org.apache.openjpa.kernel.exps
public interface AggregateListener extends java.io.Serializable
Modifier and Type | Method and Description |
---|---|
java.lang.Object |
evaluate(java.util.Collection args,
java.lang.Class[] argClasses,
java.util.Collection candidates,
StoreContext ctx)
Return the value of this aggregate.
|
boolean |
expectsArguments()
Return whether this function expects to act on arguments.
|
java.lang.String |
getTag()
Return the tag that this listener listens for.
|
java.lang.Class |
getType(java.lang.Class[] argClasses)
Return the expected type of the result of this listener.
|
java.lang.String getTag()
boolean expectsArguments()
count()
.java.lang.Object evaluate(java.util.Collection args, java.lang.Class[] argClasses, java.util.Collection candidates, StoreContext ctx)
args
- for each candidate, the value of the arguments to
the function; will be null if this aggregate does
not expect an argument; if this function has
multiple arguments, each element will be an arrayargClasses
- the expected class of each argument elementcandidates
- the candidate objects being evaluatedctx
- the persistence contextUserException
- if this aggregate does not
support in-memory operationjava.lang.Class getType(java.lang.Class[] argClasses)
argClasses
- the expected classes of the argument, or null if
no arguments