com.healthmarketscience.jackcess.impl

Class UsageMap

java.lang.Object

com.healthmarketscience.jackcess.impl.UsageMap

public class UsageMap
extends java.lang.Object

Describes which database pages a particular table uses

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private class	UsageMap.Handler
private class	UsageMap.InlineHandler Usage map whose map is written inline in the same page.
class	UsageMap.PageCursor Utility class to traverse over the pages in the UsageMap.
private class	UsageMap.ReferenceHandler Usage map whose map is written across one or more entire separate pages of page type USAGE_MAP.

Field Summary

Fields

Modifier and Type	Field and Description
private DatabaseImpl	_database owning database
private int	_endPage Last page that this usage map applies to
private UsageMap.Handler	_handler the current handler implementation for reading/writing the specific usage map type.
private int	_modCount modification count on the usage map, used to keep the cursors in sync
private java.util.BitSet	_pageNumbers bits representing page numbers used, offset from _startPage
private short	_rowStart Offset of the data page at which the usage map declaration starts
private int	_startOffset Offset of the data page at which the usage map data starts
private int	_startPage First page that this usage map applies to
private java.nio.ByteBuffer	_tableBuffer Buffer that contains the usage map table declaration page
private int	_tablePageNum Page number of the map table declaration
private static int	INVALID_BIT_INDEX bit index value for an invalid page number
static byte	MAP_TYPE_INLINE Inline map type
static byte	MAP_TYPE_REFERENCE Reference map type, for maps that are too large to fit inline
(package private) static java.lang.String	MSG_PREFIX_UNRECOGNIZED_MAP Error message prefix used when map type is unrecognized.

Constructor Summary

Constructors

Modifier	Constructor and Description
private	UsageMap(DatabaseImpl database, java.nio.ByteBuffer tableBuffer, int pageNum, short rowStart)

Method Summary

Modifier and Type	Method and Description
void	addPageNumber(int pageNumber) Add a page number to this usage map
protected int	bitIndexToPageNumber(int bitIndex, int invalidPageNumber)
protected void	clearTableAndPages()
boolean	containsPageNumber(int pageNumber) Determines if the given page number is contained in this map.
UsageMap.PageCursor	cursor()
DatabaseImpl	getDatabase()
protected int	getEndPage()
protected int	getFirstPageNumber()
JetFormat	getFormat()
protected int	getLastPageNumber()
protected int	getNextBitIndex(int curIndex)
protected int	getNextPageNumber(int curPage)
PageChannel	getPageChannel()
int	getPageCount()
protected java.util.BitSet	getPageNumbers()
protected int	getPrevBitIndex(int curIndex)
protected int	getPrevPageNumber(int curPage)
protected int	getRowEnd()
protected short	getRowStart()
protected int	getStartOffset()
protected int	getStartPage()
protected java.nio.ByteBuffer	getTableBuffer()
protected int	getTablePageNumber()
private void	initHandler(byte mapType, boolean assumeOutOfRangeBitsOn)
protected boolean	isPageWithinRange(int pageNumber)
protected int	pageNumberToBitIndex(int pageNumber)
protected void	processMap(java.nio.ByteBuffer buffer, int bufferStartPage) Read in the page numbers in this inline map
private void	promoteInlineHandlerToReferenceHandler(int newPageNumber) Promotes and inline usage map to a reference usage map.
private static void	rangeToString(java.util.List<java.lang.String> ranges, int rangeStart, int rangeEnd)
static UsageMap	read(DatabaseImpl database, java.nio.ByteBuffer buf, boolean assumeOutOfRangeBitsOn)
static UsageMap	read(DatabaseImpl database, int pageNum, int rowNum, boolean assumeOutOfRangeBitsOn)
private void	reAddPages(int oldStartPage, java.util.BitSet oldPageNumbers, int newPageNumber)
protected void	removePageNumber(int pageNumber, boolean force) Remove a page number from this usage map
protected void	setPageRange(int newStartPage, int newEndPage)
protected void	setStartOffset(int startOffset)
java.lang.String	toString()
protected void	updateMap(int absolutePageNumber, int bufferRelativePageNumber, java.nio.ByteBuffer buffer, boolean add, boolean force)
protected void	writeTable()

Methods inherited from class java.lang.Object

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

Field Detail

MAP_TYPE_INLINE

public static final byte MAP_TYPE_INLINE

Inline map type

See Also:

Constant Field Values

MAP_TYPE_REFERENCE

public static final byte MAP_TYPE_REFERENCE

Reference map type, for maps that are too large to fit inline

See Also:

Constant Field Values

INVALID_BIT_INDEX

private static final int INVALID_BIT_INDEX

bit index value for an invalid page number

See Also:

Constant Field Values

_database

private final DatabaseImpl _database

owning database

_tablePageNum

private final int _tablePageNum

Page number of the map table declaration

_startOffset

private int _startOffset

Offset of the data page at which the usage map data starts

_rowStart

private final short _rowStart

Offset of the data page at which the usage map declaration starts

_startPage

private int _startPage

First page that this usage map applies to

_endPage

private int _endPage

Last page that this usage map applies to

_pageNumbers

private java.util.BitSet _pageNumbers

bits representing page numbers used, offset from _startPage

_tableBuffer

private final java.nio.ByteBuffer _tableBuffer

Buffer that contains the usage map table declaration page

_modCount

private int _modCount

modification count on the usage map, used to keep the cursors in sync

_handler

private UsageMap.Handler _handler

the current handler implementation for reading/writing the specific usage map type. note, this may change over time.

MSG_PREFIX_UNRECOGNIZED_MAP

static final java.lang.String MSG_PREFIX_UNRECOGNIZED_MAP

Error message prefix used when map type is unrecognized.

See Also:

Constant Field Values

Constructor Detail

UsageMap

private UsageMap(DatabaseImpl database,
                 java.nio.ByteBuffer tableBuffer,
                 int pageNum,
                 short rowStart)
          throws java.io.IOException

Parameters:

database - database that contains this usage map

tableBuffer - Buffer that contains this map's declaration

pageNum - Page number that this usage map is contained in

rowStart - Offset at which the declaration starts in the buffer

Throws:

java.io.IOException

Method Detail

getDatabase

public DatabaseImpl getDatabase()

getFormat

public JetFormat getFormat()

getPageChannel

public PageChannel getPageChannel()

read

public static UsageMap read(DatabaseImpl database,
                            java.nio.ByteBuffer buf,
                            boolean assumeOutOfRangeBitsOn)
                     throws java.io.IOException

Parameters:

database - database that contains this usage map

buf - buffer which contains the usage map row info

Returns:

Either an InlineUsageMap or a ReferenceUsageMap, depending on which type of map is found

Throws:

java.io.IOException

read

public static UsageMap read(DatabaseImpl database,
                            int pageNum,
                            int rowNum,
                            boolean assumeOutOfRangeBitsOn)
                     throws java.io.IOException

Parameters:

database - database that contains this usage map

pageNum - Page number that this usage map is contained in

rowNum - Number of the row on the page that contains this usage map

Returns:

Either an InlineUsageMap or a ReferenceUsageMap, depending on which type of map is found

Throws:

java.io.IOException

initHandler

private void initHandler(byte mapType,
                         boolean assumeOutOfRangeBitsOn)
                  throws java.io.IOException

Throws:

java.io.IOException

cursor

public UsageMap.PageCursor cursor()

getPageCount

public int getPageCount()

getRowStart

protected short getRowStart()

getRowEnd

protected int getRowEnd()

setStartOffset

protected void setStartOffset(int startOffset)

getStartOffset

protected int getStartOffset()

getTableBuffer

protected java.nio.ByteBuffer getTableBuffer()

getTablePageNumber

protected int getTablePageNumber()

getStartPage

protected int getStartPage()

getEndPage

protected int getEndPage()

getPageNumbers

protected java.util.BitSet getPageNumbers()

setPageRange

protected void setPageRange(int newStartPage,
                            int newEndPage)

isPageWithinRange

protected boolean isPageWithinRange(int pageNumber)

getFirstPageNumber

protected int getFirstPageNumber()

getNextPageNumber

protected int getNextPageNumber(int curPage)

getNextBitIndex

protected int getNextBitIndex(int curIndex)

getLastPageNumber

protected int getLastPageNumber()

getPrevPageNumber

protected int getPrevPageNumber(int curPage)

getPrevBitIndex

protected int getPrevBitIndex(int curIndex)

bitIndexToPageNumber

protected int bitIndexToPageNumber(int bitIndex,
                                   int invalidPageNumber)

pageNumberToBitIndex

protected int pageNumberToBitIndex(int pageNumber)

clearTableAndPages

protected void clearTableAndPages()

writeTable

protected void writeTable()
                   throws java.io.IOException

Throws:

java.io.IOException

processMap

protected void processMap(java.nio.ByteBuffer buffer,
                          int bufferStartPage)

Read in the page numbers in this inline map

containsPageNumber

public boolean containsPageNumber(int pageNumber)

Determines if the given page number is contained in this map.

addPageNumber

public void addPageNumber(int pageNumber)
                   throws java.io.IOException

Add a page number to this usage map

Throws:

java.io.IOException

removePageNumber

protected void removePageNumber(int pageNumber,
                                boolean force)
                         throws java.io.IOException

Remove a page number from this usage map

Throws:

java.io.IOException

updateMap

protected void updateMap(int absolutePageNumber,
                         int bufferRelativePageNumber,
                         java.nio.ByteBuffer buffer,
                         boolean add,
                         boolean force)
                  throws java.io.IOException

Throws:

java.io.IOException

promoteInlineHandlerToReferenceHandler

private void promoteInlineHandlerToReferenceHandler(int newPageNumber)
                                             throws java.io.IOException

Promotes and inline usage map to a reference usage map.

Throws:

java.io.IOException

reAddPages

private void reAddPages(int oldStartPage,
                        java.util.BitSet oldPageNumbers,
                        int newPageNumber)
                 throws java.io.IOException

Throws:

java.io.IOException

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

rangeToString

private static void rangeToString(java.util.List<java.lang.String> ranges,
                                  int rangeStart,
                                  int rangeEnd)