heap
Class HFPage

java.lang.Object
  diskmgr.Page
      heap.HFPage

All Implemented Interfaces:

heap.ConstSlot, GlobalConst

Direct Known Subclasses:

BTSortedPage

public class HFPage

extends Page

implements heap.ConstSlot, GlobalConst

Class heap file page. The design assumes that records are kept compacted when deletions are performed.

Field Summary

static int	CUR_PAGE
static int	DPFIXED
static int	EMPTY_SLOT
static int	FREE_SPACE
static int	INVALID_SLOT
static int	NEXT_PAGE
static int	PREV_PAGE
static int	SIZE_OF_SLOT
static int	SLOT_CNT
static int	TYPE
static int	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

HFPage()
Default constructor

HFPage(Page page)
Constructor of class HFPage open a HFPage and make this HFpage piont to the given page

Method Summary

int	available_space() returns the amount of available space on the page.
void	deleteRecord(RID rid) delete the record with the specified rid
void	dumpPage() Dump contents of a page
boolean	empty() Determining if the page is empty
RID	firstRecord()
PageId	getCurPage()
byte[]	getHFpageArray()
PageId	getNextPage()
PageId	getPrevPage()
Tuple	getRecord(RID rid) copies out record with RID rid into record pointer.
short	getSlotCnt()
short	getSlotLength(int slotno)
short	getSlotOffset(int slotno)
short	getType()
void	init(PageId pageNo, Page apage) Constructor of class HFPage initialize a new page
RID	insertRecord(byte[] record) inserts a new record onto the page, returns RID of this record
RID	nextRecord(RID curRid)
void	openHFpage(Page apage) Constructor of class HFPage open a existed hfpage
Tuple	returnRecord(RID rid) returns a tuple in a byte array[pageSize] with given RID rid.
void	setCurPage(PageId pageNo) sets value of curPage to pageNo
void	setNextPage(PageId pageNo) sets value of nextPage to pageNo
void	setPrevPage(PageId pageNo) sets value of prevPage to pageNo
void	setSlot(int slotno, int length, int offset) sets slot contents
void	setType(short valtype) sets value of type

Methods inherited from class diskmgr.Page

getpage, setpage

Methods inherited from class java.lang.Object

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

Field Detail

SIZE_OF_SLOT

public static final int SIZE_OF_SLOT

See Also:

Constant Field Values

DPFIXED

public static final int DPFIXED

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Constant Field Values

SLOT_CNT

public static final int SLOT_CNT

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Constant Field Values

USED_PTR

public static final int USED_PTR

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Constant Field Values

FREE_SPACE

public static final int FREE_SPACE

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Constant Field Values

TYPE

public static final int TYPE

See Also:

Constant Field Values

PREV_PAGE

public static final int PREV_PAGE

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Constant Field Values

NEXT_PAGE

public static final int NEXT_PAGE

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Constant Field Values

CUR_PAGE

public static final int CUR_PAGE

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Constant Field Values

INVALID_SLOT

public static final int INVALID_SLOT

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Constant Field Values

EMPTY_SLOT

public static final int EMPTY_SLOT

See Also:

Constant Field Values

Constructor Detail

HFPage

public HFPage()

Default constructor

HFPage

public HFPage(Page page)

Constructor of class HFPage open a HFPage and make this HFpage piont to the given page

Parameters:

page - the given page in Page type

Method Detail

openHFpage

public void openHFpage(Page apage)

Constructor of class HFPage open a existed hfpage

Parameters:

apage - a page in buffer pool

init

public void init(PageId pageNo,
                 Page apage)
          throws java.io.IOException

Constructor of class HFPage initialize a new page

Parameters:

pageNo - the page number of a new page to be initialized

apage - the Page to be initialized

Throws:

java.io.IOException - I/O errors

See Also:

Page

getHFpageArray

public byte[] getHFpageArray()

Returns:

byte array

dumpPage

public void dumpPage()
              throws java.io.IOException

Dump contents of a page

Throws:

java.io.IOException - I/O errors

getPrevPage

public PageId getPrevPage()
                   throws java.io.IOException

Returns:

PageId of previous page

Throws:

java.io.IOException - I/O errors

setPrevPage

public void setPrevPage(PageId pageNo)
                 throws java.io.IOException

sets value of prevPage to pageNo

Parameters:

pageNo - page number for previous page

Throws:

java.io.IOException - I/O errors

getNextPage

public PageId getNextPage()
                   throws java.io.IOException

Returns:

page number of next page

Throws:

java.io.IOException - I/O errors

setNextPage

public void setNextPage(PageId pageNo)
                 throws java.io.IOException

sets value of nextPage to pageNo

Parameters:

pageNo - page number for next page

Throws:

java.io.IOException - I/O errors

getCurPage

public PageId getCurPage()
                  throws java.io.IOException

Returns:

page number of current page

Throws:

java.io.IOException - I/O errors

setCurPage

public void setCurPage(PageId pageNo)
                throws java.io.IOException

sets value of curPage to pageNo

Parameters:

pageNo - page number for current page

Throws:

java.io.IOException - I/O errors

getType

public short getType()
              throws java.io.IOException

Returns:

the ype

Throws:

java.io.IOException - I/O errors

setType

public void setType(short valtype)
             throws java.io.IOException

sets value of type

Parameters:

valtype - an arbitrary value

Throws:

java.io.IOException - I/O errors

getSlotCnt

public short getSlotCnt()
                 throws java.io.IOException

Returns:

slotCnt used in this page

Throws:

java.io.IOException - I/O errors

setSlot

public void setSlot(int slotno,
                    int length,
                    int offset)
             throws java.io.IOException

sets slot contents

Parameters:

slotno - the slot number

length - length of record the slot contains

offset - offset of record

Throws:

java.io.IOException - I/O errors

getSlotLength

public short getSlotLength(int slotno)
                    throws java.io.IOException

Parameters:

slotno - slot number

Returns:

the length of record the given slot contains

Throws:

java.io.IOException - I/O errors

getSlotOffset

public short getSlotOffset(int slotno)
                    throws java.io.IOException

Parameters:

slotno - slot number

Returns:

the offset of record the given slot contains

Throws:

java.io.IOException - I/O errors

insertRecord

public RID insertRecord(byte[] record)
                 throws java.io.IOException

inserts a new record onto the page, returns RID of this record

Parameters:

record - a record to be inserted

Returns:

RID of record, null if sufficient space does not exist

Throws:

java.io.IOException - I/O errors in C++ Status insertRecord(char *recPtr, int recLen, RID& rid)

deleteRecord

public void deleteRecord(RID rid)
                  throws java.io.IOException,
                         InvalidSlotNumberException

delete the record with the specified rid

Parameters:

rid - the record ID

Throws:

InvalidSlotNumberException - Invalid slot number

java.io.IOException - I/O errors in C++ Status deleteRecord(const RID& rid)

firstRecord

public RID firstRecord()
                throws java.io.IOException

Returns:

RID of first record on page, null if page contains no records.

Throws:

java.io.IOException - I/O errors in C++ Status firstRecord(RID& firstRid)

nextRecord

public RID nextRecord(RID curRid)
               throws java.io.IOException

Parameters:

curRid - current record ID

Returns:

RID of next record on the page, null if no more records exist on the page

Throws:

java.io.IOException - I/O errors in C++ Status nextRecord (RID curRid, RID& nextRid)

getRecord

public Tuple getRecord(RID rid)
                throws java.io.IOException,
                       InvalidSlotNumberException

copies out record with RID rid into record pointer.
Status getRecord(RID rid, char *recPtr, int& recLen)

Parameters:

rid - the record ID

Returns:

a tuple contains the record

Throws:

InvalidSlotNumberException - Invalid slot number

java.io.IOException - I/O errors

See Also:

Tuple

returnRecord

public Tuple returnRecord(RID rid)
                   throws java.io.IOException,
                          InvalidSlotNumberException

returns a tuple in a byte array[pageSize] with given RID rid.
in C++ Status returnRecord(RID rid, char*& recPtr, int& recLen)

Parameters:

rid - the record ID

Returns:

a tuple with its length and offset in the byte array

Throws:

InvalidSlotNumberException - Invalid slot number

java.io.IOException - I/O errors

See Also:

Tuple

available_space

public int available_space()
                    throws java.io.IOException

returns the amount of available space on the page.

Returns:

the amount of available space on the page

Throws:

java.io.IOException - I/O errors

empty

public boolean empty()
              throws java.io.IOException

Determining if the page is empty

Returns:

true if the HFPage is has no records in it, false otherwise

Throws:

java.io.IOException - I/O errors