/*
* 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 http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
* Linda DeMichiel - Java Persistence 2.0 - Version 2.0 (October 1, 2009)
* Specification available from http://jcp.org/en/jsr/detail?id=317
*/
// $Id: AttributeOverride.java 20957 2011-06-13 09:58:51Z stliu $
package javax.persistence;
import java.lang.annotation.Target;
import java.lang.annotation.Retention;
import static java.lang.annotation.ElementType.TYPE;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
/**
* Used to override the mapping of a <code>Basic</code> (whether
* explicit or default) property or field or <code>Id</code> property or
* field.
*
* <p> May be applied to an entity that extends a mapped superclass or
* to an embedded field or property to override a basic mapping or id
* mapping defined by the mapped superclass or embeddable class (or
* embeddable class of one of its attributes).
* <p> May be applied to an element collection containing instances of
* an embeddable class or to a map collection whose key and/or value
* is an embeddable class. When <code>AttributeOverride</code> is
* applied to a map, "<code>key.</code>" or "<code>value.</code>" must
* be used to prefix the name of the attribute that is being
* overridden in order to specify it as part of the map key or map
* value.
*
* <p> To override mappings at multiple levels of embedding, a dot (".")
* notation form must be used in the <code>name</code> element to indicate an
* attribute within an embedded attribute. The value of each identifier
* used with the dot notation is the name of the respective embedded
* field or property.
*
* <p> If <code>AttributeOverride</code> is not specified, the column
* is mapped the same as in the original mapping.
*
* <pre>
* Example 1:
*
* @MappedSuperclass
* public class Employee {
* @Id protected Integer id;
* @Version protected Integer version;
* protected String address;
* public Integer getId() { ... }
* public void setId(Integer id) { ... }
* public String getAddress() { ... }
* public void setAddress(String address) { ... }
* }
*
* @Entity
* @AttributeOverride(name="address", column=@Column(name="ADDR"))
* public class PartTimeEmployee extends Employee {
* // address field mapping overridden to ADDR
* protected Float wage();
* public Float getHourlyWage() { ... }
* public void setHourlyWage(Float wage) { ... }
* }
*
*
* Example 2:
*
* @Embeddable public class Address {
* protected String street;
* protected String city;
* protected String state;
* @Embedded protected Zipcode zipcode;
* }
*
* @Embeddable public class Zipcode {
* protected String zip;
* protected String plusFour;
* }
*
* @Entity public class Customer {
* @Id protected Integer id;
* protected String name;
* @AttributeOverrides({
* @AttributeOverride(name="state",
* column=@Column(name="ADDR_STATE")),
* @AttributeOverride(name="zipcode.zip",
* column=@Column(name="ADDR_ZIP"))
* })
* @Embedded protected Address address;
* ...
* }
*
*
* Example 3:
*
* @Entity public class PropertyRecord {
* @EmbeddedId PropertyOwner owner;
* @AttributeOverrides({
* @AttributeOverride(name="key.street",
* column=@Column(name="STREET_NAME")),
* @AttributeOverride(name="value.size",
* column=@Column(name="SQUARE_FEET")),
* @AttributeOverride(name="value.tax",
* column=@Column(name="ASSESSMENT"))
* })
* @ElementCollection
* Map<Address, PropertyInfo> parcels;
* }
*
* @Embeddable public class PropertyInfo {
* Integer parcelNumber;
* Integer size;
* BigDecimal tax;
* }
*
* </pre>
*
* @see Embedded
* @see Embeddable
* @see MappedSuperclass
* @see AssociationOverride
*
* @since Java Persistence 1.0
*/
@Target({TYPE, METHOD, FIELD})
@Retention(RUNTIME)
public @interface AttributeOverride {
/**
* (Required) The name of the property whose mapping is being
* overridden if property-based access is being used, or the
* name of the field if field-based access is used.
*/
String name();
/**
* (Required) The column that is being mapped to the persistent
* attribute. The mapping type will remain the same as is
* defined in the embeddable class or mapped superclass.
*/
Column column();
}