WebSphere WebSphere Enterprise Service Bus, Version 6.0.1 Operating Systems: AIX, HP-UX, Linux, Solaris, Windows

Event catalog inheritance

Event definitions inherit the properties of their parents.

By default, an event definition inherits the property descriptions and extended data element descriptions of its parent. However, a child event definition can override these inherited descriptions, subject to certain restrictions. When you add an event definition to the event catalog, the catalog verifies that the new event definition does not violate the rules governing inheritance; if it does, an InheritanceNotValidException exception is thrown. Similarly, if you replace an existing event definition that has descendants, the event catalog verifies the validity of the existing inheritance relationships and throws an InheritanceNotValidException exception if any of them are no longer valid. In either case, the new event definition is not added to the catalog unless all inheritance relationships are valid.

An event definition can exist in either of two forms, unresolved and resolved:

Overriding inherited property descriptions

A child event definition inherits each property description from its parent without change unless it already has a locally defined property description of the same name and path (note that case is significant). If the child has a property description of the same name and path, the fields of the child description can override the fields of the parent description as follows:
Default value
The child can override the default value specified by the parent property description. If the child does not specify a default value, it inherits the value from the parent.
Required or optional
The child always overrides the parent. However, if the parent defines a property as required, the child must also specify that it is required. An inherited required property cannot be redefined as optional.
Permitted values or minimum and maximum values
If the parent defines permitted values or minimum and maximum values, the child can override these by specifying either permitted values or minimum and maximum values. Note that an event definition can contain only permitted values or minimum and maximum values, not both:
  • If the parent defines minimum and maximum values, but the child defines permitted values, the minimum and maximum values defined by the parent are ignored.
  • If the parent defines permitted values, but the child defines minimum and maximum values, the permitted values defined by the parent are ignored.
  • If the parent defines only a maximum value, but the child defines only a minimum value, the child inherits the maximum value defined by the parent.
  • If the child does not specify permitted values or minimum and maximum values, the values specified by the parent are inherited.

Overriding inherited extended data element descriptions

A child event definition inherits each extended data element description from its parent without change unless it already has a locally defined extended data element description of the same name. If the child does have an extended data element description of the same name, the fields of the child description can override the fields of the parent description as follows:
Type
The child must specify the same type as the parent.
Minimum occurrence
The child always overrides the parent.
Maximum occurrence
The child always overrides the parent.
Default values
The child can override the default values specified by the parent extended data element description. If the child does not specify default values, it inherits the values from the parent.
Default hexadecimal value
The child can override the default hexadecimal value specified by the parent extended data element description. If the child does not specify a default hexadecimal value, it inherits the value from the parent.
Nested extended data element description
The child can override a nested extended data element description by defining a nested description of the same name. If the child overrides an inherited nested description, the same rules apply to overriding the individual fields. If the child does not specify a nested extended data element description of the same name, it inherits the nested description from the parent.

Concept topic

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Timestamp iconLast updated: 13 Dec 2005
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