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

@Entity
public class Parent {

	@Id
	@GeneratedValue
	Long id;

	static final long serialVersionUID = -89717120680485957L;

	@ManyToMany(cascade = CascadeType.ALL)
	Set<Child> children = new HashSet<Child>();

	public Parent add(Child child) {

		this.children.add(child);

		if (!child.parents.contains(this)) {
			child.add(this);
		}

		return this;
	}
}