/*
* Copyright 2004-2009 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.compass.core;
/**
* Callback interface for Compass code. To be used with CompassTemplate's
* execute methods, assumably often as anonymous classes within a method
* implementation. The typical implementation will call
* CompassSession.load/find/save to perform some operations on searchable
* objects.
*
* @author kimchy
*/
public interface CompassCallback<T> {
/**
* Gets called by <code>CompassTemplate.execute</code> with an active
* Compass Session. Does not need to care about activating or closing the
* Session, or handling transactions.
*
* <p>If called within a thread-bound Compass transaction (initiated by an
* outer compass transaction abstraction), the code will simply get executed
* on the outer compass transaction with its transactional semantics.
*
* <p>Allows for returning a result object created within the callback, i.e. a
* domain object or a hits of domain objects. Note that there's special
* support for single step actions: see CompassTemplate.find etc. A thrown
* RuntimeException is treated as application exception, it gets propagated
* to the caller of the template.
*/
T doInCompass(CompassSession session) throws CompassException;
}