com.datastax.oss.driver.api.mapper.annotations.PartitionKey Maven / Gradle / Ivy
/*
* Copyright DataStax, 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.datastax.oss.driver.api.mapper.annotations;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* Annotates the field or getter of an {@link Entity} property, to indicate that it's part of the
* partition key.
*
* Example:
*
*
* @PartitionKey private UUID id;
*
*
* This information is used by the mapper processor to generate default queries (for example a basic
* {@link Select}). Note that an entity is not required to have a partition key, for example if it
* only gets mapped as a UDT.
*
* If the partition key is composite, you must specify {@link #value()} to indicate the position
* of each property:
*
*
* @PartitionKey(1) private int pk1;
* @PartitionKey(2) private int pk2;
*
*
* If you don't specify positions, or if there are duplicates, the mapper processor will issue a
* compile-time error.
*
* This annotation is mutually exclusive with {@link ClusteringColumn}.
*/
@Target({ElementType.FIELD, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface PartitionKey {
/**
* The position of the property in the partition key.
*
*
This is only required if the partition key is composite. Positions are not strictly required
* to be consecutive or start at a given index, but for clarity it is recommended to use
* consecutive integers.
*/
int value() default 0;
}