ca.sqlpower.wabit.rs.olap
Class OlapQuery

java.lang.Object
  ca.sqlpower.object.AbstractSPObject
      ca.sqlpower.wabit.AbstractWabitObject
          ca.sqlpower.wabit.rs.olap.OlapQuery

All Implemented Interfaces:

ca.sqlpower.object.SPObject, ResultSetProducer, WabitBackgroundWorker, WabitObject

@ThreadSafe
public class OlapQuery
extends AbstractWabitObject
implements ResultSetProducer

This is the model of an OLAP query. This will store all values that need to be persisted in an OLAP query.

Instances of OlapQuery are thread safe: their state can me modified safely by multiple threads. To avoid thrashing the remote database, execution of the query is serialized so that only one MDX query evaluation at a time is in progress. However, while the query is executing, threads attempting to further modify the query's state are not blocked as long as they don't involve an attempt to execute the query.

Sometimes, you might want to perform a series of operations (such as adding or removing many members) atomically. You can do so by synchronizing on the OlapQuery instance, like this:

  OlapQuery query = ...;
  synchronized (query) {
    for (Member member : membersToInclude) {
      query.includeMember(member);
    }
  }
 

This will guarantee all the members in the list have been added to the query with no intervening modifications to the query and no possibility that the query would start executing on another thread when only half the members have been added.

Field Summary

Fields inherited from class ca.sqlpower.object.AbstractSPObject

uuid

Constructor Summary

OlapQuery(OlapConnectionMapping olapMapping)
Creates a new, empty query with no set persistent object ID.

OlapQuery(java.lang.String uuid, OlapConnectionMapping olapMapping, java.lang.String name, java.lang.String queryName, java.lang.String catalogName, java.lang.String schemaName, java.lang.String cubeName)
Creates a new, empty query that will use the given persistent object ID when it's saved.

Method Summary

void	addAxis(WabitOlapAxis axis) Adds the given axis to the query.
protected void	addChildImpl(ca.sqlpower.object.SPObject child, int index) This method should only be used internally or in special cases such as an undo manager or synchronizing with a server.
void	addOlapQueryListener(OlapQueryListener listener)
void	addResultSetListener(ResultSetListener listener) Adds the given listener to this result set producer's list of interested parties.
void	addToAxis(int ordinal, org.olap4j.metadata.Member member, org.olap4j.Axis axis) Adds the given member to the given axis.
void	addToAxis(int ordinal, org.olap4j.metadata.Member member, org.olap4j.query.Selection.Operator operator, org.olap4j.Axis axis) Adds the given member to the given axis with a defined operator.
boolean	allowsChildren() OlapQuery has WabitOlapAxis as children, so this method returns true.
void	cancel() If this worker is currently doing something in the background, calling this method requests the background processing be canceled.
int	childPositionOffset(java.lang.Class<? extends ca.sqlpower.object.SPObject> childType)
void	clearExclusions(org.olap4j.metadata.Hierarchy hierarchy) Takes the given Hierarchy and clears all exclusions from its Dimension.
void	clearSort(org.olap4j.Axis axis) Removes the sort order on the given axis
static OlapQuery	copyOlapQuery(OlapQuery oldOlapQuery) Creates a copy of the given OlapQuery.
org.olap4j.OlapConnection	createOlapConnection()
void	drillReplace(org.olap4j.metadata.Member member) Modifies this query's selection so that members equal to and descended from the given member remain selected as before, but other members are no longer selected.
void	drillUpTo(org.olap4j.metadata.Member fromMember, org.olap4j.metadata.Member targetAncestor) Modifies this query's selection so that targetAncestor, and every ancestor of fromMember in between will be included.
void	excludeMember(java.lang.String dimensionName, org.olap4j.metadata.Member memberToExclude, org.olap4j.query.Selection.Operator operator) Adds the given Member or it's children (depending on the Selection.Operator) as an exclusion to this query.
java.util.concurrent.Future<ResultSetAndUpdateCountCollection>	execute() Executes the underlying MDX query, causing all the side effects described in executeOlapQuery(), then converts those results to an OlapResultSet and notifies the ResultSetListeners with that converted result.
org.olap4j.CellSet	executeOlapQuery() Executes the current MDX query represented by this object, returning the cell set that results from the query's execution.
org.olap4j.metadata.Member	findMember(java.util.Map<java.lang.String,java.lang.String> attributes, org.olap4j.metadata.Cube cube) This method finds a member from a cube based on given attributes.
java.util.List<java.lang.Class<? extends ca.sqlpower.object.SPObject>>	getAllowedChildTypes()
java.util.List<WabitOlapAxis>	getAxes() Returns the list of Axis wrappers stored by this query.
java.lang.String	getCatalogName()
java.util.List<? extends WabitObject>	getChildren()
java.util.List<org.olap4j.metadata.Hierarchy>	getColumnHierarchies()
java.lang.String	getCubeName()
org.olap4j.metadata.Cube	getCurrentCube()
java.util.List<WabitObject>	getDependencies()
WabitOlapDimension	getDimension(java.lang.String dimensionName) Gets the wrapper around the Dimension with the given name.
java.lang.String	getMdxText() Returns the current MDX text that this query object's state represents.
ca.sqlpower.sql.Olap4jDataSource	getOlapDataSource() Returns the data source that this query obtains its connections from.
java.lang.String	getQueryName()
java.util.List<org.olap4j.metadata.Hierarchy>	getRowHierarchies()
java.lang.String	getSchemaName()
org.olap4j.metadata.Member	getSlicerMember() This method returns the single slicer member, since Olap4j does not track whether or not you have more than one member in your slicer and since mondrian does not support compound slicers we will use this variable to make sure that the user does not add more than one member to their slicer
org.olap4j.query.SortOrder	getSortOrder(org.olap4j.Axis axis) Returns the SortOrder of the given Axis of the query.
boolean	hasCachedAttributes() Tells if the connection was initialized.
void	includeMember(org.olap4j.metadata.Member member) Includes the given member in the query, assuming its hierarchy is on a visible axis.
boolean	isIncluded(org.olap4j.metadata.Member member) Checks if the given Member is already included in the given QueryDimension.
boolean	isInitDone() This method lets you know whether or not the OlapQuery has been initialized.
boolean	isNonEmpty() Tells whether the ROWS axis of this query omits empty positions.
boolean	isRunning() Returns true if this Wabit object is doing something in the background.
protected boolean	removeChildImpl(ca.sqlpower.object.SPObject child) This method should only be used internally or in special cases such as an undo manager or synchronizing with a server.
void	removeDependency(ca.sqlpower.object.SPObject dependency)
void	removeDimension(org.olap4j.metadata.Dimension dimension, org.olap4j.Axis axis) Removes the given Dimension from the given Axis in the query
boolean	removeExcludedMember(org.olap4j.metadata.Member memberToExclude, org.olap4j.query.Selection.Operator operator) Removes the given member with the given operator from the list of members that are currently being excluded from the query.
void	removeHierarchy(org.olap4j.metadata.Hierarchy hierarchy, org.olap4j.Axis axis) Removes the given Hierarchy from the given Axis in the query
boolean	removeIncludedMember(org.olap4j.metadata.Member member, org.olap4j.query.Selection.Operator operator) Removes the given member from the list of members included in this query.
void	removeOlapQueryListener(OlapQueryListener listener)
void	removeResultSetListener(ResultSetListener listener) Removes the given listener from the listener list.
void	reset() This function is called by the 'Reset Query' button on the toolbar.
void	setCurrentCube(org.olap4j.metadata.Cube currentCube)
void	setCurrentCube(org.olap4j.metadata.Cube currentCube, boolean resetQuery)
void	setNonEmpty(boolean nonEmpty) Sets the ROWS axis of this query to omit empty positions.
void	setOlapDataSource(ca.sqlpower.sql.Olap4jDataSource olapDataSource) Sets the data source that this query obtains its connections from, and fires a property change event.
void	sortBy(org.olap4j.Axis axis, org.olap4j.query.SortOrder order, org.olap4j.metadata.Measure measure) Sorts the OLAP results on the given Axis by the given Measure in the given SortOrder
boolean	toggleMember(org.olap4j.metadata.Member member) If the member is currently "expanded" (its children are part of the MDX query), its children will be removed from the query.
java.lang.String	toString() Returns the name of the string.
void	updateAttributes() Updates the child references on all Olap wrapper classes owned by this query.

Methods inherited from class ca.sqlpower.wabit.AbstractWabitObject

cleanup, commit, equals, generateNewUUID, getParent, getSession, isForegroundThread, removeChild, rollback, runInBackground, runInForeground

Methods inherited from class ca.sqlpower.object.AbstractSPObject

addChild, addSPListener, begin, fireChildAdded, fireChildRemoved, firePropertyChange, firePropertyChange, firePropertyChange, fireTransactionEnded, fireTransactionRollback, fireTransactionStarted, getChildren, getName, getUUID, removeSPListener, setName, setParent, setUUID

Methods inherited from class java.lang.Object

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

Methods inherited from interface ca.sqlpower.wabit.WabitObject

getParent

Methods inherited from interface ca.sqlpower.object.SPObject

addChild, addSPListener, begin, cleanup, commit, generateNewUUID, getChildren, getName, getSession, getUUID, removeChild, removeSPListener, rollback, setName, setParent, setUUID

Constructor Detail

OlapQuery

public OlapQuery(OlapConnectionMapping olapMapping)

Creates a new, empty query with no set persistent object ID.

OlapQuery

public OlapQuery(java.lang.String uuid,
                 OlapConnectionMapping olapMapping,
                 java.lang.String name,
                 java.lang.String queryName,
                 java.lang.String catalogName,
                 java.lang.String schemaName,
                 java.lang.String cubeName)

Creates a new, empty query that will use the given persistent object ID when it's saved. This constructor is only of particular use to the persistence layer.

Method Detail

copyOlapQuery

public static OlapQuery copyOlapQuery(OlapQuery oldOlapQuery)
                               throws java.sql.SQLException,
                                      QueryInitializationException

Creates a copy of the given OlapQuery.

Throws:

java.sql.SQLException

QueryInitializationException

setCurrentCube

public void setCurrentCube(org.olap4j.metadata.Cube currentCube)
                    throws java.sql.SQLException

Throws:

java.sql.SQLException

setCurrentCube

public void setCurrentCube(org.olap4j.metadata.Cube currentCube,
                           boolean resetQuery)
                    throws java.sql.SQLException

Throws:

java.sql.SQLException

getCurrentCube

public org.olap4j.metadata.Cube getCurrentCube()

executeOlapQuery

public org.olap4j.CellSet executeOlapQuery()
                                    throws QueryInitializationException,
                                           java.lang.InterruptedException,
                                           java.sql.SQLException

Executes the current MDX query represented by this object, returning the cell set that results from the query's execution.

Every call to this method results in a CellSetEvent and a ResultSetProducerEvent being fired.

Throws:

java.sql.SQLException - If the cell set cannot be iterated over or its values cannot be retrieved to create a result set based off of the cell set.

QueryInitializationException

java.lang.InterruptedException

See Also:

innerExecuteOlapQuery()

removeHierarchy

public void removeHierarchy(org.olap4j.metadata.Hierarchy hierarchy,
                            org.olap4j.Axis axis)
                     throws QueryInitializationException

Removes the given Hierarchy from the given Axis in the query

Parameters:

hierarchy - The Hierarchy to remove

axis - The Axis to remove the Hierarchy from

Throws:

QueryInitializationException

removeDimension

public void removeDimension(org.olap4j.metadata.Dimension dimension,
                            org.olap4j.Axis axis)
                     throws QueryInitializationException

Removes the given Dimension from the given Axis in the query

Parameters:

dimension - The Dimension to remove

axis - The Axis to remove the Dimension from

Throws:

QueryInitializationException

isInitDone

public boolean isInitDone()

This method lets you know whether or not the OlapQuery has been initialized.

Returns:

The boolean value that is responsible for tracking whether or not the OlapQuery has been initialized.

reset

public void reset()
           throws java.sql.SQLException

This function is called by the 'Reset Query' button on the toolbar. It will replace the current MDX Query with a blank one.

Throws:

java.sql.SQLException

excludeMember

public void excludeMember(java.lang.String dimensionName,
                          org.olap4j.metadata.Member memberToExclude,
                          org.olap4j.query.Selection.Operator operator)
                   throws QueryInitializationException

Adds the given Member or it's children (depending on the Selection.Operator) as an exclusion to this query.

Parameters:

dimensionName - The name of the Dimension to exclude Member from.

memberToExclude - The Member to exclude from the query results

operator - If value is Selection.Operator.MEMBER, the given Member is excluded. If the value is Selection.Operator.CHILDREN, then the Member's children get excluded. Due to insufficient documentation in the Olap4j API, I am not certain what the other values of Selection.Operator will do.

Throws:

QueryInitializationException

removeExcludedMember

public boolean removeExcludedMember(org.olap4j.metadata.Member memberToExclude,
                                    org.olap4j.query.Selection.Operator operator)
                             throws QueryInitializationException

Removes the given member with the given operator from the list of members that are currently being excluded from the query.

Parameters:

memberToExclude - The member that was excluded that we now want to remove from the list of exclusions.

operator - The operator that the member is being excluded with.

Returns:

True if the member was successfully removed from the list of exclusions, false otherwise.

Throws:

QueryInitializationException

createOlapConnection

public org.olap4j.OlapConnection createOlapConnection()
                                               throws java.sql.SQLException,
                                                      java.lang.ClassNotFoundException,
                                                      javax.naming.NamingException

Throws:

java.sql.SQLException

java.lang.ClassNotFoundException

javax.naming.NamingException

setOlapDataSource

public void setOlapDataSource(ca.sqlpower.sql.Olap4jDataSource olapDataSource)

Sets the data source that this query obtains its connections from, and fires a property change event.

getOlapDataSource

public ca.sqlpower.sql.Olap4jDataSource getOlapDataSource()

Returns the data source that this query obtains its connections from.

getSlicerMember

public org.olap4j.metadata.Member getSlicerMember()

This method returns the single slicer member, since Olap4j does not track whether or not you have more than one member in your slicer and since mondrian does not support compound slicers we will use this variable to make sure that the user does not add more than one member to their slicer

allowsChildren

public boolean allowsChildren()

OlapQuery has WabitOlapAxis as children, so this method returns true.

Specified by:

allowsChildren in interface ca.sqlpower.object.SPObject

childPositionOffset

public int childPositionOffset(java.lang.Class<? extends ca.sqlpower.object.SPObject> childType)

Specified by:

childPositionOffset in interface ca.sqlpower.object.SPObject

getChildren

public java.util.List<? extends WabitObject> getChildren()

Specified by:

getChildren in interface ca.sqlpower.object.SPObject

toString

public java.lang.String toString()

Returns the name of the string. This way reasonable text appears when these queries are placed in a combo box.

Overrides:

toString in class AbstractWabitObject

getDependencies

public java.util.List<WabitObject> getDependencies()

Specified by:

getDependencies in interface ca.sqlpower.object.SPObject

removeDependency

public void removeDependency(ca.sqlpower.object.SPObject dependency)

Specified by:

removeDependency in interface ca.sqlpower.object.SPObject

updateAttributes

public void updateAttributes()

Updates the child references on all Olap wrapper classes owned by this query. Also fires events for all additions and removals since the last call.

addAxis

public void addAxis(WabitOlapAxis axis)

Adds the given axis to the query. Adding an axis this way will define the query to be loaded as a side effect.

getAxes

public java.util.List<WabitOlapAxis> getAxes()

Returns the list of Axis wrappers stored by this query.

getDimension

public WabitOlapDimension getDimension(java.lang.String dimensionName)

Gets the wrapper around the Dimension with the given name.

findMember

public org.olap4j.metadata.Member findMember(java.util.Map<java.lang.String,java.lang.String> attributes,
                                             org.olap4j.metadata.Cube cube)

This method finds a member from a cube based on given attributes.

toggleMember

public boolean toggleMember(org.olap4j.metadata.Member member)
                     throws QueryInitializationException

If the member is currently "expanded" (its children are part of the MDX query), its children will be removed from the query. Otherwise (the member's children are not showing), the member's children will be added to the query. In either case, the query will be re-executed after the member selections have been adjusted.

Parameters:

member - The member whose drilldown state to toggle. Must not be null.

Returns:

Returns true if the query was NOT expanded

Throws:

QueryInitializationException

org.olap4j.OlapException - if the list of child members can't be retrieved

hasCachedAttributes

public boolean hasCachedAttributes()

Tells if the connection was initialized.

getSortOrder

public org.olap4j.query.SortOrder getSortOrder(org.olap4j.Axis axis)
                                        throws QueryInitializationException

Returns the SortOrder of the given Axis of the query.

Parameters:

axis - The Axis for which you want to find the SortOrder for

Returns:

The current SortOrder of the given Axis

Throws:

QueryInitializationException - If there is an error initializing the query

getMdxText

public java.lang.String getMdxText()
                            throws QueryInitializationException

Returns the current MDX text that this query object's state represents.

Throws:

QueryInitializationException

addToAxis

public void addToAxis(int ordinal,
                      org.olap4j.metadata.Member member,
                      org.olap4j.Axis axis)
               throws org.olap4j.OlapException,
                      QueryInitializationException

Adds the given member to the given axis.

Parameters:

ordinal - If the given member's dimension is not already on the given axis, the dimension will be added to the axis at the given ordinal. Otherwise, this argument is ignored.

member - The member to add. If the member's dimension is not already on the given axis, it will be added to the axis automatically.

axis - The axis to add the member to. Must be either Axis.ROWS or Axis.COLUMNS.

Throws:

org.olap4j.OlapException - If a database error occurs

QueryInitializationException

addToAxis

public void addToAxis(int ordinal,
                      org.olap4j.metadata.Member member,
                      org.olap4j.query.Selection.Operator operator,
                      org.olap4j.Axis axis)
               throws org.olap4j.OlapException,
                      QueryInitializationException

Adds the given member to the given axis with a defined operator.

Parameters:

ordinal - If the given member's dimension is not already on the given axis, the dimension will be added to the axis at the given ordinal. Otherwise, this argument is ignored.

member - The member to add. If the member's dimension is not already on the given axis, it will be added to the axis automatically.

operator - The operator to add with the member to the axis.

axis - The axis to add the member to. Must be either Axis.ROWS or Axis.COLUMNS.

Throws:

org.olap4j.OlapException - If a database error occurs

QueryInitializationException

getRowHierarchies

public java.util.List<org.olap4j.metadata.Hierarchy> getRowHierarchies()
                                                                throws QueryInitializationException

Throws:

QueryInitializationException

getColumnHierarchies

public java.util.List<org.olap4j.metadata.Hierarchy> getColumnHierarchies()
                                                                   throws QueryInitializationException

Throws:

QueryInitializationException

drillReplace

public void drillReplace(org.olap4j.metadata.Member member)
                  throws QueryInitializationException

Modifies this query's selection so that members equal to and descended from the given member remain selected as before, but other members are no longer selected.

Parameters:

member - The member to drill replace on. This member will be the new root of the selection for its hierarchy.

Throws:

QueryInitializationException

drillUpTo

public void drillUpTo(org.olap4j.metadata.Member fromMember,
                      org.olap4j.metadata.Member targetAncestor)
               throws QueryInitializationException

Modifies this query's selection so that targetAncestor, and every ancestor of fromMember in between will be included. If targetAncestor isn't actually an ancestor, it returns right away.

Parameters:

fromMember - The member whose ancestors will be added to the query selection

targetAncestor - The highest ancestor member that will be added to the query selection

Throws:

QueryInitializationException

sortBy

public void sortBy(org.olap4j.Axis axis,
                   org.olap4j.query.SortOrder order,
                   org.olap4j.metadata.Measure measure)
            throws QueryInitializationException

Sorts the OLAP results on the given Axis by the given Measure in the given SortOrder

Throws:

QueryInitializationException

clearSort

public void clearSort(org.olap4j.Axis axis)
               throws QueryInitializationException

Removes the sort order on the given axis

Parameters:

axis - The Axis from which to remove the sort order

Throws:

QueryInitializationException

isIncluded

public boolean isIncluded(org.olap4j.metadata.Member member)
                   throws QueryInitializationException

Checks if the given Member is already included in the given QueryDimension. Note that this currently does not take into account the value of Selection.getOperator()

Parameters:

member - The member to check if it's included in the given QueryDimension

dimension - The QueryDimension to check for inclusion.

Returns:

True if member is in one of the Selections in dimension's inclusions. Otherwise false.

Throws:

QueryInitializationException

includeMember

public void includeMember(org.olap4j.metadata.Member member)
                   throws QueryInitializationException

Includes the given member in the query, assuming its hierarchy is on a visible axis.

Parameters:

member - The member to include in the query. If the member is already included, this method has no effect.

Throws:

QueryInitializationException

removeIncludedMember

public boolean removeIncludedMember(org.olap4j.metadata.Member member,
                                    org.olap4j.query.Selection.Operator operator)
                             throws QueryInitializationException

Removes the given member from the list of members included in this query.

Parameters:

member - The member to remove.

operator - The operator used in the inclusion.

Returns:

True if the member was successfully removed, false otherwise.

Throws:

QueryInitializationException

setNonEmpty

public void setNonEmpty(boolean nonEmpty)

Sets the ROWS axis of this query to omit empty positions.

Parameters:

nonEmpty - True means to omit empty positions; false means to include them.

isNonEmpty

public boolean isNonEmpty()

Tells whether the ROWS axis of this query omits empty positions.

Returns:

True is this query omits empty rows; false if it includes them.

addOlapQueryListener

public void addOlapQueryListener(OlapQueryListener listener)

removeOlapQueryListener

public void removeOlapQueryListener(OlapQueryListener listener)

clearExclusions

public void clearExclusions(org.olap4j.metadata.Hierarchy hierarchy)
                     throws QueryInitializationException

Takes the given Hierarchy and clears all exclusions from its Dimension.

Parameters:

hierarchy -

Throws:

QueryInitializationException

removeChildImpl

protected boolean removeChildImpl(ca.sqlpower.object.SPObject child)

This method should only be used internally or in special cases such as an undo manager or synchronizing with a server. Removing a child of the query will only remove the Wabit wrapper around the axis of the query object.

Specified by:

removeChildImpl in class ca.sqlpower.object.AbstractSPObject

addChildImpl

protected void addChildImpl(ca.sqlpower.object.SPObject child,
                            int index)

This method should only be used internally or in special cases such as an undo manager or synchronizing with a server. Adding a child to the query will only add a Wabit wrapper for an axis of the query.

Overrides:

addChildImpl in class ca.sqlpower.object.AbstractSPObject

getQueryName

public java.lang.String getQueryName()

getCatalogName

public java.lang.String getCatalogName()

getSchemaName

public java.lang.String getSchemaName()

getCubeName

public java.lang.String getCubeName()

cancel

public void cancel()

Description copied from interface: WabitBackgroundWorker

If this worker is currently doing something in the background, calling this method requests the background processing be canceled. It is not guaranteed that cancellation will happen immediately or at all, because the background processing might involve something like database I/O with a JDBC driver that doesn't properly support cancellation.

Specified by:

cancel in interface WabitBackgroundWorker

isRunning

public boolean isRunning()

Description copied from interface: WabitBackgroundWorker

Returns true if this Wabit object is doing something in the background.

Note to implementers: this method is likely to be used for inter-thread communication. Be sure to use proper synchronization when passing the flag between threads!

Specified by:

isRunning in interface WabitBackgroundWorker

addResultSetListener

public void addResultSetListener(ResultSetListener listener)

Description copied from interface: ResultSetProducer

Adds the given listener to this result set producer's list of interested parties. Each listener on the list receives an event whenever a new result set is available (as a result of the query be executed).

Specified by:

addResultSetListener in interface ResultSetProducer

Parameters:

listener - The listener to add (must not be null).

removeResultSetListener

public void removeResultSetListener(ResultSetListener listener)

Description copied from interface: ResultSetProducer

Removes the given listener from the listener list. Has no effect if the given listener was not already on the list.

Specified by:

removeResultSetListener in interface ResultSetProducer

Parameters:

listener - The listener to remove. Nulls are ignored.

execute

public java.util.concurrent.Future<ResultSetAndUpdateCountCollection> execute()
                                                                       throws ResultSetProducerException,
                                                                              java.lang.InterruptedException

Executes the underlying MDX query, causing all the side effects described in executeOlapQuery(), then converts those results to an OlapResultSet and notifies the ResultSetListeners with that converted result.

Specified by:

execute in interface ResultSetProducer

Returns:

The results of executing of the query. If the query is not currently in a state where it can be executed, this method returns null and fires a ResultSetEvent with a null result set.

Throws:

ResultSetProducerException - If there was any problem obtaining the result set

java.lang.InterruptedException - If the calling thread is interrupted while blocked waiting for another call to execute() to complete.

getAllowedChildTypes

public java.util.List<java.lang.Class<? extends ca.sqlpower.object.SPObject>> getAllowedChildTypes()