org.omg.CosNotifyFilter
Interface MappingFilterOperations

All Known Subinterfaces:

MappingFilter

public interface MappingFilterOperations

The MappingFilter interface defines the behaviors of objects, which encapsulate a sequence of constraint-value pairs, where each value represents a possible setting of a particular property of an event. Note that setting of a particular property is not intended to imply that any contents of the event will be altered as a result of applying a mapping filter, but rather the way a proxy treats the event with respect to a particular property could change. Upon receiving each event, a proxy object with an associated object supporting the MappingFilter interface will invoke the appropriate match operation variant (depending upon whether the event is received in the form of an untyped event, a Structured Event, or a typed event) on the mapping filter object in order to determine how it should modify a particular property value associated with the event to one of the values associated with one of the constraints encapsulated by the mapping filter. Internally, the mapping filter object applies the constraints it encapsulates to the event in order to determine whether or not the event?s property should be modified to one of the values associated with a constraint, or else the default value associated with the mapping filter.

Each instance of an object supporting the MappingFilter interface is typically associated with a specific event property. For instance, in this specification MappingFilter object instances are used to affect the properties of priority and lifetime for events received by a proxy supplier object. Each event received by a proxy object, which has an object supporting the MappingFilter interface associated with it must satisfy at least one of the constraints associated with the MappingFilter object in order to have its property value modified, otherwise the property will remain unchanged. A specific instance supporting the MappingFilter interface typically applies its encapsulated constraints in an order which begins with the best possible property setting (e.g., the highest priority or the longest lifetime), and ends with the worst possible property setting. As soon as a matching constraint is encountered, the associated value is returned as an output parameter and the proxy which invoked the operation proceeds to modify the property of the event to the new value.

The constraint expressions associated with a particular object supporting the MappingFilter interface are expressed as strings which obey the syntax of a particular constraint grammar (i.e., a BNF). Implementations may support other constraint grammars, and/or users of this service may implement their own filter objects which allow constraints to be expressed in terms of an alternative constraint grammar. As long as such user-defined filter objects support the MappingFilter interface, they can be attached to proxy objects in the same fashion as the default MappingFilter objects supported by the implementation of the service are, and the channel should be able to use them to potentially affect the properties of events in the same fashion.

The MappingFilter interface supports the operations required to manage the constraint-value pairs associated with an object instance which supports the interface. In addition, the MappingFilter interface supports a readonly attribute which identifies the particular constraint grammar in which the constraints encapsulated by this object have meaning. The MappingFilter interface also supports a readonly attribute which identifies the typecode associated with the datatype of the specific property value it is intended to affect, and another readonly attribute which holds the default value which will be returned as the result of a match operation in cases when the event in question is found to satisfy none of the constraints encapsulated by the mapping filter. Lastly, the MappingFilter interface supports three variants of the operation which will be invoked by an associated proxy object upon receipt of an event, to determine how the property of the event which the target mapping filter object was designed to affect should be modified.

Method Summary

MappingConstraintInfo[]	add_mapping_constraints(MappingConstraintPair[] pair_list) The add_mapping_constraints operation is invoked by a client in order to associate specific mapping constraints with the target filter object.
java.lang.String	constraint_grammar() The constraint_grammar attribute is a readonly attribute which identifies the particular grammar within which the constraint expressions encapsulated by the target filter object have meaning.
Any	default_value() The default_value attribute is a readonly attribute that will be the output parameter returned as the result of any match operation during which the input event is found to satisfy none of the constraints encapsulated by the mapping filter.
void	destroy() The destroy operation destroys the target filter object, invalidating its object reference.
MappingConstraintInfo[]	get_all_mapping_constraints()
MappingConstraintInfo[]	get_mapping_constraints(int[] id_list) The get_mapping_constraints operation is invoked to return a sequence of a subset of the constraint-value pairs associated with the target filter object.
boolean	match_structured(StructuredEvent filterable_data, AnyHolder result_to_set) The match_structured operation is invoked on an object supporting the MappingFilter interface in order to determine how some property value of a particular event supplied to the channel in the form of a Structured Event should be modified.
boolean	match_typed(Property[] filterable_data, AnyHolder result_to_set) The match_typed operation is invoked on an object supporting the MappingFilter interface in order to determine how some property value of a particular event supplied to the channel in the form of a typed event should be modified.
boolean	match(Any filterable_data, AnyHolder result_to_set) The match operation is invoked on an object supporting the MappingFilter interface in order to determine how some property value of a particular event supplied to the channel in the form of a CORBA::Any should be modified.
void	modify_mapping_constraints(int[] del_list, MappingConstraintInfo[] modify_list) The modify_mapping_constraints operation is invoked by a client in order to modify the constraint-value pairs associated with the target filter object.
void	remove_all_mapping_constraints() The remove_all_mapping_constraints operation is invoked to remove all of the constraint-value pairs currently encapsulated by the target filter object.
TypeCode	value_type() The value_type attribute is a readonly attribute which identifies the datatype of the property value which the target mapping filter object was designed to affect.

Method Detail

match_typed

boolean match_typed(Property[] filterable_data,
                    AnyHolder result_to_set)
                    throws UnsupportedFilterableData

The match_typed operation is invoked on an object supporting the MappingFilter interface in order to determine how some property value of a particular event supplied to the channel in the form of a typed event should be modified. The act of determining whether or not a given filterable event data passes a given filter constraint is specific to the type of grammar in which the filter constraint is specified. Thus, this operation will need to be re-implemented for each supported grammar.

Parameters:

filterable_data - A sequence of name-value pairs which contains the contents of the event to be evaluated. Upon invocation, the target mapping filter object begins applying the constraints it encapsulates in order according to each constraints associated value, starting with the constraint with the best associated value for the specific property the mapping filter object was designed to affect (e.g., the highest priority, the longest lifetime, etc.), and ending with the constraint with the worst associated value.

result_to_set - An output parameter containing constraints satisfied by filterable_data. If constraint exists, the resturn value will be set to TRUE.

Returns:

A boolean value set as follows. If the input filterable data satisfies none of the constraints encapsulated by the target mapping filter object, the return value of the operation is set to FALSE, and the output parameter is set to the value of the default_value attribute associated with the target mapping filter object.

Throws:

UnsupportedFilterableData - If the input parameter contains data that the match operation is not designed to handle. An example of this would be if the filterable data contained a field whose name corresponds to a standard event field that has a numeric value, but the actual value associated with this field name within the event is a string.

match_structured

boolean match_structured(StructuredEvent filterable_data,
                         AnyHolder result_to_set)
                         throws UnsupportedFilterableData

The match_structured operation is invoked on an object supporting the MappingFilter interface in order to determine how some property value of a particular event supplied to the channel in the form of a Structured Event should be modified. The act of determining whether or not a given filterable event data passes a given filter constraint is specific to the type of grammar in which the filter constraint is specified. Thus, this operation will need to be re-implemented for each supported grammar.

Parameters:

filterable_data - A CosNotification::StructuredEvent as input, which contains the event being evaluated. Upon invocation, the target mapping filter object begins applying the constraints it encapsulates in order according to each constraints associated value, starting with the constraint with the best associated value for the specific property the mapping filter object was designed to affect (e.g., the highest priority, the longest lifetime, etc.), and ending with the constraint with the worst associated value.

result_to_set - An output parameter containing constraints satisfied by filterable_data. If constraint exists, return value wil be set to TRUE.

Returns:

A boolean value set as follows, If the input filterable data satisfies none of the constraints encapsulated by the target mapping filter object, the return value of the operation is set to FALSE, and the output parameter is set to the value of the default_value attribute associated with this target mapping filter object.

Throws:

UnsupportedFilterableData - If the input parameter contains data that this match operation is not designed to handle. An example of this would be if the filterable data contained a field whose name corresponds to a standard event field that has a numeric value, but the actual value associated with this field name within the event is a string.

match

boolean match(Any filterable_data,
              AnyHolder result_to_set)
              throws UnsupportedFilterableData

The match operation is invoked on an object supporting the MappingFilter interface in order to determine how some property value of a particular event supplied to the channel in the form of a CORBA::Any should be modified. The act of determining whether or not a given filterable event data passes a given filter constraint is specific to the type of grammar in which the filter constraint is specified. Thus, this operation will need to be re-implemented for each supported grammar.

Parameters:

filterable_data - An any as input, which contains the event being evaluated. Upon invocation, the target mapping filter object begins applying the constraints it encapsulates in order according to each constraints associated value, starting with the constraint with the best associated value for the specific property the mapping filter object was designed to affect (e.g., the highest priority, the longest lifetime, etc.), and ending with the constraint with the worst associated value.

result_to_set - An output parameter containing the values associated with the constraints satisfied by filterable_data. If constraint exists, return value will be set to TRUE.

Returns:

A boolean value set as follows. If the input filterable data satisfies none of the constraints encapsulated by the target mapping filter object, the return value of the operation is set to FALSE, and the output parameter is set to the value of the default_value attribute associated with the target mapping filter object.

Throws:

UnsupportedFilterableData - If the input parameter contains data that this match operation is not designed to handle. An example of this would be if the filterable data contained a field whose name corresponds to a standard event field that has a numeric value, but the actual value associated with this field name within the event is a string.

destroy

void destroy()

The destroy operation destroys the target filter object, invalidating its object reference.

remove_all_mapping_constraints

void remove_all_mapping_constraints()

The remove_all_mapping_constraints operation is invoked to remove all of the constraint-value pairs currently encapsulated by the target filter object. Upon completion, the target filter object will still exist but have no constraint-value pairs associated with it.

get_all_mapping_constraints

MappingConstraintInfo[] get_all_mapping_constraints()

Returns:

A sequence of structures, each of which contains one of the constraints encapsulated by the target object along with its associated value and unique identifier.

get_mapping_constraints

MappingConstraintInfo[] get_mapping_constraints(int[] id_list)
                                                throws ConstraintNotFound

The get_mapping_constraints operation is invoked to return a sequence of a subset of the constraint-value pairs associated with the target filter object.

Parameters:

id_list - A sequence of numeric values which should correspond to the unique identifiers of constraint-value pairs encapsulated by the target object.

Returns:

A sequence of data structures, each of which contains one of the input identifiers along with its associated constraint structure and constraint value.

Throws:

ConstraintNotFound - If one of the input values does not correspond to the identifier of some encapsulated constraintvalue pair. This exception contains as data the numeric value that did not correspond to some such pair.

modify_mapping_constraints

void modify_mapping_constraints(int[] del_list,
                                MappingConstraintInfo[] modify_list)
                                throws InvalidConstraint,
                                       InvalidValue,
                                       ConstraintNotFound

The modify_mapping_constraints operation is invoked by a client in order to modify the constraint-value pairs associated with the target filter object. This operation can be used both to remove constraint-value pairs currently associated with the target filter object, and to modify the constraints and/or values of constraint-value pairs which have previously been added to the target filter object.

Note that the semantics of the modify_mapping_constraints operation are such that its side-effects are performed atomically upon the target filter object. Once modify_mapping_constraints is invoked by a client, the target filter object is temporarily disabled from usage by any proxy object it may be associated with. The operation is then carried out, either successfully deleting all of the constraint-value pairs identified in the first input sequence and modifying the constraints and values associated with constraints identified in the second input sequence, or performing no side effects to the target object (in the case one of the inputs was invalid). Upon completion of the operation, the target filter object is effectively re-enabled and can once again be used by associated filter objects in order to make event property mapping decisions.

Parameters:

del_list - A sequence of numeric values which are each intended to be the unique identifier associated with one of the constraint-value pairs currently encapsulated by the target filter object. If all input values supplied within a particular invocation of this operation are valid, then the specific constraint-value pairs identified by the values contained in the first input parameter will be deleted from the list of those encapsulated by the target filter object.

modify_list - A sequence of structures, each of which contains a constraint structure, an Any value, and a numeric identifier. The numeric identifier contained by each element of the sequence is intended to be the unique identifier associated with one of the constraint-value pairs currently encapsulated by the target filter object. If all input values supplied within a particular invocation of this operation are valid, then the constraint associated with the already encapsulated constraint-value pair identified by the numeric identifier contained within each element of the input sequence will be modified to the new constraint that is contained within the same sequence element. Likewise, the data value associated with the already encapsulated constraint-value pair identified by the numeric identifier contained within each element of the input sequence will be modified to the new data value that is contained in the same element of the sequence.

Throws:

ConstraintNotFound - If any of the numeric identifiers supplied within either of the two input sequences does not correspond to the unique identifier associated with some constraint-value pairs currently encapsulated by the target filter object. This exception contains as data the specific identifier which was supplied as input but did not correspond to the identifier of some constraint-value pair encapsulated by the target object.

InvalidConstraint - If any of the constraint expressions supplied within an element of the second input sequence is not a valid expression in terms of the constraint grammar supported by the target object. This exception contains as data the specific constraint that was determined to be invalid.

InvalidValue - If any of the values supplied in the second input sequence is not of the same datatype as that indicated by the value_type attribute associated with the target object. This exception contains as data both the invalid value and its corresponding constraint expression.

add_mapping_constraints

MappingConstraintInfo[] add_mapping_constraints(MappingConstraintPair[] pair_list)
                                                throws InvalidConstraint,
                                                       InvalidValue

The add_mapping_constraints operation is invoked by a client in order to associate specific mapping constraints with the target filter object. Note that a mapping constraint is comprised of a constraint structure paired with an associated value.

Note that the semantics of the add_mapping_constraints operation are such that its side-effects are performed atomically upon the target filter object. Once add_mapping_constraints is invoked by a client, the target filter object is temporarily disabled from usage by any proxy object it may be associated with. The operation is then carried out, either successfully adding all of the input constraint-value pairs to the target object or none of them (in case one of the input expressions or values was invalid). Upon completion of the operation, the target filter object is effectively re-enabled and can once again be used by associated filter objects in order to make event property mapping decisions.

Parameters:

pair_list - A sequence of constraint-value pairs. Each constraint in this sequence must be expressed within the constraint grammar supported by the target object, and each associated value must be of the data type indicated by the value_type attribute of the target object. Upon processing each element in the input sequence, this target object associates a numeric identifier with this constraint-value pair that is unique among all those that it encapsulates.

Returns:

A sequence in which each element will be a structure including one of the input constraint expressions, its corresponding value, and the unique identifier assigned to this constraint-value pair by the target filter object.

Throws:

InvalidConstraint - If any of the constraint expressions in the input sequence is not a valid expression within the supported constraint grammar. This exception contains as data the specific constraint that was determined to be invalid.

InvalidValue - If any of the values supplied in the input sequence is not of the same datatype as that indicated by the value_type attribute associated with the target object. This exception contains as data both the invalid value and its corresponding constraint in the first input sequence.

default_value

Any default_value()

The default_value attribute is a readonly attribute that will be the output parameter returned as the result of any match operation during which the input event is found to satisfy none of the constraints encapsulated by the mapping filter. within which the constraints encapsulated by the target filter object have meaning. The value of this attribute is set upon creation of a mapping filter object instance, based on the input provided to the factory creation operation for the mapping filter instance.

value_type

TypeCode value_type()

The value_type attribute is a readonly attribute which identifies the datatype of the property value which the target mapping filter object was designed to affect. Note that the factory creation operation for mapping filter objects accepts as an input parameter the default_value to associate with the mapping filter instance. This default_value is a CORBA::Any. Upon creation of a mapping filter, the Typecode associated with the default_value is extracted from the CORBA::Any, and its value is assigned to this attribute. The value_type attribute thus serves mainly as a convenience for clients attempting to examine the state of a mapping filter object.

constraint_grammar

java.lang.String constraint_grammar()

The constraint_grammar attribute is a readonly attribute which identifies the particular grammar within which the constraint expressions encapsulated by the target filter object have meaning. The value of this attribute is set upon creation of a mapping filter object instance, based on the input provided to the factory creation operation for the mapping filter instance.

The dependency of a filter object on its constraints being expressed within a particular constraint grammar manifests itself within the implementation of the match operations described below, which must be able to parse the constraints to determine whether or not a particular event satisfies one of them.

Every conformant implementation of the Notification Service must support an implementation of the MappingFilter object. The value which the constraint_grammar attribute is set to in case the target filter object supports this default grammar will be EXTENDED_TCL. In addition, implementations and/or end users may provide additional implementations of the MappingFilter interface that support different constraint grammars, and thus would set the constraint_grammar attribute to a different value upon creation of such a filter object.