<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
           xmlns:example="http://www.example.org/root"
           xmlns="http://www.example.org/root"
           targetNamespace="http://www.example.org/root"
           elementFormDefault="qualified" attributeFormDefault="unqualified">
    <xs:element name="Root">
        <xs:complexType>
            <xs:choice maxOccurs="unbounded">
                <xs:element ref="Object" />
            </xs:choice>
        </xs:complexType>
        <xs:key name="name_key">
            <xs:selector xpath=".//example:Object" />
            <xs:field xpath="@name" />
        </xs:key>
        <xs:keyref name="Collectiontype_defined" refer="name_key">
            <xs:selector xpath=".//example:CollectionMember" />
            <xs:field xpath="@type" />
        </xs:keyref>
    </xs:element>
    <xs:element name="Members">
        <xs:complexType>
            <xs:group ref="example:memberTypes" minOccurs="0"
                      maxOccurs="unbounded" />
        </xs:complexType>
    </xs:element>
    <xs:element name="Object">
        <xs:complexType>
            <xs:sequence>
                <xs:element ref="Members" minOccurs="0" />
            </xs:sequence>
            <xs:attributeGroup ref="example:typedMemberAttributes" />
            <xs:attributeGroup ref="example:namedMemberAttributes" />
        </xs:complexType>
        <xs:unique name="ObjectElementNameUniqueness">
            <xs:selector xpath="example:Members/*" />
            <xs:field xpath="@name" />
        </xs:unique>
    </xs:element>
    <xs:element name="Collection">
        <xs:complexType>
            <xs:sequence>
                <xs:element ref="CollectionMembers" />
            </xs:sequence>
            <xs:attributeGroup ref="example:namedMemberAttributes" />
        </xs:complexType>
    </xs:element>
    <xs:element name="CollectionMembers">
        <xs:complexType>
            <xs:sequence>
                <xs:element ref="CollectionMember" minOccurs="2"
                            maxOccurs="unbounded" />
            </xs:sequence>
        </xs:complexType>
    </xs:element>
    <xs:element name="CollectionMember">
        <xs:complexType>
            <xs:sequence>
                <xs:element ref="Members" minOccurs="0"
                            maxOccurs="unbounded" />
            </xs:sequence>
            <xs:attributeGroup ref="example:typedMemberAttributes" />
            <xs:attributeGroup ref="example:namedMemberAttributes" />
        </xs:complexType>
    </xs:element>
    <xs:element name="String">
        <xs:complexType>
            <xs:attributeGroup ref="example:namedMemberAttributes" />
        </xs:complexType>
    </xs:element>
    <xs:group name="memberTypes">
        <xs:choice>
            <xs:element ref="String" />
            <xs:element ref="Collection" />
        </xs:choice>
    </xs:group>
    <xs:attributeGroup name="namedMemberAttributes">
        <xs:attribute name="name" type="xs:Name" use="required" />
    </xs:attributeGroup>
    <xs:attributeGroup name="typedMemberAttributes">
        <xs:attribute name="type" type="xs:Name" />
    </xs:attributeGroup>
</xs:schema>