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Chapter 30. Basic Data Binding Concepts

Abstract

There are a number of general topics that apply to how Apache CXF handles type mapping.

30.1. Including and Importing Schema Definitions

Overview

Apache CXF supports the including and importing of schema definitions, using the include and import schema tags. These tags enable you to insert definitions from external files or resources into the scope of a schema element. The essential difference between including and importing is:
  • Including brings in definitions that belong to the same target namespace as the enclosing schema element.
  • Importing brings in definitions that belong to a different target namespace from the enclosing schema element.

xsd:include syntax

The include directive has the following syntax: 
<include schemaLocation="anyURI" />
The referenced schema, given by anyURI, must either belong to the same target namespace as the enclosing schema, or not belong to any target namespace at all. If the referenced schema does not belong to any target namespace, it is automatically adopted into the enclosing schema’s namespace when it is included.
Example 30.1, “Example of a Schema that Includes Another Schema” shows an example of an XML Schema document that includes another XML Schema document.

Example 30.1. Example of a Schema that Includes Another Schema

<definitions targetNamespace="http://schemas.redhat.com/tests/schema_parser"
             xmlns:tns="http://schemas.redhat.com/tests/schema_parser"
             xmlns:xsd="http://www.w3.org/2001/XMLSchema"
             xmlns="http://schemas.xmlsoap.org/wsdl/">
  <types>
    <schema targetNamespace="http://schemas.redhat.com/tests/schema_parser"
            xmlns="http://www.w3.org/2001/XMLSchema">
      <include schemaLocation="included.xsd"/>
      <complexType name="IncludingSequence">
        <sequence>
          <element name="includedSeq" type="tns:IncludedSequence"/>
        </sequence>
      </complexType>
    </schema>
  </types>
  ...
</definitions>
Example 30.2, “Example of an Included Schema” shows the contents of the included schema file.

Example 30.2. Example of an Included Schema

<schema targetNamespace="http://schemas.redhat.com/tests/schema_parser"
        xmlns="http://www.w3.org/2001/XMLSchema">
  <!-- Included type definitions -->
  <complexType name="IncludedSequence">
    <sequence>
      <element name="varInt" type="int"/>
      <element name="varString" type="string"/>
    </sequence>
  </complexType>
</schema>

xsd:import syntax

The import directive has the following syntax: 
<import namespace="namespaceAnyURI"
        schemaLocation="schemaAnyURI" />
The imported definitions must belong to the namespaceAnyURI target namespace. If namespaceAnyURI is blank or remains unspecified, the imported schema definitions are unqualified.
Example 30.3, “Example of a Schema that Imports Another Schema” shows an example of an XML Schema that imports another XML Schema.

Example 30.3. Example of a Schema that Imports Another Schema

<definitions targetNamespace="http://schemas.redhat.com/tests/schema_parser"
             xmlns:tns="http://schemas.redhat.com/tests/schema_parser"
             xmlns:imp="http://schemas.redhat.com/tests/imported_types"
             xmlns:xsd="http://www.w3.org/2001/XMLSchema"
             xmlns="http://schemas.xmlsoap.org/wsdl/">
  <types>
    <schema targetNamespace="http://schemas.redhat.com/tests/schema_parser"
            xmlns="http://www.w3.org/2001/XMLSchema">
      <import namespace="http://schemas.redhat.com/tests/imported_types"
              schemaLocation="included.xsd"/>
      <complexType name="IncludingSequence">
        <sequence>
          <element name="includedSeq" type="imp:IncludedSequence"/>
        </sequence>
      </complexType>
    </schema>
  </types>
  ...
</definitions>
Example 30.4, “Example of an Imported Schema” shows the contents of the imported schema file.

Example 30.4. Example of an Imported Schema

<schema targetNamespace="http://schemas.redhat.com/tests/imported_types"
        xmlns="http://www.w3.org/2001/XMLSchema">
  <!-- Included type definitions -->
  <complexType name="IncludedSequence">
    <sequence>
      <element name="varInt" type="int"/>
      <element name="varString" type="string"/>
    </sequence>
  </complexType>
</schema>

Using non-referenced schema documents

Using types defined in a schema document that is not referenced in the service's WSDL document is a three step process:
  1. Convert the schema document to a WSDL document using the xsd2wsdl tool.
  2. Generate Java for the types using the wsdl2java tool on the generated WSDL document.
    Important
    You will get a warning from the wsdl2java tool stating that the WSDL document does not define any services. You can ignore this warning.
  3. Add the generated classes to your classpath.