Starting with release 1.3.3, the Castor source generator supports a new naming scheme for Java field names, which will be enabled by default. As such, Java field names as generated will follow more closely the standard Java property naming conventions. Should there be a need to keep using the old naming schema, please amend the following property in your custom castorbuilder.properties file:

#
# Property specifying whether for Java field names the old naming conventions
# should be used.
#
# Possible values:
# - true
# - false (default)
# 
# <pre>
# org.exolab.castor.builder.field-naming.old = false
# </pre>
#
org.exolab.castor.builder.field-naming.old=true
	        

With support for Java 5.0 enabled, the generated code will support the following Java 5.0-specific artifacts:

To disable this feature (on by default), please amend the following property in your custom castorbuilder.properties file:

# Specifies whether the sources generated should be source compatible with
# Java 1.4 or Java 5.0. Legal values are "1.4" and "5.0".  When "5.0" is
# selected, generated source will use Java 5 features such as generics and
# annotations.
# Defaults to "5.0".
#
org.exolab.castor.builder.javaVersion=5.0
        

As of Castor 1.0.2, the Castor source generator now supports the generation of Java 5.0 compliant code. The generated code - with the new feature enabled - will make use of the following Java 5.0-specific artifacts:

To enable this feature (off by default), please uncomment the following property in your custom castorbuilder.properties file:

# This property specifies whether the sources generated
# should comply with java 1.4 or 5.0; defaults to 1.4
org.exolab.castor.builder.javaVersion=5.0

In previous versions, castor only supported (un)marshalling of "simple" java5 enums, meaning enums where all facet values are valid java identifiers. In these cases, every enum constant name can be mapped directly to the xml value. See the following example:

<xs:simpleType name="AlphabeticalType">
  <xs:restriction base="xs:string">
    <xs:enumeration value="A"/>
    <xs:enumeration value="B"/>
    <xs:enumeration value="C"/>
  </xs:restriction>
</xs:simpleType>

public enum AlphabeticalType {
    A, B, C
}

<root>
  <AlphabeticalType>A</AlphabeticalType>    
</root>
    

So if there is at least ONE facet that cannot be mapped directly to a valid java identifier, we need to extend the enum pattern. Examples for these cases are value="5" or value="-s". Castor now introduces an extended pattern, similar to the jaxb2 enum handling. The actual value of the enumeration facet is stored in a private String property, the name of the enum constant is translated into a valid identifier. Additionally, some convenience methods are introduced, details about these methods are described after the following example:

<xs:simpleType name="CompositeType">
  <xs:restriction base="xs:string">
    <xs:enumeration value="5"/>
    <xs:enumeration value="10"/>
  </xs:restriction>
</xs:simpleType>

public enum CompositeType {
    VALUE_5("5"),
    VALUE_10("10");

    private final java.lang.String value;

    private CompositeType(final java.lang.String value) {
        this.value = value;
    }

    public static CompositeType fromValue(final java.lang.String value) {
        for (CompositeType c: CompositeType.values()) {
            if (c.value.equals(value)) {
                return c;
            }
        }
        throw new IllegalArgumentException(value);
    }

    public java.lang.String value() {
        return this.value;
    }
    
    public java.lang.String toString() {
        return this.value;
    }
}

<root>
  <CompositeType>5</CompositeType>    
</root>

 # Forces the code generator to create 'old' Java 1.4 enumeration classes instead 
 # of Java 5 enums for xs:simpleType enumerations, even in Java 5 mode.
 #
 # Possible values:
 # - false (default)
 # - true
org.exolab.castor.builder.forceJava4Enums=false

Bound properties are "properties" of a class, which when updated the class will send out a java.beans.PropertyChangeEvent to all registered java.beans.PropertyChangeListeners.

To enable bound properties, please add a property definition to your custom builder configuration file as follows:

# To enable bound properties uncomment the following line. Please
# note that currently *all* fields will be treated as bound properties
# when enabled. This will change in the future when we introduce
# fine grained control over each class and it's properties.
#
org.exolab.castor.builder.boundproperties=true

When enabled, all properties will be treated as bound properties. For each class that is generated a setPropertyChangeListener method is created as follows:

/**
 * Registers a PropertyChangeListener with this class.
 * @param pcl The PropertyChangeListener to register.
 **/

public void addPropertyChangeListener (java.beans.PropertyChangeListener pcl)
{
   propertyChangeListeners.addElement(pcl);
} //-- void addPropertyChangeListener

Whenever a property of the class is changed, a java.beans.PropertyChangeEvent will be sent to all registered listeners. The property name, the old value and the new value will be set in the java.beans.PropertyChangeEvent.

	Note
	To prevent unnecessary overhead, if the property is a collection, the old value will be null.

The source generator can treat the XML Schema structures such as <complexType> and <element> in two main ways. The first, and current default method is called the "element" method. The other is called the "type" method.

To change the "method" of class creation, please add the following property definition to your custom builder configuration file:

# Java class mapping of <xsd:element>'s and <xsd:complexType>'s
#
org.exolab.castor.builder.javaclassmapping=type

Please note that setting this property will not affect class creation when the defaultBindingType is explicitely used in a binding file. In that case, the value set there will take precedence.

The source generator enables the user to set a super class to all the generated classes (of course, class descriptors are not affected by this option). Please note that, though the binding file, it is possible to define a super class for individual classes

To set the global super class, please add the following property definition to your custom builder configuration file:

# This property allows one to specify the super class of *all*
# generated classes
#
org.exolab.castor.builder.superclass=com.xyz.BaseObject

An XML Schema instance is identified by a namespace. For data-binding purposes, especially code generation it may be necessary to map namespaces to Java packages.

This is needed for imported schema in order for Castor to generate the correct imports during code generation for the primary schema.

To allow the mapping between namespaces and Java packages , edit the castorbuilder.properties file :

# XML namespace mapping to Java packages
#
#org.exolab.castor.builder.nspackages=\
   http://www.xyz.com/schemas/project=com.xyz.schemas.project,\
   http://www.xyz.com/schemas/person=com.xyz.schemas.person

Since version: 0.9.1

The Source Generator can override the equals() and hashCode() method for the generated objects.

To have equals() and hashCode() methods generated, override the following property in your custom castorbuilder.properties file:

# Set to true if you want to have an equals() and 
# hashCode() method generated for each generated class;
# false by default
org.exolab.castor.builder.equalsmethod=true

Since version: 1.3.2

Specifies whether cycle breaker code should be added to generated methods equals() and hashcode().

# Property specifying whether cycle breaker code should be added
# to generated methods 'equals' and 'hashcode'. 
#
# Possible values:
# - true (default)
# - false
#
# <pre>
# org.exolab.castor.builder.useCycleBreaker
# </pre>
org.exolab.castor.builder.useCycleBreaker=true

Since version 0.9.4

It may be convenient to use java objects instead of primitives, the Source Generator provides a way to do it. Thus the following mapping can be used:

To enable this property, edit the castor builder.properties file:

# Set to true if you want to use Object Wrappers instead
# of primitives (e.g Float instead of float).
# false by default.
#org.exolab.castor.builder.primitivetowrapper=false

Since version 1.1.1

With this property enabled, the XML code generator will use a new automatic class name resolution mode that has special logic implemented to automatically resolve class name conflicts.

This new mode deals with various class name conflicts where previously a binding file had to be used to resolve these conflicts manually.

To enable this feature (turned off by default), please add the following property definitio to your custom castorbuilder.properties file:

# Specifies whether automatic class name conflict resolution
# should be used or not; defaults to false.
#
org.exolab.castor.builder.automaticConflictResolution=true

Specifies whether extra (additional) methods should be created for collection-style fields. Set this to true if you want your code to be more compatible with Castor JDO (or other persistence frameworks in general).

By setting this property to true, additional getter/setter methods for the field in question, such as get/set by reference and set as copy methods, will be added. In order to have these additional methods generated, please override the following code generator property in a custom castorbuilder.properties as shown:

# Enables generation of extra methods for collection fields, such as get/set by
# reference and set as copy.  Extra methods are in addition to the usual
# collection get/set methods.  Set this to true if you want your code to be
# more compatible  with Castor JDO.
#
# Possible values:
# - false (default) 
# - true
org.exolab.castor.builder.extraCollectionMethods=true
            

As of release 1.2, Castor supports the use of Velocity-based code templates for code generation. For the time being, Castor will support two modes for code generation, i.e. the new Velocity-based and an old legacy mode. Default will be the legacy mode; this will be changed with a later release of Castor.

In order to use the new Velocity-based code generation, please call the method setJClassPrinterType(String) on org.exolab.castor.builder.SourceGenerator with a value of velocity.

As we consider the code stable enough for a major release, we do encourage users to use the new Velocity-based mode and to provide us with (valuable) feedback.

Please note that we have changed the mechanics of changing the JClass printing type between releases 1.2 and 1.2.1.

As of release 1.2, the Castor XML code generator - if configured as shown below - now supports generation of additional methods to allow programmatic access to <xs:documentation> elements for top-level type/element definitions as follows:

public java.lang.String getXmlSchemaDocumentation(final java.lang.String source);
public java.util.Map getXmlSchemaDocumentations();

In order to have these additional methods generated as shown above, please override the following code generator property in a custom castorbuilder.properties as shown:

# Property specifying whether extra members/methods for extracting XML schema
# documentation should be made available; defaults to false
org.exolab.castor.builder.extraDocumentationMethods=true

<binding
    defaultBindingType = (element|type)>
    (include*,
     package*,
     namingXML?,
     elementBinding*,
     attributeBinding,
     complexTypeBinding,
     groupBinding)
</binding>

The binding element is the root element and contains the binding information.

<include
    URI = xsd:anyURI/>

This element allows you to include a binding declaration defined in another file. This allows reuse of binding files defined for various XML schemas.

<package>
    name = xsd:string
    (namespace|schemaLocation) = xsd:string>
</package>

The targetNamespace attribute of an XML schema identifies the namespace in which the XML schema elements are defined. This language namespace is defined in the generated Java source as a package declaration. The <package/> element allows you to define the mapping between an XML namespace and a Java package.

Moreover, XML schema allows you to factor the definition of an XML schema identified by a unique namespace by including several XML schemas instances to build one XML schema using the <xsd:include/> element. Please make sure you understand the difference between <xsd:include/> and <xsd:import/>. <xsd:include/> # relies on the URI of the included XML schema. This element allows you to keep the structure hierarchy defined in XML schema in a single generated Java package. Thus the binding file allows you to define the mapping between a schemaLocation attribute and a Java package.

<namingXML>
   (elementName,complexTypeName,modelGroupName)
</namingXML>

<elementName|complexTypeName|modelGroupName>
    (prefix?, suffix?) = xsd:string
</elementName|complexTypeName|modelGroupName>

One of the aims of the binding file is to avoid naming collisions. Indeed, XML schema allows <element>s and <complexType>s to share the same name, resulting in name collisions when generating sources. Defining a binding for each element and complexType that share the same name is not always a convenient solution (for instance the BPML XML schema and the UDDI v2.0 XML schema use the same names for top-level complexTypes and top-level elements).

The main aim of the <namingXML/> element is to define default prefices and suffices for the names of the classes generated for an <element>, a <complexType> or a model group definition.

	Note
	It is not possible to control the names of the classes generated to represent nested model groups (all, choice, and sequence).

<elementBinding|attributeBinding|complexTypeBinding|groupBinding
    name = xsd:string>
   ((java-class|interface|member|contentMember),
     elementBinding*,
     attributeBinding*,
     complexTypeBinding*,
     groupBinding*)
</elementBinding|attributeBinding|complexTypeBinding|groupBinding>

These elements are the tenets of the binding file since they contain the binding definition for an XML schema element, attribute, complex type and model group definition. The first child element (<java-class/>, <interface>, <member> or <contentMember/>) will determine the type of binding one is defining. Please note that defining a <java-class> binding on an XML schema attribute will have absolutely no effect.

The binding file is written from an XML schema point of view; there are two distinct ways to define the XML schema component for which we are defining a binding.

[1]Path         ::= '/'LocationPath('/'LocationPath)*
[2]LocationPath ::= (Complex|ModelGroup|Attribute|Element|Enumeration)
[3]Complex      ::= 'complexType:'(NCName)
[4]ModelGroup   ::= 'group:'NCName
[5]Attribute    ::= '@'NCName
[6]Element      ::= NCName
[7]Enumeration  ::= 'enumType':(NCName)
                    

<complexType name="fooType">
    <sequence>
        <element name="foo" type="string" />
    </sequence>
</complexType>

<elementBinding name="/complexType:fooType/foo>
   <member name="MyFoo" handler="mypackage.myHandler"/>
</elementBinding>

<complexTypeBinding name="/fooType">
   <elementBinding name="/foo>
      <member name="MyFoo" handler="mypackage.myHandler"/>
   </elementBinding>
<complexTypeBinding>

<java-class
    name? = xsd:string
    package? = xsd:string
    final? = xsd:boolean
    abstract? = xsd:boolean
    equals? = xsd:boolean
    bound? = xsd:boolean
    (implements*,extends?)
</java-class>

This element defines all the options for the class to be generated, including common properties such as class name, package name, and so on.

For instance, the following binding definition instructs the source generator to generate a class CustomTest for a global element named 'test', replacing the default class name Test with CustomTest.

<elementBinding name="/test">
   <java-class name="CustomTest" final="true"/>
</elementBinding>

In addition to the properties listed above, it is possible to define that the class generated will extend a class given and/or implement one or more interfaces.

For instance, the following binding definition instructs the source generator to generate a class TestWithInterface that implements the interface org.castor.sample.SomeInterface in addition to java.io.Serializable.

<elementBinding name="/test">
   <java-class name="TestWithInterface">
      <implements>org.castor.sample.SomeInterface</implements>
   </java-class>
</elementBinding>
                 

The subsequent binding definition instructs the source generator to generate a class TestWithExtendsAndInterface that implements the interface org.castor.sample.SomeInterface in addition to java.io.Serializable, and extends from a (probably abstract) base class SomeAbstractBaseClass.

<elementBinding name="/test">
   <java-class name="TestWithExtendsAndInterface">
      <extends>org.castor.sample.SomeAbstractBaseClass</extends>
      <implements>org.castor.sample.SomeInterface</implements>
   </java-class>
</elementBinding>
                 

The generated class SomeAbstractBaseClass will have a class signature as shown below:

...

public class TestWithExtendsAndInterface
   extends SomeAbstractBaseClass
   implements SomeInterface, java.io.Serializable {
   ...
                 

 <member
  name? = xsd:string
  java-type? = xsd:string
  wrapper? = xsd:boolean
  handler? = xsd:string
  visibility? = (public|protected|private)
  collection? = (array|vector|arraylist|hashtable|collection|odmg|set|map|sortedset)
  validator? = xsd:string/>

This element represents the binding for class member. It allows the definition of its name and java type as well as a custom implementation of FieldHandler to help the Marshaling framework in handling that member. Defining a validator is also possible. The names given for the validator and the fieldHandler must be fully qualified.

For instance, the following binding definition:

<elementBinding name="/root/members">
   <member collection="set"/>
</elementBinding>

instructs the source generator to generate -- within a class Root -- a Java member named members using the collection type java.util.Set instead of the default java.util.List:

         public class Root {
         
            private java.util.Set members;
         
            ...
         
         }

The following (slightly amended) binding element:

<elementBinding name="/root/members">
   <member name="memberSet" collection="set"/>
</elementBinding>

instructs the source generator to generate -- again within a class Root -- a Java member named memberSet (of the same collection type as in the previous example), overriding the name of the member as specified in the XML schema:

public class Root {

   private java.util.Set memberSet;

   ...

}

          <contentMember
           name? = xsd:string
           visiblity? = (public|protected|private)

This element represents the binding for content class member generated as a result of a mixed mode declaration of a complex type definition. It allows the definition of its name and its visibility

For a complex type definition declared to be mixed such as follows ...

<complexType name="RootType" mixed="true">
   <sequence>
      ...
   >/sequence>
>/complexType>

... the following binding definition ...

<elementBinding name="/complexType:RootType">
   <contentMember name="customContentMember"/>
</elementBinding>

instructs the source generator to generate -- within a class RootType -- a Java member named customContentMember of type java.lang.String:

public class RootType {

   private java.util.String customContentMember;

   ...
}

<enumBinding>
   (enumDef)
</enumBinding>

<enumDef>
   (enumClassName = xsd:string, enumMember*)
</enumDef>

<enumMember>
   (name = xsd:string, value = xsd:string)
</enumMember>

The <enumBinding> element allows more control on the code generated for type-safe enumerations, which are used to represent an XML Schema <simpleType> enumeration.

For instance, given the following XML schema enumeration definition:

<xs:simpleType name="durationUnitType">
  <xs:restriction base='xs:string'>
    <xs:enumeration value='Y' />
    <xs:enumeration value='M' />
    <xs:enumeration value='D' />
    <xs:enumeration value='h' />
    <xs:enumeration value='m' />
    <xs:enumeration value='s' />
  </xs:restriction>
</simpleType>

the Castor code generator would generate code where the default naming convention used during the generation would overwrite the first constant definition for value 'M' with the one generated for value 'm'.

The following binding definition defines -- through the means of an <enumMember> definition for the enumeration value 'M' -- a special binding for this value:

<enumBinding name="/enumType:durationUnitType">
  <enum-def>
    <enumMember>
      <value>M</value>
      <javaName>CUSTOM_M</javaName>
    </enumMember>
  </enum-def>
</enumBinding>

and instructs the source generator to generate -- within a class DurationUnitType -- a constant definition named CUSTOM_M for the enumeration value M.

During code generation, the Castor XML code generator will run into situations where a class (about to be generated, and as such about to be written to the file system) will overwrite an already existing class. This, for example, is the case if within one XML schema there's two (local) element definitions within separate complex type definitions with the same name. In such a case, Castor will emit warning messages that inform the user that a class will be overwritten.

As of release 1.1, the Castor XML code generator supports two reporting modes that allow different levels of control in the event of such collisions, warnViaConsoleDialog and informViaLog mode.

Please select the reporting mode of your choice according to your needs, the default being warnViaConsoleDialog. Please note that the informViaLog reporting mode should be the preferred choice when using the XML code generator in an automated environment.

In general, the warning messages produced are very useful in assisting you in your creation of the binding file, as shown in below example for the warnViaConsoleDialog mode:

 Warning: A class name generation conflict has occurred between element
         '/Data/OrderReceipt/LineItem' and element '/Data/PurchaseOrder/LineItem'.
         Please use a Binding file to solve this problem.Continue anyway [not recommended] (y|n|?)y
 Warning: A class name generation conflict has occurred between element
         '/Data/OrderReceipt/LineItem' and element '/Data/PurchaseOrder/LineItem'.
         Please use a Binding file to solve this problem.Continue anyway [not recommended] (y|n|?)y
 Warning: A class name generation conflict has occurred between element
         '/Data/OrderReceipt/LineItem' and element '/Data/PurchaseOrder/LineItem'.
         Please use a Binding file to solve this problem.Continue anyway [not recommended] (y|n|?)y
 Warning: A class name generation conflict has occurred between element
         'complexType:ReceiptLineItemType/Sku' and element 'complexType:LineItemType/Sku'.
         Please use a Binding file to solve this problem.Continue anyway [not recommended] (y|n|?)y
 Warning: A class name generation conflict has occurred between element
         'complexType:ReceiptLineItemType/Sku' and element 'complexType:LineItemType/Sku'.
         Please use a Binding file to solve this problem.Continue anyway [not recommended] (y|n|?)y
 Warning: A class name generation conflict has occurred between element
         'complexType:ReceiptLineItemType/Sku' and element 'complexType:LineItemType/Sku'.
         Please use a Binding file to solve this problem.Continue anyway [not recommended] (y|n|?)y
                         

As of Castor 1.1.1, support has been added to the Castor XML code generator for a (nearly) automatic conflict resolution. To enable this new mode, please override the following property in your custom property file as shown below:

 # Specifies whether automatic class name conflict resolution
 # should be used or not; defaults to false.
 #
 org.exolab.castor.builder.automaticConflictResolution=true

As a result of enabling automatic conflict resolution, Castor will try to resolve such name collisions automatically, using one of the following two strategies:

In order to explain the modus operandi of these two modes, please assume two complex type definitions AType and BType in an XML schema, with both of them defining a local element named c.

<xs:complexType name="AType">
    <xs:sequence>
        <xs:element name="c" type="CType1" />
    </xs:sequence>
</xs:complexType>            

<xs:complexType name="BType">
    <xs:sequence>
        <xs:element name="c" type="CType2" />
    </xs:sequence>
</xs:complexType>

Without automatic collision resolution enabled, Castor will create identically named classes C.java for both members, and one will overwrite the other. Please note the different types for the two c element definitions, which requires two class files to be generated in order not to lose this information.

# Property specifying the 'string' used in type strategy to be inserted 
# between the actual element name and the type name (during automatic class name 
# conflict resolution); defaults to 'By'.
org.exolab.castor.builder.automaticConflictResolutionTypeSuffix=ByBy

2.4.2.2.4. Conflicts covered

The Castor XML code generator, with automatic collision resolution enabled, is capable of resolving the following collisions automatically:

• Name of local element definition same as name of a global element

• Name of local element definition same as name of another local element definition.

	Note
	Please note that collision resolution for a local to local collision will only take place for the second local element definition encountered (and subsequent ones).

As shown in the subsequent table, there's multiple ways of specifying the input for the Castor code generator. At least one input source has to be specified.

In addition, a nested <fileset> can be specified as the source of input. Please refer to the samples shown below.

Please find below the complete list of parameters that can be set on the Castor source generator to fine-tune the execution behavior.

To be able to start source code generation from XML schema from within Maven, you will have to configure the Maven 2 Castor plugin as follows:

<plugin>
   <groupId>org.codehaus.mojo</groupId>
   <artifactId>castor-maven-plugin</artifactId>
   <version>2.0</version>
</plugin>

Above configuration will trigger source generation using the default values as explained at the Castor plugin page, assuming that the XML schema(s) are located at src/main/castor, and code will be saved at target/generated-sources/castor. When generating sources for multiple schemas at the same time, you can put namespace to package mappings into src/main/castor/castorbuilder.properties.

To e.g. change some of these default locations, please add a <configuration> section to the plugin configuration as follows:

<plugin>
   <groupId>org.codehaus.mojo</groupId>
   <artifactId>castor-maven-plugin</artifactId>
   <version>2.0</version>
   <configuration>
      <schema>src/main/resources/org/exolab/castor/builder/binding/binding.xsd</schema>
      <packaging>org.exolab.castor.builder.binding</packaging>
      <properties>src/main/resources/org/exolab/castor/builder/binding.generation.properties</properties>
   </configuration>
 </plugin>      

Details on the available configuration properties can be found here.

By default, the Maven Castor plugin has been built and tested against a particular version of Castor. To switch to a newer version of Castor (not the plugin itself), please use a <dependencies> section as shown below to point the plugin to e.g. a newer version of Castor:

<plugin>
   <groupId>org.codehaus.mojo</groupId>
   <artifactId>castor-maven-plugin</artifactId>
   <version>2.0</version>
   <dependencies>
     <dependency> 
       <groupId>org.codehaus.castor</groupId>
       <artifactId>castor</artifactId>
       <version>1.3.1-SNAPSHOT</version>
     </dependency>
   </dependencies>
 </plugin>      

To integrate source code generation from XML schema into your standard build life-cycle, you will have to add an <executions> section to your standard plugin configuration as follows:

<plugin>
   <groupId>org.codehaus.mojo</groupId>
   <artifactId>castor-maven-plugin</artifactId>
   <version>2.0</version>
   <executions>
      <execution>
         <goals>
            <goal>generate</goal>
         </goals>
      </execution>
   </executions>            
</plugin>       

Below command shows how to instruct Maven (manually) to generate Java sources from the XML schemas as configured above.

> mvn castor:generate

java org.exolab.castor.builder.SourceGeneratorMain -i foo-schema.xsd \
    -package com.xyz
            

This will generate a set of source files from the the XML Schema foo-schema.xsd and place them in the package com.xyz.

To compile the generated classes, simply run javac or your favorite compiler:

javac com/xyz/*.java

Created class will have marshal and unmarshal methods which are used to go back and forth between XML and an Object instance.

The source code generator has a number of different options which may be set. Some of these are done using the command line and others are done using a properties file located by default at org/exolab/castor/builder/castorbuilder.properties.

-types com.personal.MyCoolFactory

	Tip
	For additional information about the Source Generator and its options, you can download the Source Generator User Document (PDF). Please note that the use of a binding file is not dicussed in that document.

Grouping support covers both model group definitions (<group>) and model groups (<all>, <choice> and <sequence>). In this section we will label as a 'nested group' any model group whose first parent is another model group.

<any> is supported and will be mapped to an AnyNode instance. However, full namespace validation is not yet implemented, even though an AnyNode structure is fully namespace aware.

<anyAttribute> is currently not supported. It is a work in progress.

The input file is the schema file given with the XML code generator example in the distribution of Castor (under /src/examples/SourceGenerator/invoice.xsd).

<?xml version="1.0"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
    targetNamespace="http://castor.exolab.org/Test/Invoice">

    <xsd:annotation>
        <xsd:documentation>
            This is a test XML Schema for Castor XML.
        </xsd:documentation>
    </xsd:annotation>

    <!--
        A simple representation of an invoice. This is simply an example
        and not meant to be an exact or even complete representation of an invoice.
    -->
    <xsd:element name="invoice">
        <xsd:annotation>
            <xsd:documentation>
                A simple representation of an invoice
            </xsd:documentation>
        </xsd:annotation>

        <xsd:complexType>
            <xsd:sequence>
                <xsd:element name="ship-to">
                    <xsd:complexType>
                        <xsd:group ref="customer" />
                    </xsd:complexType>
                </xsd:element>
                <xsd:element ref="item"
                    maxOccurs="unbounded" minOccurs="1" />
                <xsd:element ref="shipping-method" />
                <xsd:element ref="shipping-date" />
            </xsd:sequence>
        </xsd:complexType>
    </xsd:element>

    <!-- Description of a customer -->
    <xsd:group name="customer">
        <xsd:sequence>
            <xsd:element name="name" type="xsd:string" />
            <xsd:element ref="address" />
            <xsd:element name="phone"
                type="TelephoneNumberType" />
        </xsd:sequence>
    </xsd:group>

    <!-- Description of an item -->
    <xsd:element name="item">
        <xsd:complexType>
            <xsd:sequence>
                <xsd:element name="Quantity"
                    type="xsd:integer" minOccurs="1" maxOccurs="1" />
                <xsd:element name="Price" type="PriceType"
                    minOccurs="1" maxOccurs="1" />
            </xsd:sequence>
            <xsd:attributeGroup ref="ItemAttributes" />
        </xsd:complexType>
    </xsd:element>

    <!-- Shipping Method -->
    <xsd:element name="shipping-method">
        <xsd:complexType>
            <xsd:sequence>
                <xsd:element name="carrier"
                    type="xsd:string" />
                <xsd:element name="option"
                    type="xsd:string" />
                <xsd:element name="estimated-delivery"
                    type="xsd:duration" />
            </xsd:sequence>
        </xsd:complexType>
    </xsd:element>

    <!-- Shipping date -->
    <xsd:element name="shipping-date">
        <xsd:complexType>
            <xsd:sequence>
                <xsd:element name="date" type="xsd:date" />
                <xsd:element name="time" type="xsd:time" />
            </xsd:sequence>
        </xsd:complexType>
    </xsd:element>

    <!-- A simple U.S. based Address structure -->
    <xsd:element name="address">
        <xsd:annotation>
            <xsd:documentation>
                Represents a U.S. Address
            </xsd:documentation>
        </xsd:annotation>

        <xsd:complexType>
            <xsd:sequence>
                <!-- street address 1 -->
                <xsd:element name="street1"
                    type="xsd:string" />
                <!-- optional street address 2 -->
                <xsd:element name="street2"
                    type="xsd:string" minOccurs="0" />
                <!-- city-->
                <xsd:element name="city" type="xsd:string" />
                <!-- state code -->
                <xsd:element name="state"
                    type="stateCodeType" />
                <!-- zip-code -->
                <xsd:element ref="zip-code" />
            </xsd:sequence>
        </xsd:complexType>
    </xsd:element>

    <!-- A U.S. Zip Code -->
    <xsd:element name="zip-code">
        <xsd:simpleType>
            <xsd:restriction base="xsd:string">
                <xsd:pattern value="[0-9]{5}(-[0-9]{4})?" />
            </xsd:restriction>
        </xsd:simpleType>
    </xsd:element>

    <!-- State Code
        obviously not a valid state code....but this is just
        an example and I don't feel like creating all the valid
        ones.
    -->
    <xsd:simpleType name="stateCodeType">
        <xsd:restriction base="xsd:string">
            <xsd:pattern value="[A-Z]{2}" />
        </xsd:restriction>
    </xsd:simpleType>

    <!-- Telephone Number -->
    <xsd:simpleType name="TelephoneNumberType">
        <xsd:restriction base="xsd:string">
            <xsd:length value="12" />
            <xsd:pattern value="[0-9]{3}-[0-9]{3}-[0-9]{4}" />
        </xsd:restriction>
    </xsd:simpleType>

    <!-- Cool price type -->
    <xsd:simpleType name="PriceType">
        <xsd:restriction base="xsd:decimal">
            <xsd:fractionDigits value="2" />
            <xsd:totalDigits value="5" />
            <xsd:minInclusive value="1" />
            <xsd:maxInclusive value="100" />
        </xsd:restriction>
    </xsd:simpleType>

    <!-- The attributes for an Item -->
    <xsd:attributeGroup name="ItemAttributes">
        <xsd:attribute name="Id" type="xsd:ID" minOccurs="1"
            maxOccurs="1" />
        <xsd:attribute name="InStock" type="xsd:boolean"
            default="false" />
        <xsd:attribute name="Category" type="xsd:string"
            use="required" />
    </xsd:attributeGroup>
</xsd:schema>

The structure of this schema is simple: it is composed of a top-level element which is a complexType with references to other elements inside. This schema represents a simple invoice: an invoice is a customer (customer top-level group), an article (item element), a shipping method (shipping-method element) and a shipping date (shipping-date element). Notice that the ship-to element uses a reference to an address element. This address element is a top-level element that contains a reference to a non-top-level element (the zip-cod element). At the end of the schema we have two simpleTypes for representing a telephone number and a price. The Source Generator is used with the element property set for class creation so a class is going to be generated for all top-level elements. No classes are going to be generated for complexTypes and simpleTypes since the simpleType is not an enumeration.

To summarize, we can expect 7 classes : Invoice, Customer, Address, Item, ShipTo, ShippingMethod and ShippingDate and the 7 corresponding class descriptors. Note that a class is generated for the top-level group customer

To run the source generator and create the source from the invoice.xsd file in a package test, we just call in the command line:

java -cp %CP% org.exolab.castor.builder.SourceGeneratorMain -i invoice.xsd -package test

            <title>supplyChainV1.0.xsd</title>
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
           elementFormDefault="qualified"
           attributeFormDefault="unqualified">

    <xs:element name="Data">
      <xs:annotation>
        <xs:documentation>
          This section contains the supply chain message data
        </xs:documentation>
      </xs:annotation>
      <xs:complexType>
        <xs:choice>
          <xs:element name="PurchaseOrder">
            <xs:complexType>
              <xs:sequence>
                <xs:element name="LineItem" type="LineItemType" maxOccurs="unbounded"/>
              </xs:sequence>
              <xs:attribute name="OrderNumber" type="xs:string" use="required"/>
            </xs:complexType>
          </xs:element>
          <xs:element name="OrderReceipt">
            <xs:complexType>
              <xs:sequence>
                <xs:element name="LineItem" type="ReceiptLineItemType" maxOccurs="unbounded"/>
              </xs:sequence>
              <xs:attribute name="OrderNumber" type="xs:string" use="required"/>
            </xs:complexType>
          </xs:element>
        </xs:choice>
      </xs:complexType>
    </xs:element>

    <xs:complexType name="SkuType">
      <xs:annotation>
        <xs:documentation>Contains Product Identifier</xs:documentation>
      </xs:annotation>
      <xs:sequence>
        <xs:element name="Number" type="xs:integer"/>
        <xs:element name="ID" type="xs:string"/>
      </xs:sequence>
    </xs:complexType>

    <xs:complexType name="ReceiptSkuType">
      <xs:annotation>
        <xs:documentation>Contains Product Identifier</xs:documentation>
      </xs:annotation>
      <xs:complexContent>
        <xs:extension base="SkuType">
          <xs:sequence>
            <xs:element name="InternalID" type="xs:string"/>
          </xs:sequence>
        </xs:extension>
      </xs:complexContent>
    </xs:complexType>

    <xs:complexType name="LineItemType">
      <xs:sequence>
        <xs:element name="Sku" type="SkuType"/>
        <xs:element name="Value" type="xs:double"/>
        <xs:element name="BillingInstructions" type="xs:string"/>
        <xs:element name="DeliveryDate" type="xs:date"/>
        <xs:element name="Number" type="xs:integer"/>
      </xs:sequence>
    </xs:complexType>

    <xs:complexType name="ReceiptLineItemType">
      <xs:sequence>
        <xs:element name="Sku" type="ReceiptSkuType"/>
        <xs:element name="Value" type="xs:double"/>
        <xs:element name="PackingDescription" type="xs:string"/>
        <xs:element name="ShipDate" type="xs:dateTime"/>
        <xs:element name="Number" type="xs:integer"/>
      </xs:sequence>
    </xs:complexType>
</xs:schema>

If you run the Castor CodeGenerator on the above XSD you end up with the following set of classes. (You also get lots of warning messages with the present version.)

Data.java
DataDescriptor.java
LineItem.java
LineItemDescriptor.java
LineItemType.java
LineItemTypeDescriptor.java
OrderReceipt.java
OrderReceiptDescriptor.java
PurchaseOrder.java
PurchaseOrderDescriptor.java
ReceiptLineItemType.java
ReceiptLineItemTypeDescriptor.java
ReceiptSkuType.java
ReceiptSkuTypeDescriptor.java
Sku.java
SkuDescriptor.java
SkuType.java
SkuTypeDescriptor.java

The problem here is that there are two different elements with the same name in different locations in the XSD. This causes a Java code generation conflict. By default, Castor uses the element name as the name of the class. So the second class generated for the LineItem definition, which is different than the first, overwrites the first class generated.

A binding file is therefore necessary to help the Castor code generator differentiate between these generated classes and as such avoid such generation conflicts. That is, you can 'bind' an element in the XML schema to a differently named class file that you want to generate. This keeps different elements separate and ensures that source is properly generated for each XML Schema object.

Tip

The warning messages for Castor 0.99+ are very useful in assisting you in your creation of the binding file. For the example the warning messages for the example are: Warning: A class name generation conflict has occurred between element '/Data/OrderReceipt/LineItem' and element '/Data/PurchaseOrder/LineItem'. Please use a Binding file to solve this problem.Continue anyway [not recommended] (y|n|?)y Warning: A class name generation conflict has occurred between element '/Data/OrderReceipt/LineItem' and element '/Data/PurchaseOrder/LineItem'. Please use a Binding file to solve this problem.Continue anyway [not recommended] (y|n|?)y Warning: A class name generation conflict has occurred between element '/Data/OrderReceipt/LineItem' and element '/Data/PurchaseOrder/LineItem'. Please use a Binding file to solve this problem.Continue anyway [not recommended] (y|n|?)y Warning: A class name generation conflict has occurred between element 'complexType:ReceiptLineItemType/Sku' and element 'complexType:LineItemType/Sku'. Please use a Binding file to solve this problem.Continue anyway [not recommended] (y|n|?)y Warning: A class name generation conflict has occurred between element 'complexType:ReceiptLineItemType/Sku' and element 'complexType:LineItemType/Sku'. Please use a Binding file to solve this problem.Continue anyway [not recommended] (y|n|?)y Warning: A class name generation conflict has occurred between element 'complexType:ReceiptLineItemType/Sku' and element 'complexType:LineItemType/Sku'. Please use a Binding file to solve this problem.Continue anyway [not recommended] (y|n|?)y

The following binding file definition will overcome the naming issues for the generated classes:

            
<binding xmlns="http://www.castor.org/SourceGenerator/Binding"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://www.castor.org/SourceGenerator/Binding C:\\Castor\\xsd\\binding.xsd"
         defaultBinding="element">

   <elementBinding name="/Data/PurchaseOrder/LineItem">
      <java-class name="PurchaseOrderLineItem"/>
   </elementBinding>

   <elementBinding name="/Data/OrderReceipt/LineItem">
      <java-class name="OrderReceiptLineItem"/>
   </elementBinding>

   <elementBinding name="/complexType:ReceiptLineItemType/Sku">
      <java-class name="OrderReceiptSku"/>
   </elementBinding>

   <elementBinding name="/complexType:LineItemType/Sku">
      <java-class name="PurchaseOrderSku"/>
   </elementBinding>

</binding>

One thing to notice in the above binding.xml file is that the name path used is relative to the root of the XSD and not the root of the target XML. Also notice that the two complex types have the "complexType:" prefix to identify them followed by the name path relative to the root of the XSD.

The new list of generated classes is:

Data.java
DataDescriptor.java
LineItem.java
LineItemDescriptor.java
LineItemType.java
LineItemTypeDescriptor.java
OrderReceipt.java
OrderReceiptDescriptor.java
OrderReceiptLineItem.java
OrderReceiptLineItemDescriptor.java
OrderReceiptSku.java
OrderReceiptSkuDescriptor.java
PurchaseOrder.java
PurchaseOrderDescriptor.java
PurchaseOrderLineItem.java
PurchaseOrderLineItemDescriptor.java
PurchaseOrderSku.java
PurchaseOrderSkuDescriptor.java
ReceiptLineItemType.java
ReceiptLineItemTypeDescriptor.java
ReceiptSkuType.java
ReceiptSkuTypeDescriptor.java
Sku.java
SkuDescriptor.java
SkuType.java
SkuTypeDescriptor.java

The developers can now use these generated classes with Castor to (un)marshal the supply chain messages sent by their business partner.