JAXB require boolean

Question

I am trying to generate a XSD file with a boolean element that is always required. When I use the XSD file to generate the java classes (with JAXB) the field is not required.

I have attempted the following versions:

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
           xmlns:tns="http://com.my.example/test"
           targetNamespace="http://com.my.example/test"
           elementFormDefault="qualified">
    <xs:complexType name="MyComplexElement">
        <xs:sequence>
            <xs:element name="MySimpleElement" type="xs:boolean" minOccurs="1" maxOccurs="1" nillable="false"/>
            <xs:element name="MySimpleElement2" type="xs:boolean" minOccurs="1" maxOccurs="1" nillable="true"/>
        </xs:sequence>
    </xs:complexType>
</xs:schema>

That XSD file generates me the following fields in the Java class:

    @XmlElement(name = "MySimpleElement")
    protected boolean mySimpleElement;
    @XmlElement(name = "MySimpleElement2", required = true, type = Boolean.class, nillable = true)
    protected Boolean mySimpleElement2;

Whereas I was expecting something like this:

    @XmlElement(name = "MySimpleElement", required=true) // This one would be my preferred one
    protected boolean mySimpleElement;
    @XmlElement(name = "MySimpleElement2", required = true, type = Boolean.class, nillable = false)
    protected Boolean mySimpleElement2;

I also have attempted to generate the XSD file from a java class but I wasn't able to do it either.

Note: I am using org.codehaus.mojo.jaxb2-maven-plugin version:2.5.0

Answer 1

An xml element of type xs:boolean which is not nillable can be represented in java by primitive data type boolean because a boolean always has a value (true or false) - it cannot be null. Because it always has a value, it is not needed to specifically mark it as required to have the xml element generated.

An xml element of type xs:boolean which is nillable cannot be represented by primitive data type boolean because a boolean cannot be null. Therefore it is represented by a Boolean object. Because it can be null, it is needed to specifically mark it as required to have the xml element generated even if it is null.