Fuse ESB - Writing WSDL Contracts

Defining arrays

Fuse Services Framework supports two methods for defining arrays in a contract. The first is define a complex type with a single element whose maxOccurs attribute has a value greater than one. The second is to use SOAP arrays. SOAP arrays provide added functionality such as the ability to easily define multi-dimensional arrays and to transmit sparsely populated arrays.

Complex type arrays

Complex type arrays are a special case of a sequence complex type. You simply define a complex type with a single element and specify a value for the maxOccurs attribute. For example, to define an array of twenty floating point numbers you use a complex type similar to the one shown in Example 9.

Example 9. Complex type array

<complexType name="personalInfo">
  <element name="averages" type="xsd:float" maxOccurs="20"/>
</complexType>

You can also specify a value for the minOccurs attribute.

SOAP arrays

SOAP arrays are defined by deriving from the SOAP-ENC:Array base type using the wsdl:arrayType element. The syntax for this is shown in Example 10.

Example 10. Syntax for a SOAP array derived using wsdl:arrayType

<complexType name="TypeName">
  <complexContent>
    <restriction base="SOAP-ENC:Array">
      <attribute ref="SOAP-ENC:arrayType" 
                 wsdl:arrayType="ElementType<ArrayBounds>"/>
    </restriction>
  </complexContent>
</complexType>

Using this syntax, TypeName specifies the name of the newly-defined array type. ElementType specifies the type of the elements in the array. ArrayBounds specifies the number of dimensions in the array. To specify a single dimension array use []; to specify a two-dimensional array use either [][] or [,].

For example, the SOAP Array, SOAPStrings, shown in Example 11, defines a one-dimensional array of strings. The wsdl:arrayType attribute specifies the type of the array elements, xsd:string, and the number of dimensions, with [] implying one dimension.

Example 11. Definition of a SOAP array

<complexType name="SOAPStrings">
  <complexContent>
    <restriction base="SOAP-ENC:Array">
      <attribute ref="SOAP-ENC:arrayType"
                 wsdl:arrayType="xsd:string[]"/>
    </restriction>
  </complexContent>
</complexType>

You can also describe a SOAP Array using a simple element as described in the SOAP 1.1 specification. The syntax for this is shown in Example 12.

Example 12. Syntax for a SOAP array derived using an element

<complexType name="TypeName">
  <complexContent>
    <restriction base="SOAP-ENC:Array">
      <sequence>
        <element name="ElementName" type="ElementType"
                 maxOccurs="unbounded"/>
      </sequence>
    </restriction>
  </complexContent>
</complexType>

When using this syntax, the element's maxOccurs attribute must always be set to unbounded.

Comments powered by Disqus