Abstract base class for all tag based conditions. More...

#include <Tag.h>

Inheritance diagram for osmscout::TagCondition:

Public Member Functions
virtual void	CollectTagKeys (std::vector< TagId > &keys, bool &guaranteed) const =0
	Collects the tag keys that act as primary discriminators for this condition.

virtual void	CollectTagValues (std::vector< TagValue > &values, bool &exhaustive) const
	Collects the (tag,value) pairs this condition can match for.

virtual bool	Evaluate (const TagMap &tagMap) const =0

virtual	~TagCondition ()=default

Detailed Description

Abstract base class for all tag based conditions.

Constructor & Destructor Documentation

◆ ~TagCondition()

virtual osmscout::TagCondition::~TagCondition ( )

virtualdefault

Member Function Documentation

◆ CollectTagKeys()

virtual void osmscout::TagCondition::CollectTagKeys	(	std::vector< TagId > &	keys,
		bool &	guaranteed
	)		const

pure virtual

Collects the tag keys that act as primary discriminators for this condition.

If 'guaranteed' is true, at least one of the returned keys is guaranteed to be present in the tag map whenever this condition evaluates to true, i.e. the condition can only match objects that carry one of these keys. If 'guaranteed' is false, the condition may evaluate to true even if none of the returned keys is present (e.g. conditions containing negation) and the caller has to always evaluate the condition.

Implemented in osmscout::TagNotCondition, osmscout::TagBoolCondition, osmscout::TagExistsCondition, osmscout::TagBinaryCondition, and osmscout::TagIsInCondition.

◆ CollectTagValues()

virtual void osmscout::TagCondition::CollectTagValues	(	std::vector< TagValue > &	values,
		bool &	exhaustive
	)		const

inlinevirtual

Collects the (tag,value) pairs this condition can match for.

If 'exhaustive' is true, the condition cannot evaluate to true unless the tag map carries at least one of the returned (tag,value) pairs, i.e. the returned pairs are a conservative superset of the values that can make it match. If 'exhaustive' is false, the condition may match for a value that is not listed (e.g. an existence, ordering or negated condition) and has to be evaluated for every object that carries one of its keys.

The default reports no pairs and is not exhaustive, which is always safe.

Reimplemented in osmscout::TagNotCondition, osmscout::TagBoolCondition, osmscout::TagExistsCondition, osmscout::TagBinaryCondition, and osmscout::TagIsInCondition.

◆ Evaluate()

virtual bool osmscout::TagCondition::Evaluate ( const TagMap & tagMap ) const