Package mondrian.rolap

Class RolapStar

java.lang.Object

mondrian.rolap.RolapStar

public class RolapStar
extends Object

A RolapStar is a star schema. It is the means to read cell values.

todo: Move this class into a package that specializes in relational aggregation, doesn't know anything about hierarchies etc.

Since:

12 August, 2001

Author:

jhyde

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	RolapStar.AliasReplacer	Creates a copy of an expression, everywhere replacing one alias with another.
static class	RolapStar.Bar	Temporary.
static class	RolapStar.Column	A column in a star schema.
static class	RolapStar.ColumnComparator	Comparator to compare columns based on their name and table that contains them
static class	RolapStar.Condition
static class	RolapStar.Measure	Definition of a measure in a star schema.
static class	RolapStar.Table	Definition of a table in a star schema.

Method Summary

Modifier and Type	Method	Description
void	addAggStar(AggStar aggStar)	Adds an AggStar to this star.
protected MondrianDef.RelationOrJoin	cloneRelation(MondrianDef.Relation rel, String possibleName)
static void	collectColumns(Collection<RolapStar.Column> columnList, RolapStar.Table table, MondrianDef.Column joinColumn)	Collects all columns in this table and its children.
String	generateSql(List<RolapStar.Column> columnList, List<String> columnNameList)	Generates a SQL statement to read all instances of the given attributes.
List<AggStar>	getAggStars()	Returns this RolapStar's aggregate table AggStars, ordered in ascending order of size.
List<String>	getAliasList()	Returns a list of all aliases used in this star.
BitKey	getBitKey(String[] tableAlias, String[] columnName)
Object	getCellFromAllCaches(CellRequest request)
Object	getCellFromCache(CellRequest request, RolapAggregationManager.PinSet pinSet)	Retrieves the value of the cell identified by a cell request, if it can be found in the local cache of the current statement (thread).
DataSourceChangeListener	getChangeListener()	Returns the listener for changes to this star's underlying database.
RolapStar.Column	getColumn(int bitPos)	Look up the column at the given bit position.
int	getColumnCount()	Returns this RolapStar's column count.
DataSource	getDataSource()	Returns the DataSource used to connect to the underlying DBMS.
RolapStar.Table	getFactTable()	Returns the fact table at the center of this RolapStar.
RolapSchema	getSchema()
SqlQuery	getSqlQuery()	Clones an existing SqlQuery to create a new one (this cloning creates one with an empty sql query).
Dialect	getSqlQueryDialect()	Returns this RolapStar's SQL dialect.
static RolapStar.Measure	getStarMeasure(Member member)	Retrieves the RolapStar.Measure in which a measure is stored.
RolapStatisticsCache	getStatisticsCache()
MondrianDef.RelationOrJoin	getUniqueRelation(MondrianDef.RelationOrJoin rel, String factForeignKey, String primaryKey, String primaryKeyTable)	Generates a unique relational join to the fact table via re-aliasing MondrianDef.Relations currently called in the RolapCubeHierarchy constructor.
RolapStar.Column	lookupColumn(String tableAlias, String columnName)	This is used by TestAggregationManager only.
RolapStar.Column[]	lookupColumns(String tableAlias, String columnName)	Retrieves a named column, returns null if not found.
Aggregation	lookupOrCreateAggregation(AggregationKey aggregationKey)	Looks up an aggregation or creates one if it does not exist in an atomic (synchronized) operation.
Aggregation	lookupSegment(AggregationKey aggregationKey)	Looks for an existing aggregation over a given set of columns, in the local segment cache, returning null if there is none.
void	prepareToLoadAggregates()	Place holder in case in the future we wish to be able to reload aggregates.
void	print(PrintWriter pw, String prefix, boolean structure)	Prints the state of this RolapStar
void	register(SegmentWithData segment)
void	reOrderAggStarList()	Reorder the list of aggregate stars.
void	setChangeListener(DataSourceChangeListener changeListener)	Sets the listener for changes to this star's underlying database.
void	setDataSource(DataSource dataSource)	For testing purposes only.
String	toString()

Methods inherited from class java.lang.Object

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

Method Detail

getCellFromCache

public Object getCellFromCache(CellRequest request,
                               RolapAggregationManager.PinSet pinSet)

Retrieves the value of the cell identified by a cell request, if it can be found in the local cache of the current statement (thread).

If it is not in the local cache, returns null. The client's next step will presumably be to request a segment that contains the cell from the global cache, external cache, or by issuing a SQL statement.

Returns Util.nullValue if a segment contains the cell and the cell's value is null.

If pinSet is not null, pins the segment that holds it into the local cache. pinSet ensures that a segment is only pinned once.

Parameters:

request - Cell request

pinSet - Set into which to pin the segment; or null

Returns:

Cell value, or Util.nullValue if the cell value is null, or null if the cell is not in any segment in the local cache.

getCellFromAllCaches

public Object getCellFromAllCaches(CellRequest request)

register

public void register(SegmentWithData segment)

getStatisticsCache

public RolapStatisticsCache getStatisticsCache()

cloneRelation

protected MondrianDef.RelationOrJoin cloneRelation(MondrianDef.Relation rel,
                                                   String possibleName)

getUniqueRelation

public MondrianDef.RelationOrJoin getUniqueRelation(MondrianDef.RelationOrJoin rel,
                                                    String factForeignKey,
                                                    String primaryKey,
                                                    String primaryKeyTable)

Generates a unique relational join to the fact table via re-aliasing MondrianDef.Relations currently called in the RolapCubeHierarchy constructor. This should eventually be phased out and replaced with RolapStar.Table and RolapStar.Column references

Parameters:

rel - the relation needing uniqueness

factForeignKey - the foreign key of the fact table

primaryKey - the join key of the relation

primaryKeyTable - the join table of the relation

Returns:

if necessary a new relation that has been re-aliased

getColumnCount

public int getColumnCount()

Returns this RolapStar's column count. After a star has been created with all of its columns, this is the number of columns in the star.

prepareToLoadAggregates

public void prepareToLoadAggregates()

Place holder in case in the future we wish to be able to reload aggregates. In that case, if aggregates had already been loaded, i.e., this star has some aggstars, then those aggstars are cleared.

addAggStar

public void addAggStar(AggStar aggStar)

Adds an AggStar to this star.

Internally the AggStars are added in sort order, smallest row count to biggest, so that the most efficient AggStar is encountered first; ties do not matter.

reOrderAggStarList

public void reOrderAggStarList()

Reorder the list of aggregate stars. This should be called if the algorithm used to order the AggStars has been changed.

getAggStars

public List<AggStar> getAggStars()

Returns this RolapStar's aggregate table AggStars, ordered in ascending order of size.

getFactTable

public RolapStar.Table getFactTable()

Returns the fact table at the center of this RolapStar.

Returns:

fact table

getSqlQuery

public SqlQuery getSqlQuery()

Clones an existing SqlQuery to create a new one (this cloning creates one with an empty sql query).

getSqlQueryDialect

public Dialect getSqlQueryDialect()

Returns this RolapStar's SQL dialect.

lookupOrCreateAggregation

public Aggregation lookupOrCreateAggregation(AggregationKey aggregationKey)

Looks up an aggregation or creates one if it does not exist in an atomic (synchronized) operation.

When a new aggregation is created, it is marked as thread local.

Parameters:

aggregationKey - this is the constrained column bitkey

lookupSegment

public Aggregation lookupSegment(AggregationKey aggregationKey)

Looks for an existing aggregation over a given set of columns, in the local segment cache, returning null if there is none.

Must be called from synchronized context.

See Also:

currently always returns null -- remove

setDataSource

public void setDataSource(DataSource dataSource)

For testing purposes only.

getDataSource

public DataSource getDataSource()

Returns the DataSource used to connect to the underlying DBMS.

Returns:

DataSource

getStarMeasure

public static RolapStar.Measure getStarMeasure(Member member)

Retrieves the RolapStar.Measure in which a measure is stored.

lookupColumns

public RolapStar.Column[] lookupColumns(String tableAlias,
                                        String columnName)

Retrieves a named column, returns null if not found.

lookupColumn

public RolapStar.Column lookupColumn(String tableAlias,
                                     String columnName)

This is used by TestAggregationManager only.

getBitKey

public BitKey getBitKey(String[] tableAlias,
                        String[] columnName)

getAliasList

public List<String> getAliasList()

Returns a list of all aliases used in this star.

collectColumns

public static void collectColumns(Collection<RolapStar.Column> columnList,
                                  RolapStar.Table table,
                                  MondrianDef.Column joinColumn)

Collects all columns in this table and its children. If joinColumn is specified, only considers child tables joined by the given column.

getColumn

public RolapStar.Column getColumn(int bitPos)

Look up the column at the given bit position.

Parameters:

bitPos - bit position to look up

Returns:

column at the given position

getSchema

public RolapSchema getSchema()

generateSql

public String generateSql(List<RolapStar.Column> columnList,
                          List<String> columnNameList)

Generates a SQL statement to read all instances of the given attributes.

The SQL statement is of the form SELECT ... FROM ... JOIN ... GROUP BY .... It is useful for populating an aggregate table.

Parameters:

columnList - List of columns (attributes and measures)

columnNameList - List of column names (must have same cardinality as columnList)

Returns:

SQL SELECT statement

toString

public String toString()

Overrides:

toString in class Object

print

public void print(PrintWriter pw,
                  String prefix,
                  boolean structure)

Prints the state of this RolapStar

Parameters:

pw - Writer

prefix - Prefix to print at the start of each line

structure - Whether to print the structure of the star

getChangeListener

public DataSourceChangeListener getChangeListener()

Returns the listener for changes to this star's underlying database.

Returns:

Returns the Data source change listener.

setChangeListener

public void setChangeListener(DataSourceChangeListener changeListener)

Sets the listener for changes to this star's underlying database.

Parameters:

changeListener - The Data source change listener to set