PreQuery (Google App Engine API for Java)

com.google.appengine.api.datastore

Annotation Type PreQuery


  • @Target(value=METHOD)
 @Retention(value=RUNTIME)
public @interface PreQuery
    Identifies a callback method to be invoked before a Query for any of the specified kinds is executed against the datastore. If kinds() is not provided the callback will execute for queries against all kinds, including kind-less queries. Methods with this annotation must return void, must accept a single argument of type PreQueryContext, must not throw any checked exceptions, must not be static, and must belong to a class with a no-arg constructor. Neither the method nor the no-arg constructor of the class to which it belongs are required to be public. Methods with this annotation are free to throw any unchecked exception they like. Throwing an unchecked exception will prevent callbacks that have not yet been executed from running, and the exception will propagate to the code that invoked the datastore operation that resulted in the invocation of the callback. Throwing an unchecked exception from a callback will prevent the datastore operation from executing.

    • Optional Element Summary

      Optional Elements 
      Modifier and Type Optional Element and Description
      java.lang.String[] kinds
      The kinds to which this callback applies.

    • Element Detail

      • kinds

        public abstract java.lang.String[] kinds
        The kinds to which this callback applies. The default value is an empty array, which indicates that the callback should run for all kinds.
        Returns:
        The kinds to which this callback applies.
        Default:
        {}