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Revision as of 10:16, 23 May 2011
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Key API
Keys and Foreign Keys
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
In 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
Because this example requires support beyond the JAXB specification, you can use the EclipseLink extension @XmlKey. Because the relationship is bidirectional, 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
Because the target object has a compound key, use the EclipseLink extension @XmlJoinNodes to set up the mapping.
Note: If the target object had a single ID, then you could use @XmlIDREF.
@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; }
