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<h1>JiBX Unwrapped document/literal</h1>
<p>Code generation for JiBX data binding converts operations defined by a Web
service to method calls. In the most general case of document/literal
(doc/lit) Web services the generated methods each take a single parameter
object and return a single result object. This type of interface can be
painful for developers because it adds both a layer of indirection and
potentially a large number of extra classes (one input and one output class
for each generated method).</p>
<p>Fortunately, there's an alternative way of generating methods that gives a
much more usable API for many Web services. This alternative is called
<i>unwrapping</i>, and the service definitions that it applies to are called
<i>wrapped</i> definitions. The key difference that qualifies a service
definition as wrapped is the structure of the input and output elements used
for operations.</p>
<p>Here's a sample wrapped WSDL (partial) by way of an example:</p>
<pre>&lt;wsdl:definitions targetNamespace="http://ws.sosnoski.com/library/wsdl"
xmlns:tns="http://ws.sosnoski.com/library/types"
xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/"
xmlns:wsdlsoap="http://schemas.xmlsoap.org/wsdl/soap/"&gt;
&lt;wsdl:types&gt;
&lt;schema elementFormDefault="qualified"
targetNamespace="http://ws.sosnoski.com/library/types"
xmlns="http://www.w3.org/2001/XMLSchema"&gt;
&lt;element name="getBook"&gt;
&lt;complexType&gt;
&lt;sequence&gt;
&lt;element name="isbn" type="string"/&gt;
&lt;/sequence&gt;
&lt;/complexType&gt;
&lt;/element&gt;
&lt;element name="getBookResponse"&gt;
&lt;complexType&gt;
&lt;sequence&gt;
&lt;element name="book" minOccurs="0" type="tns:BookInformation"/&gt;
&lt;/sequence&gt;
&lt;/complexType&gt;
&lt;/element&gt;
&lt;element name="addBook"&gt;
&lt;complexType&gt;
&lt;sequence&gt;
&lt;element name="type" type="string"/&gt;
&lt;element name="isbn" type="string"/&gt;
&lt;element name="author" minOccurs="0" maxOccurs="unbounded" type="string"/&gt;
&lt;element name="title" type="string"/&gt;
&lt;/sequence&gt;
&lt;/complexType&gt;
&lt;/element&gt;
&lt;element name="addBookResponse"&gt;
&lt;complexType&gt;
&lt;sequence&gt;
&lt;element name="success" type="boolean"/&gt;
&lt;/sequence&gt;
&lt;/complexType&gt;
&lt;/element&gt;
&lt;complexType name="BookInformation"&gt;
&lt;sequence&gt;
&lt;element name="author" minOccurs="0" maxOccurs="unbounded" type="string"/&gt;
&lt;element name="title" type="string"/&gt;
&lt;/sequence&gt;
&lt;attribute name="type" use="required" type="string"/&gt;
&lt;attribute name="isbn" use="required" type="string"/&gt;
&lt;/complexType&gt;
&lt;/schema&gt;
&lt;/wsdl:types&gt;
&lt;wsdl:message name="getBookRequest"&gt;
&lt;wsdl:part element="wns:getBook" name="parameters"/&gt;
&lt;/wsdl:message&gt;
&lt;wsdl:message name="getBookResponse"&gt;
&lt;wsdl:part element="wns:getBookResponse" name="parameters"/&gt;
&lt;/wsdl:message&gt;
&lt;wsdl:message name="addBookRequest"&gt;
&lt;wsdl:part element="wns:addBook" name="parameters"/&gt;
&lt;/wsdl:message&gt;
&lt;wsdl:message name="addBookResponse"&gt;
&lt;wsdl:part element="wns:addBookResponse" name="parameters"/&gt;
&lt;/wsdl:message&gt;
&lt;wsdl:portType name="Library"&gt;
&lt;wsdl:operation name="getBook"&gt;
&lt;wsdl:input message="wns:getBookRequest" name="getBookRequest"/&gt;
&lt;wsdl:output message="wns:getBookResponse" name="getBookResponse"/&gt;
&lt;/wsdl:operation&gt;
&lt;wsdl:operation name="addBook"&gt;
&lt;wsdl:input message="wns:addBookRequest" name="addBookRequest"/&gt;
&lt;wsdl:output message="wns:addBookResponse" name="addBookResponse"/&gt;
&lt;/wsdl:operation&gt;
&lt;/wsdl:portType&gt;
...
&lt;/wsdl:definitions&gt;</pre>
<p>This WSDL defines a service with just two operations: <b>getBook</b> and
<b>addBook</b>. The <b>getBook</b> operation takes a <i>getBook</i> element
as input, and returns a <i>getBookResponse</i> element as output, while
<b>addBook</b> takes an <i>addBook</i> element as input and returns an
<i>addBookResponse</i> as output. Each of these input and output elements in
turn consists of a sequence of child elements, with some of the child
elements defined directly using standard schema types and others referencing
user-defined schema types.</p>
<p>As I said up front, this WSDL qualifies for unwrapped handling using JiBX.
Here's the body of the client interface generated when using unwrapping (the
<i>-uw</i> option for WSDL2Java):</p>
<pre> public interface LibraryJibxUnwrapped {
/**
* Auto generated method signatures
* @param type* @param isbn* @param author* @param title
*/
public boolean addBook(
java.lang.String type,java.lang.String isbn,java.lang.String[] author,java.lang.String title) throws java.rmi.RemoteException
;
/**
* Auto generated method signatures
* @param isbn
*/
public com.sosnoski.ws.library.jibx.beans.Book getBook(
java.lang.String isbn) throws java.rmi.RemoteException
;
//
}</pre>
<p>You can see that the JiBX code generation converted the operations into
simple method call interfaces without introducing any extraneous objects (see
<a href="./jibx-doclit-example.html">JiBX Document/Literal Example</a> for
the interface generated when unwrapping is not used). The server-side
interface is the same.</p>
<p>The key points that allow unwrapped handling with JiBX are:</p>
<ol>
<li>Each operation either accepts no input, or the input consists of a
single element.</li>
<li>Each input element is defined as a schema <i>complexType</i> consisting
of a <i>sequence</i> of any number of child elements.</li>
<li>Each operation either generates no output, or the output consists of a
single element.</li>
<li>Each output element is defined as a schema <i>complexType</i>
consisting of a <i>sequence</i> that's either empty or contains a single
child element.</li>
<li>The child elements of both inputs and outputs are defined using
<i>type</i> references, rather than an embedded type definitions.</li>
</ol>
<p>You also need to supply an appropriate JiBX binding definition (using the
<i>-Ebindingfile {file}</i> parameter for WSDL2Java - see <a
href="./jibx-codegen-integration.html#codegen">JiBX Codegen Integration -
WSDL2Java usage</a> for more details). This must define abstract
<i>mapping</i>s for the <i>complexType</i>s referenced by child elements of
the inputs and outputs, with a <i>type-name</i> attribute matching the schema
<i>complexType</i> name. If the child elements reference schema
<i>simpleType</i> definitions the binding must also define a <i>format</i>s
for each <i>simpleType</i>, with a <i>label</i> attribute matching the schema
<i>simpleType</i> name. The binding definition must also specify the
<i>force-classes='true'</i> attribute on the <i>binding</i> element.</p>
<p>For example, here's a binding definition that matches the above WSDL:</p>
<pre>&lt;binding force-classes="true" xmlns:tns="http://ws.sosnoski.com/library/types"&gt;
&lt;namespace uri="http://ws.sosnoski.com/library/types" default="elements"/&gt;
&lt;mapping abstract="true" class="com.sosnoski.ws.library.jibx.beans.Book"
type-name="tns:BookInformation"&gt;
&lt;value name="type" style="attribute" field="m_type"/&gt;
&lt;value name="isbn" style="attribute" field="m_isbn"/&gt;
&lt;collection field="m_authors"&gt;
&lt;value name="author"/&gt;
&lt;/collection&gt;
&lt;value name="title" field="m_title"/&gt;
&lt;/mapping&gt;
&lt;/binding&gt;</pre>
<p>And here's the actual <code>com.sosnoski.ws.library.jibx.beans.Book</code>
class:</p>
<pre>package com.sosnoski.ws.library.jibx.beans;
public class Book
{
private String m_type;
private String m_isbn;
private String m_title;
private String[] m_authors;
public Book() {}
public String getType() {
return m_type;
}
public String getIsbn() {
return m_isbn;
}
public String getTitle() {
return m_title;
}
public String[] getAuthors() {
return m_authors;
}
}</pre>
<p>The JiBX code generation for Axis2 currently requires that classes
coresponding to unwrapped child elements (such as
<code>com.sosnoski.ws.library.jibx.beans.Book</code>, in this case) provide
public default (no-argument) constructors.</p>
<p>JiBX handling allows the child elements of both inputs and outputs to be
optional (with <i>nillable='true'</i>, <i>minOccurs='0'</i>, or both),
providing the binding converts these child elements to object types rather
than primitive types. It also allows repeated child elements (with
<i>minOccurs='unbounded'</i>, or any value of <i>minOccurs</i> greater than
one), representing the repeated elements as arrays of the corresponding
object or primitive types.</p>
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