org.eclipse.persistence.queries
Interface QueryRedirector

All Superinterfaces:

java.io.Serializable

All Known Implementing Classes:

MethodBaseQueryRedirector

public interface QueryRedirector
extends java.io.Serializable

Purpose: Query redirection allows for a named or parameterized query (or finder) to dynamically determine how the query is to be executed based on the arguments.

Description: An implementor of this interface can be given to a query to allow the user to have full control over the execution of the query. Redirection can be used to:

• Dynamically configure the query options based on the arguments (i.e. ordering, query optimization... etc.).
• Dynamically define the selection criteria based on the arguments.
• Pass Query By Example objects or Expressions as the arguments.
• Post process the query results.
• Perform multiple queries or non-EclipseLink operations.

Note: If you execute the query on a UnitOfWork, the results register with that UnitOfWork, so any objects you attempt to retrieve with the invoke method must come from the Session Cache.

See Also:

MethodBaseQueryRedirector, DatabaseQuery.setRedirector(org.eclipse.persistence.queries.QueryRedirector)

Author:

James Sutherland

Since:

TOPLink/Java 3.0

Method Summary

java.lang.Object

invokeQuery(DatabaseQuery query, Record arguments, Session session) REQUIRED: Perform the query.

Method Detail

invokeQuery

java.lang.Object invokeQuery(DatabaseQuery query,
                             Record arguments,
                             Session session)

REQUIRED: Perform the query. This must execute the query base on the arguments and return a valid result for the query.