Kepler Schema dependency

<?xml version="1.0" encoding="UTF-8"?>
<schema
    targetNamespace="http://www.eclipse.org/kepler/project/model/dependency"
    elementFormDefault="qualified"
    xmlns="http://www.w3.org/2001/XMLSchema"
    xmlns:tns="http://www.eclipse.org/kepler/project/model/dependency"
    xmlns:pref="http://www.eclipse.org/kepler/project/model">

    <import namespace="http://www.eclipse.org/kepler/project/model"
        schemaLocation="project-core.xsd">
    </import>

    <complexType name="projectDependency" abstract="true">
        <complexContent>
            <extension base="pref:dependency">
                <sequence>
                    <element name="projectId" type="string"
                        maxOccurs="1" minOccurs="1">
                    </element>
                    <element name="versionId" type="string"
                        maxOccurs="1" minOccurs="0">
                    </element>
                </sequence>
            </extension>
        </complexContent>
    </complexType>

    <complexType name="compileDependency">
        <complexContent>
            <extension base="tns:projectDependency"></extension>
        </complexContent>
    </complexType>

    <complexType name="runtimeDependency">
        <complexContent>
            <extension base="tns:projectDependency"></extension>
        </complexContent>
    </complexType>

    <complexType name="testDependency">
        <complexContent>
            <extension base="tns:projectDependency"></extension>
        </complexContent>
    </complexType>
</schema>