Child.java

/*
 * Copyright 2013 the original author or 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 org.springframework.data.jpa.domain.sample;

import java.util.HashSet;
import java.util.Set;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.ManyToMany;

@Entity
public class Child {

	@Id
	@GeneratedValue
	Long id;

	@ManyToMany(mappedBy = "children")
	Set<Parent> parents = new HashSet<Parent>();

	/**
	 * @param parent
	 */
	public Child add(Parent parent) {

		this.parents.add(parent);

		if (!parent.children.contains(this)) {
			parent.add(this);
		}

		return this;
	}
}