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: put this in package which specicializes in relational aggregation, doesn't know anything about hierarchies etc.

Since:

12 August, 2001

Author:

jhyde

Nested Class Summary

static class	RolapStar.AliasReplacer Creates a copy of an expression, everywhere replacing one alias with another.
static class	RolapStar.Column A column in a star schema.
static class	RolapStar.ColumnComparator Comparator to compare columns based on their name
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.

Constructor Summary

RolapStar(RolapSchema schema, DataSource dataSource, MondrianDef.Relation fact)
Creates a RolapStar.

Method Summary

void	addAggStar(AggStar aggStar) Adds an AggStar to this star.
void	checkAggregateModifications() Checks whether an aggregation has changed since the last the time loaded.
(package private) void	clearAggStarList() Set the agg star list to empty.
(package private) void	clearCachedAggregations(boolean forced) Clears the aggregate cache.
static void	collectColumns(Collection<RolapStar.Column> columnList, RolapStar.Table table, MondrianDef.Column joinColumn) Collects all columns in this table and its children.
void	flush(CacheControl cacheControl, CacheControl.CellRegion region) Flushes the contents of a given region of cells from this star.
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)
DataSourceChangeListener	getChangeListener() Returns the listener for changes to this star's underlying database.
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).
SqlQuery.Dialect	getSqlQueryDialect() Returns this RolapStar's SQL dialect.
static RolapStar.Measure	getStarMeasure(Member member) Retrieves the RolapStar.Measure in which a measure is stored.
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.
(package private) boolean	isCacheAggregations() Returns whether the this RolapStar cache aggregates.
Aggregation	lookupAggregation(AggregationKey aggregationKey) Looks for an existing aggregation over a given set of columns, or returns null if there is none.
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.
void	prepareToLoadAggregates() This is a 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	pushAggregateModificationsToGlobalCache() Checks whether changed modifications may be pushed into global cache.
void	reOrderAggStarList() Reorder the list of aggregate stars.
(package private) void	setCacheAggregations(boolean cacheAggregations) Sets whether to cache database aggregation information; if false, cache is flushed after each query.
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

Constructor Detail

RolapStar

RolapStar(RolapSchema schema,
          DataSource dataSource,
          MondrianDef.Relation fact)

Creates a RolapStar. Please use RolapSchema.RolapStarRegistry.getOrCreateStar(mondrian.olap.MondrianDef.Relation) to create a RolapStar.

Method Detail

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()

This is a 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.

clearAggStarList

void clearAggStarList()

Set the agg star list to empty.

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 SqlQuery.Dialect getSqlQueryDialect()

Returns this RolapStar's SQL dialect.

setCacheAggregations

void setCacheAggregations(boolean cacheAggregations)

Sets whether to cache database aggregation information; if false, cache is flushed after each query.

This method is called only by the RolapCube and is only called if caching is to be turned off. Note that the same RolapStar can be associated with more than on RolapCube. If any one of those cubes has caching turned off, then caching is turned off for all of them.

Parameters:

cacheAggregations - Whether to cache database aggregation

isCacheAggregations

boolean isCacheAggregations()

Returns whether the this RolapStar cache aggregates.

See Also:

setCacheAggregations(boolean)

clearCachedAggregations

void clearCachedAggregations(boolean forced)

Clears the aggregate cache. This only does something if aggregate caching is disabled (see setCacheAggregations(boolean)).

Parameters:

forced - If true, clears cached aggregations regardless of any other settings. If false, clears only cache from the current thread

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 contrained column bitkey

lookupAggregation

public Aggregation lookupAggregation(AggregationKey aggregationKey)

Looks for an existing aggregation over a given set of columns, or returns null if there is none.

Thread local cache is taken first.

Must be called from synchronized context.

checkAggregateModifications

public void checkAggregateModifications()

Checks whether an aggregation has changed since the last the time loaded.

If so, a new thread local aggregation will be made and added after the query has finished.

This method should be called before a query is executed and afterwards the function pushAggregateModificationsToGlobalCache() should be called.

pushAggregateModificationsToGlobalCache

public void pushAggregateModificationsToGlobalCache()

Checks whether changed modifications may be pushed into global cache.

The method checks whether there are other running queries that are using the requested modifications. If this is the case, modifications are not pushed yet.

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.

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

flush

public void flush(CacheControl cacheControl,
                  CacheControl.CellRegion region)

Flushes the contents of a given region of cells from this star.

Parameters:

cacheControl - Cache control API

region - Predicate defining a region of cells

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