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Difference between revisions of "EclipseLink/Examples/MOXy/JPA/CompoundPrimaryKeys"

< EclipseLink‎ | Examples‎ | MOXy‎ | JPA
(Target Object)
 
(One intermediate revision by the same user not shown)
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=== Source Object ===
 
=== 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.
+
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">
 
<source lang="java">
 
@Entity
 
@Entity
@XmlCustomizer(PhoneNumberCustomizer.class)
 
 
public class PhoneNumber {
 
public class PhoneNumber {
  
Line 98: Line 97:
 
         @JoinColumn(name="E_COUNTRY", referencedColumnName = "COUNTRY")
 
         @JoinColumn(name="E_COUNTRY", referencedColumnName = "COUNTRY")
 
     })
 
     })
     @XmlTransient
+
     @XmlJoinNodes( {
 +
        @XmlJoinNode(xmlPath="contact/id/text()", referencedXmlPath="id/text()"),
 +
        @XmlJoinNode(xmlPath="contact/country/text()", referencedXmlPath="country/text()")
 +
    })
 
     private Employee contact;
 
     private Employee contact;
 
}
 
</source>
 
 
An XMLObjectReferenceMapping will be created.  The mapping will include multiple key mappings.
 
 
<source lang="java">
 
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);
 
    }
 
  
 
}
 
}
 
</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;
 
}