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Difference between revisions of "EclipseLink/Examples/MOXy/JPA/CompoundPrimaryKeys"
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=== Target Object === | === Target Object === | ||
| − | As we require support beyond the JAXB spec, we will make use the EclipseLink | + | As we require support beyond the JAXB spec, we will make use of the EclipseLink extensions @XmlKey and @XmlJoinNodes. Also since the relationship is bidirectional, we will use the EclipseLink extension @XmlInverseReference. |
<source lang="java"> | <source lang="java"> | ||
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@Id | @Id | ||
@Column(name="E_ID") | @Column(name="E_ID") | ||
| + | @XmlID | ||
private BigDecimal eId; | private BigDecimal eId; | ||
@Id | @Id | ||
| + | @XmlKey | ||
private String country; | private String country; | ||
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@XmlInverseReference(mappedBy="contact") | @XmlInverseReference(mappedBy="contact") | ||
private List<PhoneNumber> contactNumber; | private List<PhoneNumber> contactNumber; | ||
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Revision as of 16:29, 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 extensions @XmlKey and @XmlJoinNodes. Also since the relationship is bidirectional, we will use the EclipseLink extension @XmlInverseReference.
@Entity @IdClass(EmployeeId.class) @XmlCustomizer(EmployeeCustomizer.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 mark the field @XmlTransient, and use the EclipseLink extension @XmlCustomizer to set up the mapping.
@Entity @XmlCustomizer(PhoneNumberCustomizer.class) public class PhoneNumber { @ManyToOne @JoinColumns({ @JoinColumn(name="E_ID", referencedColumnName = "E_ID"), @JoinColumn(name="E_COUNTRY", referencedColumnName = "COUNTRY") }) @XmlTransient private Employee contact; }
An XMLObjectReferenceMapping will be created. The mapping will include multiple key mappings.
import org.eclipse.persistence.config.DescriptorCustomizer; import org.eclipse.persistence.descriptors.ClassDescriptor; import org.eclipse.persistence.oxm.mappings.XMLObjectReferenceMapping; public class PhoneNumberCustomizer implements DescriptorCustomizer { public void customize(ClassDescriptor descriptor) throws Exception { XMLObjectReferenceMapping contactMapping = new XMLObjectReferenceMapping(); contactMapping.setAttributeName("contact"); contactMapping.setReferenceClass(Employee.class); contactMapping.addSourceToTargetKeyFieldAssociation("contact/@eID", "eId/text()"); contactMapping.addSourceToTargetKeyFieldAssociation("contact/@country", "country/text()"); descriptor.addMapping(contactMapping); } }