com.github.helenusdriver.persistence.RootEntity Maven / Gradle / Ivy
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/*
* Copyright (C) 2015-2015 The Helenus Driver Project 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 com.github.helenusdriver.persistence;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* The RootEntity annotation must be used on all classes defining
* a base class for other classes. This is similar to the {@link Entity}
* annotation with the difference that it applies only to an abstract base class
* and all the columns of that class gets persisted to Cassandra. In addition,
* all columns of all defined types are also persisted with the restriction that
* if two different type entities uses the same column name, it must be
* persisted the same way (i.e. same Cassandra type).
*
* All subclasses must be annotated with the {@link TypeEntity} annotation in
* order to indicate the specific type of this base class they represent.
*
* The base class annotated with {@link RootEntity} must include a single column
* as an attribute type {@link String} annotated with the @typeKey annotation.
* This attribute will be used to hold the entity type and used to identify the
* class that will be re-created at the time an object is retrieved from Cassandra.
*
* The root entity class must defined all partition and /or clustering keys and
* must defined the keyspace and all tables.
*
* @copyright 2015-2015 The Helenus Driver Project Authors
*
* @author The Helenus Driver Project Authors
* @version 1 - Jan 15, 2015 - paouelle - Creation
*
* @since 1.0
*/
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface RootEntity {
/**
* List of supported types for this root entity.
*
* @author paouelle
*
* @return the list of supported types
*/
Class[] types();
}