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   * Copyright (c) 2008, 2009 Sun Microsystems. All rights reserved.
   * This program and the accompanying materials are made available under the
   * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
   * which accompanies this distribution.
   * The Eclipse Public License is available at
   * and the Eclipse Distribution License is available at
  * Contributors:
  *     Linda DeMichiel - Java Persistence 2.0 - Version 2.0 (October 1, 2009)
  *     Specification available from
 // $Id: 20957 2011-06-13 09:58:51Z stliu $
 package javax.persistence;
 import static java.lang.annotation.ElementType.TYPE;
 import static java.lang.annotation.RetentionPolicy.RUNTIME;

Designates a class whose mapping information is applied to the entities that inherit from it. A mapped superclass has no separate table defined for it.

A class designated with the MappedSuperclass annotation can be mapped in the same way as an entity except that the mappings will apply only to its subclasses since no table exists for the mapped superclass itself. When applied to the subclasses the inherited mappings will apply in the context of the subclass tables. Mapping information may be overridden in such subclasses by using the AttributeOverride and AssociationOverride annotations or corresponding XML elements.

    Example: Concrete class as a mapped superclass

    public class Employee {

        @Id protected Integer empId;
        @Version protected Integer version;
        @ManyToOne @JoinColumn(name="ADDR")
        protected Address address;

        public Integer getEmpId() { ... }
        public void setEmpId(Integer id) { ... }
        public Address getAddress() { ... }
        public void setAddress(Address addr) { ... }

    // Default table is FTEMPLOYEE table
    public class FTEmployee extends Employee {

        // Inherited empId field mapped to FTEMPLOYEE.EMPID
        // Inherited version field mapped to FTEMPLOYEE.VERSION
        // Inherited address field mapped to FTEMPLOYEE.ADDR fk

        // Defaults to FTEMPLOYEE.SALARY
        protected Integer salary;

        public FTEmployee() {}

        public Integer getSalary() { ... }

        public void setSalary(Integer salary) { ... }

    @Entity @Table(name="PT_EMP")
    public class PartTimeEmployee extends Employee {

        // Inherited empId field mapped to PT_EMP.EMPID
        // Inherited version field mapped to PT_EMP.VERSION
        // address field mapping overridden to PT_EMP.ADDR_ID fk
        protected Float hourlyWage;

        public PartTimeEmployee() {}

        public Float getHourlyWage() { ... }
        public void setHourlyWage(Float wage) { ... }

Java Persistence 1.0
See also:
public @interface MappedSuperclass {
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