TAO_RTEvent  2.0.8
Public Types | Public Member Functions | Static Public Member Functions | Private Attributes
TAO_EC_Filter Class Reference

Abstract base class for the filter hierarchy. More...

#include <EC_Filter.h>

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List of all members.

Public Types

typedef TAO_EC_Filtervalue_type
typedef TAO_EC_Filter *const const_value_type
typedef const_value_typeChildrenIterator

Public Member Functions

 TAO_EC_Filter (void)
 constructor...
virtual ~TAO_EC_Filter (void)
 destructor...
TAO_EC_Filterparent (void) const
 Obtain the parent of this filter.
void adopt_child (TAO_EC_Filter *child)
 Become the parent of child.
virtual ChildrenIterator begin (void) const
virtual ChildrenIterator end (void) const
virtual int size (void) const
virtual int filter (const RtecEventComm::EventSet &event, TAO_EC_QOS_Info &qos_info)=0
virtual int filter_nocopy (RtecEventComm::EventSet &event, TAO_EC_QOS_Info &qos_info)=0
virtual void push (const RtecEventComm::EventSet &event, TAO_EC_QOS_Info &qos_info)=0
virtual void push_nocopy (RtecEventComm::EventSet &event, TAO_EC_QOS_Info &qos_info)=0
virtual void clear (void)=0
virtual CORBA::ULong max_event_size (void) const =0
 Returns the maximum size of the events pushed by this filter.
virtual int can_match (const RtecEventComm::EventHeader &header) const =0
virtual int add_dependencies (const RtecEventComm::EventHeader &header, const TAO_EC_QOS_Info &qos_info)=0
virtual void get_qos_info (TAO_EC_QOS_Info &qos_info)

Static Public Member Functions

static int matches (const RtecEventComm::EventHeader &rhs, const RtecEventComm::EventHeader &lhs)

Private Attributes

TAO_EC_Filterparent_
 The parent...

Detailed Description

Abstract base class for the filter hierarchy.

The per-consumer filtering mechanisms. The EC needs to filter data passed to the consumers, so it can correctly satisfy its subscription requirements. This filtering can include correlations, sequences, timeouts, etc. each consumer can request different filtering criteria. Different filtering objects are associated with each consumer, the filters are organized in a hierarchical structure, corresponding to the subscription "expression" that the events must satisfy. The hierarchy is constructed using the "Builder" pattern.

Memory Management

It does *not* assume ownership of its parent.


Member Typedef Documentation


Constructor & Destructor Documentation

TAO_EC_Filter::TAO_EC_Filter ( void  )

constructor...

TAO_EC_Filter::~TAO_EC_Filter ( void  ) [virtual]

destructor...


Member Function Documentation

virtual int TAO_EC_Filter::add_dependencies ( const RtecEventComm::EventHeader header,
const TAO_EC_QOS_Info qos_info 
) [pure virtual]

This is used for computing the scheduling dependencies:

Leaf filters check if the header could be matched, similar to the can_match() method; if it does they return 1, and 0 otherwise. Intermediate nodes always return 0.

This is used to build precise dependencies between the suppliers and the leaf of the filters that accept that event. Notice that only the nodes doing scheduling recurse through the list, so in configurations that do no require scheduling the recursion stops fairly soon.

Implemented in TAO_EC_Null_Filter, TAO_EC_ProxyPushSupplier, TAO_EC_Bitmask_Filter, TAO_EC_Kokyu_Filter, TAO_EC_Sched_Filter, TAO_EC_Timeout_Filter, TAO_EC_Conjunction_Filter, TAO_EC_Masked_Type_Filter, TAO_EC_Disjunction_Filter, TAO_EC_And_Filter, TAO_EC_Negation_Filter, and TAO_EC_Type_Filter.

void TAO_EC_Filter::adopt_child ( TAO_EC_Filter child)

Become the parent of child.

TAO_EC_Filter::ChildrenIterator TAO_EC_Filter::begin ( void  ) const [virtual]

STL-like iterators Filters follow the Composite pattern. All filters expose the same interface as if they all had children, but for simple filters the iterators return an empty range.

Reimplemented in TAO_EC_Bitmask_Filter, TAO_EC_Kokyu_Filter, TAO_EC_Sched_Filter, TAO_EC_Conjunction_Filter, TAO_EC_Masked_Type_Filter, TAO_EC_Disjunction_Filter, TAO_EC_And_Filter, and TAO_EC_Negation_Filter.

virtual int TAO_EC_Filter::can_match ( const RtecEventComm::EventHeader header) const [pure virtual]

Returns 0 if an event with that header could never be accepted. This can used by the suppliers to filter out consumers that couldn't possibly be interested in their events. The rt_info and

Implemented in TAO_EC_Null_Filter, TAO_EC_ProxyPushSupplier, TAO_EC_Bitmask_Filter, TAO_EC_Kokyu_Filter, TAO_EC_Sched_Filter, TAO_EC_Timeout_Filter, TAO_EC_Conjunction_Filter, TAO_EC_Masked_Type_Filter, TAO_EC_Disjunction_Filter, TAO_EC_And_Filter, TAO_EC_Negation_Filter, and TAO_EC_Type_Filter.

virtual void TAO_EC_Filter::clear ( void  ) [pure virtual]
TAO_EC_Filter::ChildrenIterator TAO_EC_Filter::end ( void  ) const [virtual]
virtual int TAO_EC_Filter::filter ( const RtecEventComm::EventSet event,
TAO_EC_QOS_Info qos_info 
) [pure virtual]

Filter this event, returns 1 if the event is accepted, 0 otherwise. Notice that there are two versions of the method, if the event is not const then filter can take ownership of the event.

Attention:
There seems to be a disparity in interfaces: Supplier always push event sets of size 1 to the EC_ProxyPushSupplier, and EC_Filters do not implement handling of sets of more than 1 event. Then, why is this not enforced by the interface by having EC_ProxyPushSupplier take an event rather than a set?

Implemented in TAO_EC_Null_Filter, TAO_EC_ProxyPushSupplier, TAO_EC_Bitmask_Filter, TAO_EC_Kokyu_Filter, TAO_EC_Sched_Filter, TAO_EC_Timeout_Filter, TAO_EC_Conjunction_Filter, TAO_EC_Masked_Type_Filter, TAO_EC_Disjunction_Filter, TAO_EC_And_Filter, TAO_EC_Negation_Filter, and TAO_EC_Type_Filter.

virtual int TAO_EC_Filter::filter_nocopy ( RtecEventComm::EventSet event,
TAO_EC_QOS_Info qos_info 
) [pure virtual]
void TAO_EC_Filter::get_qos_info ( TAO_EC_QOS_Info qos_info) [virtual]

Obtain the QOS information for this filter, the default implementation returns an invalid QOS. Only the filters that support scheduling information implement this method.

Returns:
Returns 0 on success and -1 on failure

Reimplemented in TAO_EC_Kokyu_Filter, and TAO_EC_Sched_Filter.

int TAO_EC_Filter::matches ( const RtecEventComm::EventHeader rhs,
const RtecEventComm::EventHeader lhs 
) [static]

Matches two event headers.

Todo:
Should we strategize the algorithm used to match headers?
virtual CORBA::ULong TAO_EC_Filter::max_event_size ( void  ) const [pure virtual]
TAO_EC_Filter * TAO_EC_Filter::parent ( void  ) const

Obtain the parent of this filter.

virtual void TAO_EC_Filter::push ( const RtecEventComm::EventSet event,
TAO_EC_QOS_Info qos_info 
) [pure virtual]

This is called by the children when they accept an event and which to pass it up. Notice that there are two versions of the method, if the event is not const then filter can take ownership of the event.

Implemented in TAO_EC_Null_Filter, TAO_EC_ProxyPushSupplier, TAO_EC_Bitmask_Filter, TAO_EC_Kokyu_Filter, TAO_EC_Sched_Filter, TAO_EC_Timeout_Filter, TAO_EC_Conjunction_Filter, TAO_EC_Masked_Type_Filter, TAO_EC_Disjunction_Filter, TAO_EC_And_Filter, TAO_EC_Negation_Filter, and TAO_EC_Type_Filter.

virtual void TAO_EC_Filter::push_nocopy ( RtecEventComm::EventSet event,
TAO_EC_QOS_Info qos_info 
) [pure virtual]
int TAO_EC_Filter::size ( void  ) const [virtual]

Member Data Documentation

The parent...


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