Package com.healthmarketscience.jackcess.util

Class Joiner

java.lang.Object

com.healthmarketscience.jackcess.util.Joiner

public class Joiner
extends Object

Utility for finding rows based on pre-defined, foreign-key table relationships.

Author:

James Ahlborn

Usage:

General: This class is general use.

Method Summary

Modifier and Type	Method	Description
static Joiner	create(Index fromIndex)	Creates a new Joiner based on the given index which backs a foreign-key relationship.
static Joiner	create(Table fromTable, Table toTable)	Creates a new Joiner based on the foreign-key relationship between the given "from"" table and the given "to"" table.
Joiner	createReverse()	Creates a new Joiner that is the reverse of this Joiner (the "from" and "to" tables are swapped).
boolean	deleteRows(Object[] fromRow)	Deletes any rows in the "to" table based on the given columns in the "from" table.
boolean	deleteRows(Map<String,?> fromRow)	Deletes any rows in the "to" table based on the given columns in the "from" table.
Row	findFirstRow(Map<String,?> fromRow)	Returns the first row in the "to" table based on the given columns in the "from" table if any, null if there is no matching row.
Row	findFirstRow(Map<String,?> fromRow, Collection<String> columnNames)	Returns selected columns from the first row in the "to" table based on the given columns in the "from" table if any, null if there is no matching row.
EntryIterableBuilder	findRows(Object[] fromRow)	Returns an Iterator with the selected columns over all the rows in the "to" table based on the given columns in the "from" table.
EntryIterableBuilder	findRows(Map<String,?> fromRow)	Returns an Iterator over all the rows in the "to" table based on the given columns in the "from" table.
List<? extends Index.Column>	getColumns()
Index	getFromIndex()
Table	getFromTable()
IndexCursor	getToCursor()
Index	getToIndex()
Table	getToTable()
boolean	hasRows(Object[] fromRow)	Returns true if the "to" table has any rows based on the given columns in the "from" table, false otherwise.
boolean	hasRows(Map<String,?> fromRow)	Returns true if the "to" table has any rows based on the given columns in the "from" table, false otherwise.
String	toFKString()	Returns a pretty string describing the foreign key relationship backing this Joiner.

Methods inherited from class java.lang.Object

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

Method Detail

create

public static Joiner create(Table fromTable,
                            Table toTable)
                     throws IOException

Creates a new Joiner based on the foreign-key relationship between the given "from"" table and the given "to"" table.

Parameters:

fromTable - the "from" side of the relationship

toTable - the "to" side of the relationship

Throws:

IllegalArgumentException - if there is no relationship between the given tables

IOException

create

public static Joiner create(Index fromIndex)
                     throws IOException

Creates a new Joiner based on the given index which backs a foreign-key relationship. The table of the given index will be the "from" table and the table on the other end of the relationship will be the "to" table.

Parameters:

fromIndex - the index backing one side of a foreign-key relationship

Throws:

IOException

createReverse

public Joiner createReverse()
                     throws IOException

Creates a new Joiner that is the reverse of this Joiner (the "from" and "to" tables are swapped).

Throws:

IOException

getFromTable

public Table getFromTable()

getFromIndex

public Index getFromIndex()

getToTable

public Table getToTable()

getToIndex

public Index getToIndex()

getToCursor

public IndexCursor getToCursor()

getColumns

public List<? extends Index.Column> getColumns()

hasRows

public boolean hasRows(Map<String,?> fromRow)
                throws IOException

Returns true if the "to" table has any rows based on the given columns in the "from" table, false otherwise.

Throws:

IOException

hasRows

public boolean hasRows(Object[] fromRow)
                throws IOException

Returns true if the "to" table has any rows based on the given columns in the "from" table, false otherwise.

Throws:

IOException

Usage:

Intermediate: This method requires moderate API knowledge.

findFirstRow

public Row findFirstRow(Map<String,?> fromRow)
                 throws IOException

Returns the first row in the "to" table based on the given columns in the "from" table if any, null if there is no matching row.

Parameters:

fromRow - row from the "from" table (which must include the relevant columns for this join relationship)

Throws:

IOException

findFirstRow

public Row findFirstRow(Map<String,?> fromRow,
                        Collection<String> columnNames)
                 throws IOException

Returns selected columns from the first row in the "to" table based on the given columns in the "from" table if any, null if there is no matching row.

Parameters:

fromRow - row from the "from" table (which must include the relevant columns for this join relationship)

columnNames - desired columns in the from table row

Throws:

IOException

findRows

public EntryIterableBuilder findRows(Map<String,?> fromRow)

Returns an Iterator over all the rows in the "to" table based on the given columns in the "from" table.

Parameters:

fromRow - row from the "from" table (which must include the relevant columns for this join relationship)

findRows

public EntryIterableBuilder findRows(Object[] fromRow)

Returns an Iterator with the selected columns over all the rows in the "to" table based on the given columns in the "from" table.

Parameters:

fromRow - row from the "from" table (which must include the relevant columns for this join relationship)

deleteRows

public boolean deleteRows(Map<String,?> fromRow)

Deletes any rows in the "to" table based on the given columns in the "from" table.

Parameters:

fromRow - row from the "from" table (which must include the relevant columns for this join relationship)

Returns:

true if any "to" rows were deleted, false otherwise

deleteRows

public boolean deleteRows(Object[] fromRow)

Deletes any rows in the "to" table based on the given columns in the "from" table.

Parameters:

fromRow - row from the "from" table (which must include the relevant columns for this join relationship)

Returns:

true if any "to" rows were deleted, false otherwise

Usage:

Intermediate: This method requires moderate API knowledge.

toFKString

public String toFKString()

Returns a pretty string describing the foreign key relationship backing this Joiner.