com.datastax.oss.driver.api.mapper.annotations.SchemaHint Maven / Gradle / Ivy

Go to download
/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.datastax.oss.driver.api.mapper.annotations;

import com.datastax.oss.driver.api.mapper.MapperBuilder;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * Annotates an entity to indicate which type of schema element it is supposed to map to. This is
 * only used to optimize {@linkplain MapperBuilder#withSchemaValidationEnabled(boolean) schema
 * validation}, it has no impact on query execution.
 *
 * Example:
 *
 * 
 * @Entity
 * @SchemaHint(targetElement = SchemaHint.TargetElement.TABLE)
 * public class Product {
 *   // fields of the entity
 * }
 * 
 *
 * By default, the mapper first tries to match the entity with a table, and if that doesn't work,
 * with a UDT. This annotation allows you to provide a hint as to which check should be done, so
 * that the mapper can skip the other one.
 *
 * In addition, you can ask to completely skip the validation for this entity by using {@link
 * TargetElement#NONE}.
 */
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface SchemaHint {
  TargetElement targetElement();

  enum TargetElement {
    TABLE,
    UDT,
    NONE,
    ;
  }
}