com.healthmarketscience.jackcess.impl
Class IndexData

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

public 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
static class	IndexData.PendingChange Utility class which maintains information about a pending index update.

Field Summary

static byte	ASCENDING_COLUMN_FLAG
static Comparator<byte[]>	BYTE_CODE_COMPARATOR
static IndexData.Entry	FIRST_ENTRY special entry which is less than any other entry
static byte	IGNORE_NULLS_INDEX_FLAG
static IndexData.Entry	LAST_ENTRY special entry which is greater than any other entry
static int	MAX_COLUMNS Max number of columns in an index
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
static byte	SPECIAL_INDEX_FLAG
static byte	UNIQUE_INDEX_FLAG
static byte	UNKNOWN_INDEX_FLAG

Method Summary

static void	commitAll(IndexData.PendingChange change)
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(TableImpl 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, RowIdImpl rowId) Removes a row from this index
List<IndexData.ColumnDescriptor>	getColumns() Returns the Columns for this index (unmodifiable)
int	getEntryCount() Returns the number of index entries in the index.
JetFormat	getFormat()
int	getIndexDataNumber()
List<Index>	getIndexes()
byte	getIndexFlags()
String	getName()
int	getOwnedPageCount() Returns the number of database pages owned by this index data.
PageChannel	getPageChannel()
Index	getPrimaryIndex()
TableImpl	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.
IndexData.PendingChange	prepareAddRow(Object[] row, RowIdImpl rowId, IndexData.PendingChange nextChange) Prepares to add a row to this index.
IndexData.PendingChange	prepareUpdateRow(Object[] oldRow, RowIdImpl rowId, Object[] newRow, IndexData.PendingChange nextChange) Prepares to update a row in this index.
void	read(ByteBuffer tableBuffer, List<ColumnImpl> availableColumns) Read the rest of the index info from a tableBuffer
static void	rollbackAll(IndexData.PendingChange change)
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.
void	validate() Used by unit tests to validate the internal status of the index.

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

MAX_COLUMNS

public static final int MAX_COLUMNS

Max number of columns in an index

See Also:

Constant Field Values

ASCENDING_COLUMN_FLAG

public static final byte ASCENDING_COLUMN_FLAG

See Also:

Constant Field Values

UNIQUE_INDEX_FLAG

public static final byte UNIQUE_INDEX_FLAG

See Also:

Constant Field Values

IGNORE_NULLS_INDEX_FLAG

public static final byte IGNORE_NULLS_INDEX_FLAG

See Also:

Constant Field Values

SPECIAL_INDEX_FLAG

public static final byte SPECIAL_INDEX_FLAG

See Also:

Constant Field Values

UNKNOWN_INDEX_FLAG

public static final byte UNKNOWN_INDEX_FLAG

See Also:

Constant Field Values

BYTE_CODE_COMPARATOR

public static final Comparator<byte[]> BYTE_CODE_COMPARATOR

Method Detail

create

public static IndexData create(TableImpl 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

getName

public String getName()

getTable

public TableImpl 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.

validate

public void validate()
              throws IOException

Used by unit tests to validate the internal status of the index.

Throws:

IOException

Usage:

Advanced: This method is for advanced/internal use.

getEntryCount

public int getEntryCount()
                  throws IOException

Returns the number of index entries in the index. Only called by unit tests.

Forces index initialization.

Throws:

IOException

Usage:

Advanced: This method is for advanced/internal use.

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<ColumnImpl> 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

prepareAddRow

public IndexData.PendingChange prepareAddRow(Object[] row,
                                             RowIdImpl rowId,
                                             IndexData.PendingChange nextChange)
                                      throws IOException

Prepares to add a row to this index. All constraints are checked before this method returns.

Forces index initialization.

Parameters:

row - Row to add

rowId - rowId of the row to be added

Returns:

a PendingChange which can complete the addition or roll it back

Throws:

IOException

prepareUpdateRow

public IndexData.PendingChange prepareUpdateRow(Object[] oldRow,
                                                RowIdImpl rowId,
                                                Object[] newRow,
                                                IndexData.PendingChange nextChange)
                                         throws IOException

Prepares to update a row in this index. All constraints are checked before this method returns.

Forces index initialization.

Parameters:

oldRow - Row to be removed

newRow - Row to be added

rowId - rowId of the row to be updated

Returns:

a PendingChange which can complete the update or roll it back

Throws:

IOException

deleteRow

public void deleteRow(Object[] row,
                      RowIdImpl 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

commitAll

public static void commitAll(IndexData.PendingChange change)
                      throws IOException

Throws:

IOException

rollbackAll

public static void rollbackAll(IndexData.PendingChange change)
                        throws IOException

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