com.getperka.flatpack.SparseCollection Maven / Gradle / Ivy
package com.getperka.flatpack;
/*
* #%L
* FlatPack serialization code
* %%
* Copyright (C) 2012 Perka 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.
* #L%
*/
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;
/**
* Applied to a collection property getter to indicate that the collection should not be traversed
* in {@link TraversalMode#SIMPLE}. Additionally, this annotation may name a property in the
* collection's element type that will cause FlatPack to keep two sides of a relationship in sync if
* an incoming payload only specifies one of the relationships.
*
* Consider the following example:
*
*
* class Child extends BaseHasUuid {
* public Parent getParent() {}
* }
* class Parent extends BaseHasUuid {
* {@literal @SparseCollection("parent")}
* public List getChildren();
* }
*
*
* If the following payload is received
*
*
* {
* "value" : "abc-123",
* "data" : {
* "child" : [
* {
* "uuid" : "abc-123",
* "parent" : "987-fed"
* ]
* ]
* }
* }
*
*
* then if a {@code Parent} with uuid {@code 987-fed} is resolved, the incoming {@code Child} will
* be added automatically to the {@code Parent.children} collection. Conversely, if a {@code Parent}
* is received that referances a {@code Child}, whether in the payload or resolved from a backing
* store, the {@code Child.parent} property will be implicitly updated.
*
* This annotation is interchangeable with JPA's {@code @OneToMany} annotation with an explicit
* {@code mappedBy} property.
*/
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface SparseCollection {
/**
* The name of the property in the referenced entity type to update.
*/
String value() default "";
}