TSLMapQuery Class Reference

Detailed Description

Query class for data layer entities.

The TSLMapQuery object allows the user to traverse any TSLEntity instances held in memory by a data layer. A map tile consists of a single TSLEntitySet which may contain further TSLEntitySets.

A TSLMapQuery object may only be created indirectly via other API calls and should be deleted by the user using the destroy method.

A TSLStandardDataLayer component will only have one TSLEntitySet which will always be held in memory. A TSLMapDataLayer component may have a number of TSLEntitySets held in memory which may change as the view of the map changes. A TSLMapQuery component created from a TSLMapDataLayer component is only valid within the user function in which it is created. This is because the set of models held in memory may change due to modification to the TSLDrawingSurface.

Public Member Functions
void	destroy ()
const TSLEntity *	operator[] (int index) const
int	size () const

Member Function Documentation

destroy()

void TSLMapQuery::destroy

(

)

Destroy TSLMapQuery object.

This method should be called by the user as soon as the query is not required. A query should not be held open across calls to TSLDrawingSurface since any change in view may cause the map tile cache to be flushed.

operator[]()

const TSLEntity * TSLMapQuery::operator[]

(

int

index

)

const

Query a particular TSLEntity.

TSLEntity objects obtained from a TSLMapDataLayer are read-only. The user should not delete the TSLEntity objects returned by the query, since they are embedded within the Data Layer.

Parameters

index

Index into list of required TSLEntity

Returns

NULL if index is out of range, TSLEntity otherwise.

size()

int TSLMapQuery::size

(

)

const

Query the number of TSLEntitySets contained in the query.