorted page with default values.

SortedPage

public SortedPage(Page page)

Constructor that wraps an existing sorted page.

Method Detail

getEntryCount

public short getEntryCount()

Gets the number of entries on the page.

getFreeSpace

public short getFreeSpace()

Gets the amount of free space (in bytes).

getNextPage

public PageId getNextPage()

Gets the next page's id.

setNextPage

public void setNextPage(PageId pageno)

Sets the next page's id.

getEntryAt

public DataEntry getEntryAt(int slotno)

Gets the entry at the given slot number.

Throws:

java.lang.IllegalArgumentException - if the slot number is invalid

getKeyAt

public SearchKey getKeyAt(int slotno)

Gets the key at the given slot number.

Throws:

java.lang.IllegalArgumentException - if the slot number is invalid

getFirstKey

public SearchKey getFirstKey()

Gets the key of the first entry on the page.

Throws:

java.lang.IllegalStateException - if the page is empty

insertEntry

public boolean insertEntry(DataEntry entry)

Inserts a new record into the page in sorted order.

Returns:

true if inserting made this page dirty, false otherwise

Throws:

java.lang.IllegalStateException - if insufficient space

deleteEntry

public boolean deleteEntry(DataEntry entry)

Deletes a record from the page, compacting the free space (including the slot directory).

Returns:

true if deleting made this page dirty, false otherwise

Throws:

java.lang.IllegalArgumentException - if the entry doesn't exist

findEntry

public int findEntry(SearchKey key)

Searches for the first entry that matches the given search key.

Returns:

the slot number of the entry, or -1 if not found

nextEntry

public int nextEntry(SearchKey key,
                     int slotno)

Searches for the next entry that matches the given search key, and stored after the given slot.

Returns:

the slot number of the entry, or -1 if not found