EclipseLink/Examples/MOXy/JPA/EmbeddedIdClass

Overview

This example demonstrates how to derive an XML representation from a set of JPA entities using JAXB when a JPA entity has an embedded ID class.

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 {
 
    @EmbeddedId
    private EmployeeId id;
 
    @OneToMany(mappedBy="contact")
    private List<PhoneNumber> contactNumber;
 
}

@Embeddable
public class EmployeeId {
 
    @Column(name="E_ID")
    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

@Entity
@IdClass(EmployeeId.class)
@XmlCustomizer(EmployeeCustomizer.class)
public class Employee {
 
    @EmbeddedId
    private EmployeeId id;
 
    @OneToMany(mappedBy="contact")
    @XmlInverseReference(mappedBy="contact")
    private List<PhoneNumber> contactNumber;
 
}

import org.eclipse.persistence.config.DescriptorCustomizer;
import org.eclipse.persistence.descriptors.ClassDescriptor;
import org.eclipse.persistence.oxm.mappings.XMLCompositeObjectMapping;
 
public class EmployeeCustomizer implements DescriptorCustomizer {
 
    public void customize(ClassDescriptor descriptor) throws Exception {
        XMLCompositeObjectMapping idMapping = (XMLCompositeObjectMapping) descriptor.getMappingForAttributeName("id");
        idMapping.setXPath(".");
 
        descriptor.addPrimaryKeyFieldName("eId/text()");
        descriptor.addPrimaryKeyFieldName("country/text()");
    }
 
}

Source Object

@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;
 
}

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);
    }
 
}