com.healthmarketscience.jackcess
Class Index

java.lang.Object
  com.healthmarketscience.jackcess.Index

All Implemented Interfaces:

Comparable<Index>

Direct Known Subclasses:

BigIndex, SimpleIndex

public abstract class Index
extends Object
implements Comparable<Index>

Access table index

Author:

Tim McCune

Nested Class Summary

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

Field Summary

static Index.Entry	FIRST_ENTRY special entry which is less than any other entry
static Index.Entry	LAST_ENTRY special entry which is greater than any other entry

Method Summary

void	addRow(Object[] row, RowId rowId) Adds a row to this index
int	compareTo(Index other)
Object[]	constructIndexRow(Map<String,Object> 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.
Index.EntryCursor	cursor() Gets a new cursor for this index.
Index.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<Index.ColumnDescriptor>	getColumns() Returns the Columns for this index (unmodifiable)
JetFormat	getFormat()
byte	getIndexFlags()
int	getIndexNumber()
String	getName()
PageChannel	getPageChannel()
Table	getTable()
int	getUniqueEntryCount()
int	getUniqueEntryCountOffset()
void	initialize() Forces initialization of this index (actual parsing of index pages).
boolean	isForeignKey()
boolean	isInitialized() Whether or not the complete index state has been read.
boolean	isPrimaryKey()
boolean	isUnique() Whether or not index entries must be unique.
void	read(ByteBuffer tableBuffer, List<Column> availableColumns) Read the index info from a tableBuffer
void	setIndexNumber(int indexNumber)
void	setIndexType(byte indexType)
void	setName(String name)
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 Index.Entry FIRST_ENTRY

special entry which is less than any other entry

LAST_ENTRY

public static final Index.Entry LAST_ENTRY

special entry which is greater than any other entry

Method Detail

getTable

public Table getTable()

getFormat

public JetFormat getFormat()

getPageChannel

public PageChannel getPageChannel()

setIndexNumber

public void setIndexNumber(int indexNumber)

getIndexNumber

public int getIndexNumber()

setIndexType

public void setIndexType(byte indexType)

getIndexFlags

public byte getIndexFlags()

getUniqueEntryCount

public int getUniqueEntryCount()

getUniqueEntryCountOffset

public int getUniqueEntryCountOffset()

getName

public String getName()

setName

public void setName(String name)

isPrimaryKey

public boolean isPrimaryKey()

isForeignKey

public boolean isForeignKey()

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<Index.ColumnDescriptor> getColumns()

Returns the Columns for this index (unmodifiable)

isInitialized

public boolean isInitialized()

Whether or not the complete index state has been read.

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 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 Index.EntryCursor cursor()
                         throws IOException

Gets a new cursor for this index.

Forces index initialization.

Throws:

IOException

cursor

public Index.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,Object> 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

compareTo

public int compareTo(Index other)

Specified by:

compareTo in interface Comparable<Index>