/* * Copyright 2006 Amazon Technologies, Inc. or its affiliates. * Amazon, Amazon.com and Carbonado are trademarks or registered trademarks * of Amazon Technologies, Inc. or its affiliates. All rights reserved. * * 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.amazon.carbonado; import java.lang.annotation.*; /** * A hint for a dependent {@link Repository} to allow a {@link Storable} property or type * to be undefined in the underlying schema. Ordinarily, if a dependent repository cannot * find a matching property, it throws {@link MismatchException} when the {@link Storage} is * first retrieved for the storable. This annotation suppresses that exception, and instead * makes the property or type unsupported. Any subsequent invocation of a property access * method for the independent type or property will cause an UnsupportedOperationException * to be thrown. *

* One example of when this might be used would be to store a calculated field in the cached * representation of the object. It is not necessary to prevent implemented methods * of the form "get<value>" from being inadvertently interpreted as properties of the * storable; any implementation is by definition not a property. *

* If a correctly matching property actually is found, then this annotation is * ignored and the property or type is defined as usual. If the Repository * finds a property whose name matches, but whose type does not match, a * MismatchException will be thrown regardless of this annotation. * *

Independent repositories completely ignore this annotation. * *

Example:

 * public interface UserInfo extends Storable<UserInfo> {
 *     @Independent
 *     String getName();
 *
 *     ...
 * }
 *
* * Note: If a {@link Version versioned} Storable with an independent * property is managed by a replicating repository, updates which modify just * the independent property still update the master Storable, in order to get a * new record version. Therefore, independent properties should not be used as * a performance enhancement which avoids writes to a master repository. * * @author Brian S O'Neill */ @Documented @Retention(RetentionPolicy.RUNTIME) @Target({ElementType.TYPE, ElementType.METHOD}) public @interface Independent { }