The EntityComponentManager constructs, deletes, and returns components and entities. A component can be of any class which inherits from components::BaseComponent. More...

#include <ignition/gazebo/EntityComponentManager.hh>

Classes
struct	identity
	why is this required? More...

Public Member Functions
	EntityComponentManager ()
	Constructor. More...

	~EntityComponentManager ()
	Destructor. More...

template<typename ... ComponentTypeTs>
std::vector< Entity >	ChildrenByComponents (Entity _parent, const ComponentTypeTs &..._desiredComponents) const
	Get all entities which match the value of all the given components and are immediate children of a given parent entity. For example, the following will return a child of entity `parent` which has an int component equal to 123, and a string component equal to "name": More...

template<typename ComponentTypeT >
const ComponentTypeT *	Component (const Entity _entity) const
	Get a component assigned to an entity based on a component type. More...

template<typename ComponentTypeT >
ComponentTypeT *	Component (const Entity _entity)
	Get a mutable component assigned to an entity based on a component type. More...

template<typename ComponentTypeT >
const ComponentTypeT *	Component (const ComponentKey &_key) const
	Get a component based on a key. More...

template<typename ComponentTypeT >
ComponentTypeT *	Component (const ComponentKey &_key)
	Get a mutable component based on a key. More...

template<typename ComponentTypeT >
ComponentKey	CreateComponent (const Entity _entity, const ComponentTypeT &_data)
	Create a component of a particular type. This will copy the _data parameter. More...

Entity	CreateEntity ()
	Creates a new Entity. More...

template<typename ... ComponentTypeTs>
void	Each (typename identity< std::function< bool(const Entity &_entity, const ComponentTypeTs *...)>>::type _f) const
	Get all entities which contain given component types, as well as the components. Note that an entity marked for removal (but not processed yet) will be included in the list of entities iterated by this call. More...

template<typename ... ComponentTypeTs>
void	Each (typename identity< std::function< bool(const Entity &_entity, ComponentTypeTs *...)>>::type _f)
	Get all entities which contain given component types, as well as the mutable components. Note that an entity marked for removal (but not processed yet) will be included in the list of entities iterated by this call. More...

template<typename... ComponentTypeTs>
void	EachNew (typename identity< std::function< bool(const Entity &_entity, ComponentTypeTs *...)>>::type _f)
	Get all newly created entities which contain given component types, as well as the components. This "newness" is cleared at the end of a simulation step. More...

template<typename... ComponentTypeTs>
void	EachNew (typename identity< std::function< bool(const Entity &_entity, const ComponentTypeTs *...)>>::type _f) const
	Get all newly created entities which contain given component types, as well as the components. This "newness" is cleared at the end of a simulation step. This is the const version. More...

template<typename ... ComponentTypeTs>
void	EachNoCache (typename identity< std::function< bool(const Entity &_entity, const ComponentTypeTs *...)>>::type _f) const
	A version of Each() that doesn't use a cache. The cached version, Each(), is preferred. Get all entities which contain given component types, as well as the components. More...

template<typename ... ComponentTypeTs>
void	EachNoCache (typename identity< std::function< bool(const Entity &_entity, ComponentTypeTs *...)>>::type _f)
	A version of Each() that doesn't use a cache. The cached version, Each(), is preferred. Get all entities which contain given component types, as well as the mutable components. More...

template<typename ... ComponentTypeTs>
void	EachRemoved (typename identity< std::function< bool(const Entity &_entity, const ComponentTypeTs *...)>>::type _f) const
	Get all entities which contain given component types and are about to be removed, as well as the components. More...

const EntityGraph &	Entities () const
	Get a graph with all the entities. Entities are vertices and edges point from parent to children. More...

template<typename ... ComponentTypeTs>
Entity	EntityByComponents (const ComponentTypeTs &..._desiredComponents) const
	Get an entity which matches the value of all the given components. For example, the following will return the entity which has an int component equal to 123, and a string component equal to "name": More...

size_t	EntityCount () const
	Get the number of entities on the server. More...

bool	EntityHasComponent (const Entity _entity, const ComponentKey &_key) const
	Check whether an entity has a specific component. More...

bool	EntityHasComponentType (const Entity _entity, const ComponentTypeId &_typeId) const
	Check whether an entity has a specific component type. More...

bool	EntityMatches (Entity _entity, const std::set< ComponentTypeId > &_types) const
	Get whether an entity has all the given component types. More...

template<typename ComponentTypeT >
const ComponentTypeT *	First () const
	The first component instance of the specified type. More...

template<typename ComponentTypeT >
ComponentTypeT *	First ()
	The first component instance of the specified type. More...

bool	HasComponentType (const ComponentTypeId _typeId) const
	Get whether a component type has ever been created. More...

bool	HasEntity (const Entity _entity) const
	Get whether an Entity exists. More...

Entity	ParentEntity (const Entity _entity) const
	Get the first parent of the given entity. Entities are not expected to have multiple parents. TODO(louise) Either prevent multiple parents or provide full support for multiple parents. More...

void	RebuildViews ()
	Rebuild all the views. This could be an expensive operation. More...

bool	RemoveComponent (const Entity _entity, const ComponentKey &_key)
	Remove a component from an entity based on a key. More...

bool	RemoveComponent (const Entity _entity, const ComponentTypeId &_typeId)
	Remove a component from an entity based on a type id. More...

template<typename ComponentTypeT >
bool	RemoveComponent (Entity _entity)
	Remove a component from an entity based on a type. More...

void	RequestRemoveEntities ()
	Request to remove all entities. This will insert the request into a queue. The queue is processed toward the end of a simulation update step. More...

void	RequestRemoveEntity (const Entity _entity, bool _recursive=true)
	Request an entity deletion. This will insert the request into a queue. The queue is processed toward the end of a simulation update step. More...

bool	SetParentEntity (const Entity _child, const Entity _parent)
	Set the parent of an entity. More...

Static Public Member Functions
template<class Function , class... ComponentTypeTs>
static void	ForEach (Function _f, const ComponentTypeTs &... _components)
	Call a function for each parameter in a pack. More...

Protected Member Functions
void	ClearNewlyCreatedEntities ()
	Clear the list of newly added entities so that a call to EachAdded after this will have no entities to iterate. This function is protected to facilitate testing. More...

void	ProcessRemoveEntityRequests ()
	Process all entity remove requests. This will remove entities and their components. This function is protected to facilitate testing. More...

Detailed Description

The EntityComponentManager constructs, deletes, and returns components and entities. A component can be of any class which inherits from components::BaseComponent.

Constructor & Destructor Documentation

◆ EntityComponentManager()

EntityComponentManager ( )

Constructor.

◆ ~EntityComponentManager()

~EntityComponentManager ( )

Destructor.

Member Function Documentation

◆ ChildrenByComponents()

std::vector< Entity > ChildrenByComponents	(	Entity	_parent,
		const ComponentTypeTs &...	_desiredComponents
	)		const

Get all entities which match the value of all the given components and are immediate children of a given parent entity. For example, the following will return a child of entity parent which has an int component equal to 123, and a string component equal to "name":

auto entity = ChildrenByComponents(parent, 123, std::string("name"));

Component type must have inequality operator.

Parameters

[in]	_parent	Entity which should be an immediate parent of the returned entity.
[in]	_desiredComponents	All the components which must match.

Returns: All matching entities, or an empty vector if no child entity has the exact components.

References EntityComponentManager::Component(), EntityComponentManager::Entities(), and EntityComponentManager::ForEach().

◆ ClearNewlyCreatedEntities()

void ClearNewlyCreatedEntities ( )

protected

Clear the list of newly added entities so that a call to EachAdded after this will have no entities to iterate. This function is protected to facilitate testing.

◆ Component() [1/4]

const ComponentTypeT * Component ( const Entity _entity ) const

Get a component assigned to an entity based on a component type.

Parameters

[in] _entity The entity.

Returns: The component of the specified type assigned to specified Entity, or nullptr if the component could not be found.

Referenced by EntityComponentManager::ChildrenByComponents(), and EntityComponentManager::EntityByComponents().

◆ Component() [2/4]

ComponentTypeT * Component ( const Entity _entity )

Get a mutable component assigned to an entity based on a component type.

Parameters

[in] _entity The entity.

Returns: The component of the specified type assigned to specified Entity, or nullptr if the component could not be found.

◆ Component() [3/4]

const ComponentTypeT * Component ( const ComponentKey & _key ) const

Get a component based on a key.

Parameters

[in] _key A key that uniquely identifies a component.

Returns: The component associated with the key, or nullptr if the component could not be found.

◆ Component() [4/4]

ComponentTypeT * Component ( const ComponentKey & _key )

Get a mutable component based on a key.

Parameters

[in] _key A key that uniquely identifies a component.

Returns: The component associated with the key, or nullptr if the component could not be found.

◆ CreateComponent()

ComponentKey CreateComponent	(	const Entity	_entity,
		const ComponentTypeT &	_data
	)

Create a component of a particular type. This will copy the _data parameter.

Parameters

[in]	_entity	The entity that will be associated with the component.
[in]	_data	Data used to construct the component.

Returns: Key that uniquely identifies the component.

◆ CreateEntity()

Entity CreateEntity ( )

Creates a new Entity.

Returns: An id for the Entity, or kNullEntity on failure.

◆ Each() [1/2]

void Each ( typename identity< std::function< bool(const Entity &_entity, const ComponentTypeTs *...)>>::type _f ) const

Get all entities which contain given component types, as well as the components. Note that an entity marked for removal (but not processed yet) will be included in the list of entities iterated by this call.

Parameters

[in] _f Callback function to be called for each matching entity. The function parameter are all the desired component types, in the order they're listed on the template. The callback function can return false to stop subsequent calls to the callback, otherwise a true value should be returned.

Template Parameters

ComponentTypeTs All the desired component types.

Warning: This function should not be called outside of System's PreUpdate, Update, or PostUpdate callbacks.

◆ Each() [2/2]

void Each ( typename identity< std::function< bool(const Entity &_entity, ComponentTypeTs *...)>>::type _f )

Get all entities which contain given component types, as well as the mutable components. Note that an entity marked for removal (but not processed yet) will be included in the list of entities iterated by this call.

Parameters

[in] _f Callback function to be called for each matching entity. The function parameter are all the desired component types, in the order they're listed on the template. The callback function can return false to stop subsequent calls to the callback, otherwise a true value should be returned.

Template Parameters

ComponentTypeTs All the desired mutable component types.

Warning: This function should not be called outside of System's PreUpdate, Update, or PostUpdate callbacks.

◆ EachNew() [1/2]

void EachNew ( typename identity< std::function< bool(const Entity &_entity, ComponentTypeTs *...)>>::type _f )

Get all newly created entities which contain given component types, as well as the components. This "newness" is cleared at the end of a simulation step.

Parameters

[in] _f Callback function to be called for each matching entity. The function parameter are all the desired component types, in the order they're listed on the template. The callback function can return false to stop subsequent calls to the callback, otherwise a true value should be returned.

Template Parameters

ComponentTypeTs All the desired component types.

Warning: This function should not be called outside of System's PreUpdate, callback. The result of call after PreUpdate is invalid

◆ EachNew() [2/2]

void EachNew ( typename identity< std::function< bool(const Entity &_entity, const ComponentTypeTs *...)>>::type _f ) const

Get all newly created entities which contain given component types, as well as the components. This "newness" is cleared at the end of a simulation step. This is the const version.

Parameters

[in] _f Callback function to be called for each matching entity. The function parameter are all the desired component types, in the order they're listed on the template. The callback function can return false to stop subsequent calls to the callback, otherwise a true value should be returned.

Template Parameters

ComponentTypeTs All the desired component types.

Warning: This function should not be called outside of System's PreUpdate, callback. The result of call after PreUpdate is invalid

◆ EachNoCache() [1/2]

void EachNoCache ( typename identity< std::function< bool(const Entity &_entity, const ComponentTypeTs *...)>>::type _f ) const

A version of Each() that doesn't use a cache. The cached version, Each(), is preferred. Get all entities which contain given component types, as well as the components.

Parameters

[in] _f Callback function to be called for each matching entity. The function parameter are all the desired component types, in the order they're listed on the template. The callback function can return false to stop subsequent calls to the callback, otherwise a true value should be returned.

Template Parameters

ComponentTypeTs All the desired component types.

Warning: This function should not be called outside of System's PreUpdate, Update, or PostUpdate callbacks.

References EntityComponentManager::Entities(), and EntityComponentManager::EntityMatches().

◆ EachNoCache() [2/2]

void EachNoCache ( typename identity< std::function< bool(const Entity &_entity, ComponentTypeTs *...)>>::type _f )

A version of Each() that doesn't use a cache. The cached version, Each(), is preferred. Get all entities which contain given component types, as well as the mutable components.

Parameters

[in] _f Callback function to be called for each matching entity. The function parameter are all the desired component types, in the order they're listed on the template. The callback function can return false to stop subsequent calls to the callback, otherwise a true value should be returned.

Template Parameters

ComponentTypeTs All the desired mutable component types.

Warning: This function should not be called outside of System's PreUpdate, Update, or PostUpdate callbacks.

References EntityComponentManager::Entities(), and EntityComponentManager::EntityMatches().

◆ EachRemoved()

void EachRemoved ( typename identity< std::function< bool(const Entity &_entity, const ComponentTypeTs *...)>>::type _f ) const

Get all entities which contain given component types and are about to be removed, as well as the components.

Parameters

[in] _f Callback function to be called for each matching entity. The function parameter are all the desired component types, in the order they're listed on the template. The callback function can return false to stop subsequent calls to the callback, otherwise a true value should be returned.

Template Parameters

ComponentTypeTs All the desired component types.

Warning: This function should not be called outside of System's PreUpdate, callback. The result of call after PreUpdate is invalid

References EntityComponentManager::Entities(), and EntityComponentManager::EntityMatches().

◆ Entities()

const EntityGraph& Entities ( ) const

Get a graph with all the entities. Entities are vertices and edges point from parent to children.

Returns: Entity graph.

Referenced by EntityComponentManager::ChildrenByComponents(), EntityComponentManager::EachNoCache(), and EntityComponentManager::EachRemoved().

◆ EntityByComponents()

Entity EntityByComponents ( const ComponentTypeTs &... _desiredComponents ) const

Get an entity which matches the value of all the given components. For example, the following will return the entity which has an int component equal to 123, and a string component equal to "name":

auto entity = EntityByComponents(123, std::string("name"));

Component type must have inequality operator.

Parameters

[in] _desiredComponents All the components which must match.

Returns: Entity or kNullEntity if no entity has the exact components.

References EntityComponentManager::Component(), EntityComponentManager::ForEach(), and ignition::gazebo::kNullEntity.

◆ EntityCount()

size_t EntityCount ( ) const

Get the number of entities on the server.

Returns: Entity count.

◆ EntityHasComponent()

bool EntityHasComponent	(	const Entity	_entity,
		const ComponentKey &	_key
	)		const

Check whether an entity has a specific component.

Parameters

[in]	_entity	The entity to check.
[in]	_key	The component to check.

Returns: True if the component key belongs to the entity.

◆ EntityHasComponentType()

bool EntityHasComponentType	(	const Entity	_entity,
		const ComponentTypeId &	_typeId
	)		const

Check whether an entity has a specific component type.

Parameters

[in]	_entity	The entity to check.
[in]	_typeId	Component type id to check.

Returns: True if the entity exists and has at least one component with the provided type.

◆ EntityMatches()

bool EntityMatches	(	Entity	_entity,
		const std::set< ComponentTypeId > &	_types
	)		const

Get whether an entity has all the given component types.

Parameters

[in]	_entity	The entity to check.
[in]	_types	Component types to check that the Entity has.

Returns: True if the given entity has all the given types.

Referenced by EntityComponentManager::EachNoCache(), and EntityComponentManager::EachRemoved().

◆ First() [1/2]

const ComponentTypeT * First ( ) const

The first component instance of the specified type.

Returns: First component instance of the specified type, or nullptr if the type does not exist.

Referenced by EntityComponentManager::First().

◆ First() [2/2]

ComponentTypeT * First ( )

The first component instance of the specified type.

Returns: First component instance of the specified type, or nullptr if the type does not exist.

References EntityComponentManager::First().

◆ ForEach()

void ForEach	(	Function	_f,
		const ComponentTypeTs &...	_components
	)

static

Call a function for each parameter in a pack.

Parameters

[in]	_f	Function to be called.
[in]	_components	Parameters which should be passed to the function.

Referenced by EntityComponentManager::ChildrenByComponents(), and EntityComponentManager::EntityByComponents().

◆ HasComponentType()

bool HasComponentType ( const ComponentTypeId _typeId ) const

Get whether a component type has ever been created.

Parameters

[in] _typeId ID of the component type to check.

Returns: True if the provided _typeId has been created.

◆ HasEntity()

bool HasEntity ( const Entity _entity ) const

Get whether an Entity exists.

Parameters

[in] _entity Entity to confirm.

Returns: True if the Entity exists.

◆ ParentEntity()

Entity ParentEntity ( const Entity _entity ) const

Get the first parent of the given entity. Entities are not expected to have multiple parents. TODO(louise) Either prevent multiple parents or provide full support for multiple parents.

Parameters

[in] _entity Entity.

Returns: The parent entity or kNullEntity if there's none.

◆ ProcessRemoveEntityRequests()

void ProcessRemoveEntityRequests ( )

protected

Process all entity remove requests. This will remove entities and their components. This function is protected to facilitate testing.

◆ RebuildViews()

void RebuildViews ( )

Rebuild all the views. This could be an expensive operation.

◆ RemoveComponent() [1/3]

bool RemoveComponent	(	const Entity	_entity,
		const ComponentKey &	_key
	)

Remove a component from an entity based on a key.

Parameters

[in]	_entity	The entity.
[in]	_key	A key that uniquely identifies a component.

Returns: True if the entity and component existed and the component was removed.

Referenced by EntityComponentManager::RemoveComponent().

◆ RemoveComponent() [2/3]

bool RemoveComponent	(	const Entity	_entity,
		const ComponentTypeId &	_typeId
	)

Remove a component from an entity based on a type id.

Parameters

[in]	_entity	The entity.
[in]	_typeId	Component's type Id.

Returns: True if the entity and component existed and the component was removed.

◆ RemoveComponent() [3/3]

bool RemoveComponent ( Entity _entity )

Remove a component from an entity based on a type.

Parameters

[in] _entity The entity.

Template Parameters

Component type.

Returns: True if the entity and component existed and the component was removed.

References EntityComponentManager::RemoveComponent().

◆ RequestRemoveEntities()

void RequestRemoveEntities ( )

Request to remove all entities. This will insert the request into a queue. The queue is processed toward the end of a simulation update step.

◆ RequestRemoveEntity()

void RequestRemoveEntity	(	const Entity	_entity,
		bool	_recursive = `true`
	)

Request an entity deletion. This will insert the request into a queue. The queue is processed toward the end of a simulation update step.

It is recommended that systems don't call this function directly, and instead use the gazebo::SdfEntityCreator class to remove entities.

Parameters

[in]	_entity	Entity to be removed.
[in]	_recursive	Whether to recursively delete all child entities. True by default.

◆ SetParentEntity()

bool SetParentEntity	(	const Entity	_child,
		const Entity	_parent
	)

Set the parent of an entity.

It is recommended that systems don't call this function directly, and instead use the gazebo::SdfEntityCreator class to create entities that have the correct parent-child relationship.

Parameters

[in] _entity Entity or kNullEntity to remove current parent.

Returns: True if successful. Will fail if entities don't exist.

The documentation for this class was generated from the following file:

EntityComponentManager.hh

Classes

Public Member Functions

Static Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ EntityComponentManager()

◆ ~EntityComponentManager()

Member Function Documentation

◆ ChildrenByComponents()

◆ ClearNewlyCreatedEntities()

◆ Component() [1/4]

◆ Component() [2/4]

◆ Component() [3/4]

◆ Component() [4/4]

◆ CreateComponent()

◆ CreateEntity()

◆ Each() [1/2]

◆ Each() [2/2]

◆ EachNew() [1/2]

◆ EachNew() [2/2]

◆ EachNoCache() [1/2]

◆ EachNoCache() [2/2]

◆ EachRemoved()

◆ Entities()

◆ EntityByComponents()

◆ EntityCount()

◆ EntityHasComponent()

◆ EntityHasComponentType()

◆ EntityMatches()

◆ First() [1/2]

◆ First() [2/2]

◆ ForEach()

◆ HasComponentType()

◆ HasEntity()

◆ ParentEntity()

◆ ProcessRemoveEntityRequests()

◆ RebuildViews()

◆ RemoveComponent() [1/3]

◆ RemoveComponent() [2/3]

◆ RemoveComponent() [3/3]

◆ RequestRemoveEntities()

◆ RequestRemoveEntity()

◆ SetParentEntity()