| // Copyright 2009 Google Inc. |
| // |
| // 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 com.google.gwtorm.server; |
| |
| /** |
| * Atomically updates exactly one entity. |
| */ |
| public interface AtomicUpdate<T> { |
| /** |
| * Update the one object, in place. |
| * <p> |
| * This method may be called multiple times, up until the retry limit. |
| * |
| * @param row a fresh copy of the object. The updater should modify it in |
| * place and return, the caller will attempt to rewrite it into the |
| * database. |
| * @return return value for the application code calling the atomic update; |
| * should be either {@code instance} or {@code null}. |
| */ |
| T update(T row); |
| } |