EclipseLink/Examples/MOXy/XMLNameTransformer

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JAXB has well established rules for converting Java names to XML names which can be overridden through the use of annotations. Where this can become burdensome is if your names follow common rules (such as make everything upper case). As of EclipseLink 2.3 a new MOXy JAXB feature exists to allow you to override the default naming algorithm.

This example will create an implementation of org.eclipse.persistence.oxm.XMLNameTransformer to provide a naming algorithm to MOXy.

Contents

XMLNameTransformer Implementation

package examples;
public class NameMangler implements org.eclipse.persistence.oxm.XMLNameTransformer {
 
    //Use the unqualified class name as our root element name.
    public String transformRootElementName(String name) {
        return name.substring(name.lastIndexOf('.') + 1);
    }
 
    //The same algorithm as root element name plus "Type" appended to the end.
    public String transformTypeName(String name) {
        return transformRootElementName(name) + "Type";
    }
 
    //The name will be lower case with word breaks represented by '-'.  
    //Note:  A capital letter in the original name represents the start of a new word.
    public String transformElementName(String name) {
        StringBuilder strBldr = new StringBuilder();
        for(char character : name.toCharArray()) {
            if(Character.isUpperCase(character)) {
                strBldr.append('-');
                strBldr.append(Character.toLowerCase(character));
            } else {
                strBldr.append(character);
            }
         }
        return strBldr.toString();
    }
 
    //The original name converted to upper case.
    public String transformAttributeName(String name) {
        return name.toUpperCase();
    }
 
}

Java Model

The following domain model will be used. To save space the accessors have been omitted.

Customer.java

import javax.xml.bind.annotation.*;
 
@XmlRootElement
@XmlType(propOrder={"fullName", "shippingAddress"})
@XmlAccessorType(XmlAccessType.FIELD)
public class Customer {
 
    @XmlAttribute
    private long id;
 
    private String fullName;     
 
    private Address shippingAddress;
}

Address.java

import javax.xml.bind.annotation.*;
 
@XmlAccessorType(XmlAccessType.FIELD)
public class Address {
 
    @XmlAttribute
    private String type;
 
    private String street;
 
}

XML output using JAXB's default naming algorithm

Using JAXB's default naming algorithm our object model will be converted to XML that looks like the following:

<?xml version="1.0" encoding="UTF-8"?>
<customer id="123">
    <fullName>Jane Doe</fullName>
    <shippingAddress type="residential">
        <street>1 Any Street</street>
    </shippingAddress>
</customer>

Specifying the naming algorithm

Our implementation of the naming algorithm can be provided via the @XmlNameTransformer annotation (package or type level) or via the external bindings file in XML 1. At the type level

@XmlNameTransformer(examples.NameMangler.class)
public class Customer

2. At the package level (package-info.java)

@XmlNameTransformer(examples.NameMangler.class)
package examples;

3. External bindings file

<?xml version='1.0' encoding='UTF-8'?>
<xml-bindings xmlns='http://www.eclipse.org/eclipselink/xsds/persistence/oxm' xml-name-transformer='examples.NameMangler'>
<xml-schema/>
<java-types/>
</xml-bindings>

For more information on how to use and specify a bindings file see the EclipseLink-OXM.XML example

XML output using specified XMLNameTransformer

By leveraging our customized naming algorithm we can get the following output without specifying any additional metadata on our domain classes:

<?xml version="1.0" encoding="UTF-8"?>
<Customer ID="123">
   <full-name>Jane Doe</full-name>
   <shipping-address TYPE="residential">
      <street>1 Any Street</street>
   </shipping-address>
</Customer>

Equivalent JAXB metadata

Without overriding the naming algorithm, we would have had to specify additional JAXB metadata to get the desired XML output: Customer.java

import  javax.xml.bind.annotation.*;
 
@XmlRootElement(name="Customer")
@XmlType(
        name="CustomerType",
        propOrder={"fullName", "shippingAddress"})
@XmlAccessorType(XmlAccessType.FIELD)
public class Customer {
 
    @XmlAttribute(name="ID")
    private long id;
 
    @XmlElement(name="full-name")
    private String fullName;
 
    @XmlElement(name="shipping-address")
    private Address shippingAddress;
 
}

Address.java

import javax.xml.bind.annotation.*;
 
@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name="AddressType")
public class Address {
 
    @XmlAttribute(name="TYPE")
    private String type;
 
    private String street;
 
}