btree
Class BTIndexPage

java.lang.Object
  diskmgr.Page
      heap.HFPage
          btree.BTSortedPage
              btree.BTIndexPage

All Implemented Interfaces:

heap.ConstSlot, GlobalConst

public class BTIndexPage

extends BTSortedPage

A BTIndexPage is an index page on a B+ tree. It holds abstract {key, PageId} pairs; it doesn't know anything about the keys (their lengths or their types), instead relying on the abstract interface in BT.java See those files for our {key,data} pairing interface and implementation.

Field Summary

Fields inherited from class heap.HFPage

CUR_PAGE, DPFIXED, EMPTY_SLOT, FREE_SPACE, INVALID_SLOT, NEXT_PAGE, PREV_PAGE, SIZE_OF_SLOT, SLOT_CNT, TYPE, USED_PTR

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

BTIndexPage(int keyType)

BTIndexPage(PageId pageno, int keyType)
pin the page with pageno, and get the corresponding BTIndexPage, also it sets the type of node to be NodeType.INDEX.

BTIndexPage(Page page, int keyType)
associate the BTIndexPage instance with the Page instance, also it sets the type of node to be NodeType.INDEX.

Method Summary

KeyDataEntry	getFirst(RID rid) Iterators.
KeyDataEntry	getNext(RID rid) Iterators.
RID	insertKey(KeyClass key, PageId pageNo) It inserts a value into the index page,

Methods inherited from class btree.BTSortedPage

deleteSortedRecord

Methods inherited from class heap.HFPage

available_space, deleteRecord, dumpPage, empty, firstRecord, getCurPage, getHFpageArray, getNextPage, getPrevPage, getRecord, getSlotCnt, getSlotLength, getSlotOffset, getType, init, insertRecord, nextRecord, openHFpage, returnRecord, setCurPage, setNextPage, setPrevPage, setSlot, setType

Methods inherited from class diskmgr.Page

getpage, setpage

Methods inherited from class java.lang.Object

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

Constructor Detail

BTIndexPage

public BTIndexPage(PageId pageno,
                   int keyType)
            throws java.io.IOException,
                   ConstructPageException

pin the page with pageno, and get the corresponding BTIndexPage, also it sets the type of node to be NodeType.INDEX.

Parameters:

pageno - Input parameter. To specify which page number the BTIndexPage will correspond to.

keyType - either AttrType.attrInteger or AttrType.attrString. Input parameter.

Throws:

java.io.IOException - error from the lower layer

ConstructPageException - error when BTIndexpage constructor

BTIndexPage

public BTIndexPage(Page page,
                   int keyType)
            throws java.io.IOException,
                   ConstructPageException

associate the BTIndexPage instance with the Page instance, also it sets the type of node to be NodeType.INDEX.

Parameters:

page - input parameter. To specify which page the BTIndexPage will correspond to.

keyType - either AttrType.attrInteger or AttrType.attrString. Input parameter.

Throws:

java.io.IOException - error from the lower layer

ConstructPageException - error when BTIndexpage constructor

BTIndexPage

public BTIndexPage(int keyType)
            throws java.io.IOException,
                   ConstructPageException

Method Detail

insertKey

public RID insertKey(KeyClass key,
                     PageId pageNo)
              throws IndexInsertRecException

It inserts a value into the index page,

Returns:

It returns the rid where the record is inserted; null if no space left.

Throws:

IndexInsertRecException - error when insert

getFirst

public KeyDataEntry getFirst(RID rid)
                      throws IteratorException

Iterators. One of the two functions: getFirst and getNext which provide an iterator interface to the records on a BTIndexPage.

Parameters:

rid - It will be modified and the first rid in the index page will be passed out by itself. Input and Output parameter.

Returns:

return the first KeyDataEntry in the index page. null if NO MORE RECORD

Throws:

IteratorException - iterator error

getNext

public KeyDataEntry getNext(RID rid)
                     throws IteratorException

Iterators. One of the two functions: get_first and get_next which provide an iterator interface to the records on a BTIndexPage.

Parameters:

rid - It will be modified and next rid will be passed out by itself. Input and Output parameter.

Returns:

return the next KeyDataEntry in the index page. null if no more record

Throws:

IteratorException - iterator error