Node.java

package org.hibernate.envers.test.integration.onetomany.hierarchy;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;
import javax.persistence.Table;

import org.hibernate.envers.AuditJoinTable;
import org.hibernate.envers.Audited;

/**
 * @author Lukasz Antoniak (lukasz dot antoniak at gmail dot com)
 */
@Entity
@Table(name = "NODES")
@Audited
public class Node implements Serializable {
    @Id
    @GeneratedValue
    private Long id;

    private String data;

    @ManyToOne(fetch = FetchType.LAZY, optional = true)
    @AuditJoinTable(name = "NODES_JOIN_TABLE_AUD",
                    inverseJoinColumns = {@JoinColumn(name = "PARENT_ID", nullable = true, updatable = false)})
    @JoinTable(name = "NODES_JOIN_TABLE",
               joinColumns = {@JoinColumn(name = "CHILD_ID", nullable = true, updatable = false)},
               inverseJoinColumns = {@JoinColumn(name = "PARENT_ID", nullable = true, updatable = false)})
    private Node parent;

    @OneToMany(mappedBy = "parent")
    private List<Node> children = new ArrayList<Node>();

    public Node() {
    }

    public Node(String data, Node parent) {
        this.data = data;
        this.parent = parent;
    }

    public Node(String data, Long id) {
        this.id = id;
        this.data = data;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof Node)) return false;

        Node node = (Node) o;

        if (data != null ? !data.equals(node.data) : node.data != null) return false;
        if (id != null ? !id.equals(node.id) : node.id != null) return false;

        return true;
    }

    @Override
    public int hashCode() {
        int result = id != null ? id.hashCode() : 0;
        result = 31 * result + (data != null ? data.hashCode() : 0);
        return result;
    }

    @Override
    public String toString() {
        return "Node(id = " + id + ", data = " + data + ")";
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getData() {
        return data;
    }

    public void setData(String data) {
        this.data = data;
    }

    public Node getParent() {
        return parent;
    }

    public void setParent(Node parent) {
        this.parent = parent;
    }

    public List<Node> getChildren() {
        return children;
    }

    public void setChildren(List<Node> children) {
        this.children = children;
    }
}