btree
Class BTLeafPage

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

All Implemented Interfaces:

heap.ConstSlot, GlobalConst

public class BTLeafPage

extends BTSortedPage

A BTLeafPage is a leaf page on a B+ tree. It holds abstract pairs; it doesn't know anything about the keys (their lengths or their types), instead relying on the abstract interface consisting of BT.java.

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

BTLeafPage(int keyType)
new a page, associate the BTLeafPage instance with the Page instance, also it sets the type to be NodeType.LEAF.

BTLeafPage(PageId pageno, int keyType)
pin the page with pageno, and get the corresponding BTLeafPage, also it sets the type to be NodeType.LEAF.

BTLeafPage(Page page, int keyType)
associate the BTLeafPage instance with the Page instance, also it sets the type to be NodeType.LEAF.

Method Summary

boolean	delEntry(KeyDataEntry dEntry) delete a data entry in the leaf page.
KeyDataEntry	getCurrent(RID rid) getCurrent returns the current record in the iteration; it is like getNext except it does not advance the iterator.
KeyDataEntry	getFirst(RID rid) Iterators.
KeyDataEntry	getNext(RID rid) Iterators.
RID	insertRecord(KeyClass key, RID dataRid) insertRecord READ THIS DESCRIPTION CAREFULLY.

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

BTLeafPage

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

pin the page with pageno, and get the corresponding BTLeafPage, also it sets the type to be NodeType.LEAF.

Parameters:

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

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

Throws:

java.io.IOException - error from the lower layer

ConstructPageException - BTLeafPage constructor error

BTLeafPage

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

associate the BTLeafPage instance with the Page instance, also it sets the type to be NodeType.LEAF.

Parameters:

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

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

Throws:

java.io.IOException - error from the lower layer

ConstructPageException - BTLeafPage constructor error

BTLeafPage

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

new a page, associate the BTLeafPage instance with the Page instance, also it sets the type to be NodeType.LEAF.

Parameters:

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

Throws:

java.io.IOException - error from the lower layer

ConstructPageException - BTLeafPage constructor error

Method Detail

insertRecord

public RID insertRecord(KeyClass key,
                        RID dataRid)
                 throws LeafInsertRecException

insertRecord READ THIS DESCRIPTION CAREFULLY. THERE ARE TWO RIDs WHICH MEAN TWO DIFFERENT THINGS. Inserts a key, rid value into the leaf node. This is accomplished by a call to SortedPage::insertRecord() Parameters:

Parameters:

key - - the key value of the data record. Input parameter.

dataRid - - the rid of the data record. This is stored on the leaf page along with the corresponding key value. Input parameter.

Returns:

- the rid of the inserted leaf record data entry, i.e., the pair.

Throws:

LeafInsertRecException - 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 BTLeafPage.

Parameters:

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

Returns:

return the first KeyDataEntry in the leaf page. null if no more record

Throws:

IteratorException - iterator error

getNext

public KeyDataEntry getNext(RID rid)
                     throws IteratorException

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

Parameters:

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

Returns:

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

Throws:

IteratorException - iterator error

getCurrent

public KeyDataEntry getCurrent(RID rid)
                        throws IteratorException

getCurrent returns the current record in the iteration; it is like getNext except it does not advance the iterator.

Parameters:

rid - the current rid. Input and Output parameter. But Output=Input.

Returns:

return the current KeyDataEntry

Throws:

IteratorException - iterator error

delEntry

public boolean delEntry(KeyDataEntry dEntry)
                 throws LeafDeleteException

delete a data entry in the leaf page.

Parameters:

dEntry - the entry will be deleted in the leaf page. Input parameter.

Returns:

true if deleted; false if no dEntry in the page

Throws:

LeafDeleteException - error when delete