com.healthmarketscience.jackcess
Class IndexData

java.lang.Object
  com.healthmarketscience.jackcess.IndexData

Direct Known Subclasses:

BigIndexData, SimpleIndexData

public abstract class IndexData
extends Object

Access table index data. This is the actual data which backs a logical Index, where one or more logical indexes can be backed by the same index data.

Author:

Tim McCune

Nested Class Summary

static class	IndexData.ColumnDescriptor Information about the columns in an index.
static class	IndexData.Entry A single leaf entry in an index (points to a single row)
class	IndexData.EntryCursor Utility class to traverse the entries in the Index.
static class	IndexData.EntryType type attributes for Entries which simplify comparisons

Field Summary

static IndexData.Entry	FIRST_ENTRY special entry which is less than any other entry
static IndexData.Entry	LAST_ENTRY special entry which is greater than any other entry
static Object	MAX_VALUE special object which will always be greater than any other value, when searching for an index entry range in a multi-value index
static Object	MIN_VALUE special object which will always be greater than any other value, when searching for an index entry range in a multi-value index

Method Summary

void	addRow(Object[] row, RowId rowId) Adds a row to this index
Object[]	constructIndexRow(Map<String,?> row) Constructs an array of values appropriate for this index from the given column values.
Object[]	constructIndexRow(String colName, Object value) Constructs an array of values appropriate for this index from the given column value.
Object[]	constructIndexRowFromEntry(Object... values) Constructs an array of values appropriate for this index from the given column values, expected to match the columns for this index.
static IndexData	create(Table table, ByteBuffer tableBuffer, int number, JetFormat format) Creates an IndexData appropriate for the given table, using information from the given table definition buffer.
IndexData.EntryCursor	cursor() Gets a new cursor for this index.
IndexData.EntryCursor	cursor(Object[] startRow, boolean startInclusive, Object[] endRow, boolean endInclusive) Gets a new cursor for this index, narrowed to the range defined by the given startRow and endRow.
void	deleteRow(Object[] row, RowId rowId) Removes a row from this index
List<IndexData.ColumnDescriptor>	getColumns() Returns the Columns for this index (unmodifiable)
JetFormat	getFormat()
int	getIndexDataNumber()
List<Index>	getIndexes()
byte	getIndexFlags()
int	getOwnedPageCount() Returns the number of database pages owned by this index data.
PageChannel	getPageChannel()
Index	getPrimaryIndex()
Table	getTable()
int	getUniqueEntryCount()
int	getUniqueEntryCountOffset()
void	initialize() Forces initialization of this index (actual parsing of index pages).
boolean	isInitialized() Whether or not the complete index state has been read.
boolean	isUnique() Whether or not index entries must be unique.
void	read(ByteBuffer tableBuffer, List<Column> availableColumns) Read the rest of the index info from a tableBuffer
boolean	shouldIgnoreNulls() Whether or not null values are actually recorded in the index.
String	toString()
void	update() Writes the current index state to the database.

Methods inherited from class java.lang.Object

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

Field Detail

FIRST_ENTRY

public static final IndexData.Entry FIRST_ENTRY

special entry which is less than any other entry

LAST_ENTRY

public static final IndexData.Entry LAST_ENTRY

special entry which is greater than any other entry

MAX_VALUE

public static final Object MAX_VALUE

special object which will always be greater than any other value, when searching for an index entry range in a multi-value index

MIN_VALUE

public static final Object MIN_VALUE

special object which will always be greater than any other value, when searching for an index entry range in a multi-value index

Method Detail

create

public static IndexData create(Table table,
                               ByteBuffer tableBuffer,
                               int number,
                               JetFormat format)
                        throws IOException

Creates an IndexData appropriate for the given table, using information from the given table definition buffer.

Throws:

IOException

getTable

public Table getTable()

getFormat

public JetFormat getFormat()

getPageChannel

public PageChannel getPageChannel()

getPrimaryIndex

public Index getPrimaryIndex()

Returns:

the "main" logical index which is backed by this data.

getIndexes

public List<Index> getIndexes()

Returns:

All of the Indexes backed by this data (unmodifiable List)

getIndexFlags

public byte getIndexFlags()

getIndexDataNumber

public int getIndexDataNumber()

getUniqueEntryCount

public int getUniqueEntryCount()

getUniqueEntryCountOffset

public int getUniqueEntryCountOffset()

shouldIgnoreNulls

public boolean shouldIgnoreNulls()

Whether or not null values are actually recorded in the index.

isUnique

public boolean isUnique()

Whether or not index entries must be unique.

Some notes about uniqueness:

• Access does not seem to consider multiple null entries invalid for a unique index
• text indexes collapse case, and Access seems to compare only the index entry bytes, therefore two strings which differ only in case will violate the unique constraint

getColumns

public List<IndexData.ColumnDescriptor> getColumns()

Returns the Columns for this index (unmodifiable)

isInitialized

public boolean isInitialized()

Whether or not the complete index state has been read.

getOwnedPageCount

public int getOwnedPageCount()

Returns the number of database pages owned by this index data.

Usage:

Intermediate: This method requires moderate API knowledge.

initialize

public void initialize()
                throws IOException

Forces initialization of this index (actual parsing of index pages). normally, the index will not be initialized until the entries are actually needed.

Throws:

IOException

update

public void update()
            throws IOException

Writes the current index state to the database.

Forces index initialization.

Throws:

IOException

read

public void read(ByteBuffer tableBuffer,
                 List<Column> availableColumns)
          throws IOException

Read the rest of the index info from a tableBuffer

Parameters:

tableBuffer - table definition buffer to read from initial info

availableColumns - Columns that this index may use

Throws:

IOException

addRow

public void addRow(Object[] row,
                   RowId rowId)
            throws IOException

Adds a row to this index

Forces index initialization.

Parameters:

row - Row to add

rowId - rowId of the row to be added

Throws:

IOException

deleteRow

public void deleteRow(Object[] row,
                      RowId rowId)
               throws IOException

Removes a row from this index

Forces index initialization.

Parameters:

row - Row to remove

rowId - rowId of the row to be removed

Throws:

IOException

cursor

public IndexData.EntryCursor cursor()
                             throws IOException

Gets a new cursor for this index.

Forces index initialization.

Throws:

IOException

cursor

public IndexData.EntryCursor cursor(Object[] startRow,
                                    boolean startInclusive,
                                    Object[] endRow,
                                    boolean endInclusive)
                             throws IOException

Gets a new cursor for this index, narrowed to the range defined by the given startRow and endRow.

Forces index initialization.

Parameters:

startRow - the first row of data for the cursor, or null for the first entry

startInclusive - whether or not startRow is inclusive or exclusive

endRow - the last row of data for the cursor, or null for the last entry

endInclusive - whether or not endRow is inclusive or exclusive

Throws:

IOException

constructIndexRowFromEntry

public Object[] constructIndexRowFromEntry(Object... values)

Constructs an array of values appropriate for this index from the given column values, expected to match the columns for this index.

Returns:

the appropriate sparse array of data

Throws:

IllegalArgumentException - if the wrong number of values are provided

constructIndexRow

public Object[] constructIndexRow(String colName,
                                  Object value)

Constructs an array of values appropriate for this index from the given column value.

Returns:

the appropriate sparse array of data or null if not all columns for this index were provided

constructIndexRow

public Object[] constructIndexRow(Map<String,?> row)

Constructs an array of values appropriate for this index from the given column values.

Returns:

the appropriate sparse array of data or null if not all columns for this index were provided

toString

public String toString()

Overrides:

toString in class Object