maven-obr-plugin/src/main/resources/SchemaObr.xsd

<?xml version="1.0" encoding="ISO-8859-1" ?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
<!-- definition of simple elements -->

<!-- definition of attribute  -->
<xs:attribute name="name"     type="xs:string"/>
<xs:attribute name="filter"   type="xs:string"/>
<xs:attribute name="extend"   type="xs:boolean"/>
<xs:attribute name="multiple" type="xs:boolean"/>
<xs:attribute name="optional" type="xs:boolean"/>
<xs:attribute name="id" type="xs:string"/>
<xs:attribute name="n" type="xs:string"/>
<xs:attribute name="v" type="xs:string"/>
<xs:attribute name="t" type="xs:string"/>

<xs:element name="require">
  <xs:complexType mixed="true">
    <xs:attribute ref="name"     use="required"/>
    <xs:attribute ref="filter"   use="required"/>
    <xs:attribute ref="extend"   use="required"/>
    <xs:attribute ref="multiple" use="required"/>
    <xs:attribute ref="optional" use="required"/>
  </xs:complexType>
</xs:element>

<xs:element name="category">
  <xs:complexType>
	<xs:attribute ref="id" use="required"/>
  </xs:complexType>
</xs:element>

<xs:element name="p">
  <xs:complexType>
	<xs:attribute ref="n" use="required"/>
    <xs:attribute ref="v" use="required"/>
    <xs:attribute ref="t" />
  </xs:complexType>
</xs:element>


<xs:element name="capability">
  <xs:complexType>
    <xs:sequence>
  		<xs:element ref="p" minOccurs="0" maxOccurs="unbounded"/>
	</xs:sequence>
  </xs:complexType>
</xs:element>

<xs:element name="resource">
  <xs:complexType>
    <xs:sequence>
		  <xs:element ref="capability" minOccurs="0" maxOccurs="unbounded"/> 
		  <xs:element ref="require" minOccurs="0" maxOccurs="unbounded"/> 
		  <xs:element ref="category" minOccurs="0" maxOccurs="unbounded"/> 
	</xs:sequence>
  </xs:complexType>
</xs:element>
</xs:schema>