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Difference between revisions of "EclipseLink/Examples/MOXy/JPA/CompoundPrimaryKeys"
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== Overview == | == Overview == | ||
| + | |||
| + | This example demonstrates how to derive an XML representation from a set of JPA entities using JAXB when a JPA entity has compound primary keys. | ||
== JPA Entities == | == JPA Entities == | ||
| Line 12: | Line 14: | ||
@JoinColumn(name="E_COUNTRY", referencedColumnName = "COUNTRY") | @JoinColumn(name="E_COUNTRY", referencedColumnName = "COUNTRY") | ||
}) | }) | ||
| − | + | ||
private Employee contact; | private Employee contact; | ||
| Line 25: | Line 27: | ||
@Id | @Id | ||
@Column(name="E_ID") | @Column(name="E_ID") | ||
| − | |||
private BigDecimal eId; | private BigDecimal eId; | ||
@Id | @Id | ||
| − | |||
private String country; | private String country; | ||
@OneToMany(mappedBy="contact") | @OneToMany(mappedBy="contact") | ||
| − | |||
private List<PhoneNumber> contactNumber; | private List<PhoneNumber> contactNumber; | ||
| Line 58: | Line 57: | ||
import javax.xml.bind.annotation.XmlAccessType; | import javax.xml.bind.annotation.XmlAccessType; | ||
import javax.xml.bind.annotation.XmlAccessorType; | import javax.xml.bind.annotation.XmlAccessorType; | ||
| + | </source> | ||
| + | |||
| + | === Target Object === | ||
| + | |||
| + | As we require support beyond the JAXB spec, we will make use of the EclipseLink extension @XmlKey. Also since the relationship is bidirectional, we will use the EclipseLink extension @XmlInverseReference. | ||
| + | |||
| + | <source lang="java"> | ||
| + | @Entity | ||
| + | @IdClass(EmployeeId.class) | ||
| + | public class Employee { | ||
| + | |||
| + | @Id | ||
| + | @Column(name="E_ID") | ||
| + | @XmlID | ||
| + | private BigDecimal eId; | ||
| + | |||
| + | @Id | ||
| + | @XmlKey | ||
| + | private String country; | ||
| + | |||
| + | @OneToMany(mappedBy="contact") | ||
| + | @XmlInverseReference(mappedBy="contact") | ||
| + | private List<PhoneNumber> contactNumber; | ||
| + | |||
| + | } | ||
| + | </source> | ||
| + | |||
| + | === Source Object === | ||
| + | |||
| + | If the target object had a single ID then we would use @XmlIDREF. Since the target object has a compound key, we will use the EclipseLink extension @XmlJoinNodes to set up the mapping. | ||
| + | |||
| + | <source lang="java"> | ||
| + | @Entity | ||
| + | public class PhoneNumber { | ||
| + | |||
| + | @ManyToOne | ||
| + | @JoinColumns({ | ||
| + | @JoinColumn(name="E_ID", referencedColumnName = "E_ID"), | ||
| + | @JoinColumn(name="E_COUNTRY", referencedColumnName = "COUNTRY") | ||
| + | }) | ||
| + | @XmlJoinNodes( { | ||
| + | @XmlJoinNode(xmlPath="contact/id/text()", referencedXmlPath="id/text()"), | ||
| + | @XmlJoinNode(xmlPath="contact/country/text()", referencedXmlPath="country/text()") | ||
| + | }) | ||
| + | private Employee contact; | ||
| + | |||
| + | } | ||
</source> | </source> | ||
Latest revision as of 16:34, 16 March 2011
Overview
This example demonstrates how to derive an XML representation from a set of JPA entities using JAXB when a JPA entity has compound primary keys.
JPA Entities
@Entity public class PhoneNumber { @ManyToOne @JoinColumns({ @JoinColumn(name="E_ID", referencedColumnName = "E_ID"), @JoinColumn(name="E_COUNTRY", referencedColumnName = "COUNTRY") }) private Employee contact; }
@Entity @IdClass(EmployeeId.class) public class Employee { @Id @Column(name="E_ID") private BigDecimal eId; @Id private String country; @OneToMany(mappedBy="contact") private List<PhoneNumber> contactNumber; }
public class EmployeeId { private BigDecimal eId; private String country; }
JAXB Bindings
For this example the XML acessor type will be set to FIELD for all the model classes. This can be set as a package level JAXB annotation.
@XmlAccessorType(XmlAccessType.FIELD) package com.example.model; import javax.xml.bind.annotation.XmlAccessType; import javax.xml.bind.annotation.XmlAccessorType;
Target Object
As we require support beyond the JAXB spec, we will make use of the EclipseLink extension @XmlKey. Also since the relationship is bidirectional, we will use the EclipseLink extension @XmlInverseReference.
@Entity @IdClass(EmployeeId.class) public class Employee { @Id @Column(name="E_ID") @XmlID private BigDecimal eId; @Id @XmlKey private String country; @OneToMany(mappedBy="contact") @XmlInverseReference(mappedBy="contact") private List<PhoneNumber> contactNumber; }
Source Object
If the target object had a single ID then we would use @XmlIDREF. Since the target object has a compound key, we will use the EclipseLink extension @XmlJoinNodes to set up the mapping.
@Entity public class PhoneNumber { @ManyToOne @JoinColumns({ @JoinColumn(name="E_ID", referencedColumnName = "E_ID"), @JoinColumn(name="E_COUNTRY", referencedColumnName = "COUNTRY") }) @XmlJoinNodes( { @XmlJoinNode(xmlPath="contact/id/text()", referencedXmlPath="id/text()"), @XmlJoinNode(xmlPath="contact/country/text()", referencedXmlPath="country/text()") }) private Employee contact; }