Package org.codehaus.mojo.jaxb2.schemageneration.postprocessing.schemaenhancement

Class TransformSchema

  • public class TransformSchema
extends Object

    Data holder for schema transformation operations, to permit customization of the schema namespace prefix and file name of generated schema. As the schemagen tool has no mechanics to control namespace prefix and file name of generated schema, the Jaxb2-Maven-plugin must supply a post-processing step to work around this situation.

    Each TransformSchema object holds data pertaining to changes for one namespace URI - either namespace prefix used within the generated XSD or resulting filename for the schema definition.

    1. Namespace prefix. Each XML element within a namespace uses the supplied prefix. (As a reference, in the XML element <foo:bar/>, the namespace prefix is "foo" and the element name is "bar"). The Schemagen tool by default only generates namespace prefixes on the form "ns1", "ns2" etc., which means that the generated schema will contain elements on the form <xs:extension base="ns1:nazgulEntity">. Use a toPrefix element to change the namespace prefix of a particular XML URI to simplify understanding the schema.
    2. Filename. By default, the Schemagen tool creates files called "schema1.xsd", "schema2.xsd" etc. Since the XSD imports one another, simply changing the filename will frequently break the schema structure - you will need to change all import statements in all generated XSD files to match the new file names. The Jaxb2 Maven plugin can do all this housekeeping automatically, if you create a transformSchema element containing a toFile element to change the filename for a particular XML URI. Changing the file names frequently improves overview and usability of the generated schema files.

    Example TransformSchemas

    The URI element is mandatory for each TransformSchema element. The first example illustrates how to use the TransformSchema element to change the prefix and file name of 3 XML URIs. This is the recommended use of a TransformSchema - change both prefix and filename to something meaningful for each URI:

     <transformSchemas>
      <transformSchema>
          <uri>http://some/namespace</uri>
          <toPrefix>some</toPrefix>
          <toFile>some_schema.xsd</toFile>
      </transformSchema>
      <transformSchema>
          <uri>http://another/namespace</uri>
          <toPrefix>another</toPrefix>
          <toFile>another_schema.xsd</toFile>
      </transformSchema>
      <transformSchema>
          <uri>http://yet/another/namespace</uri>
          <toPrefix>yetAnother</toPrefix>
          <toFile>yet_another_schema.xsd</toFile>
      </transformSchema>
 </transformSchemas>

    The URI element is mandatory for each TransformSchema element, along with at least one of the other two elements in the TransformSchema. This implies that partial configuration for TransformSchema can be used, although this is not recommended since the readability and usability of the automatically generated namespace prefixes and file names are poor. The second example illustrates how to use the TransformSchema element to change either prefix or file name for 2 XML URIs:

     <transformSchemas>
      <transformSchema>
          <uri>http://another/namespace</uri>
          <toPrefix>another</toPrefix>
      </transformSchema>
      <transformSchema>
          <uri>http://yet/another/namespace</uri>
          <toFile>yet_another_schema.xsd</toFile>
      </transformSchema>
 </transformSchemas>
    Since:
    1.4
    Author:
    Lennart Jörelid

    • Constructor Detail

      • TransformSchema

        public TransformSchema()
        Default constructor.

      • TransformSchema

        public TransformSchema​(String uri,
                       String toPrefix,
                       String toFile)
        Compound constructor, creating a TransformSchema instruction wrapping the supplied data.
        Parameters:
        uri - The URI of this Schema, such as http://www.jguru.se/some/namespace. Cannot be null or empty.
        toPrefix - The new namespace prefix for this Schema. Optional.
        toFile - The new name of the generated schema file.

    • Method Detail

      • getUri

        public String getUri()
        Returns:
        The URI of this Schema, such as http://www.jguru.se/some/namespace. The namespace URI is mapped to its prefix in the schema element, i.e: xmlns:xs="http://www.w3.org/2001/XMLSchema" or xmlns:foo="http://www.acme.com/xml/schema/foo".

      • getToPrefix

        public String getToPrefix()
        Returns:
        The namespace prefix of this Schema. Each schema element is related to its namespace using the prefix. For an XML element <foo:bar/>, the prefix is "foo" (and the element name is "bar").

      • getToFile

        public String getToFile()
        Returns:
        the name of the target file if/when renamed.

      • setUri

        public void setUri​(String uri)
        Assigns the URI of this Schema, such as http://www.jguru.se/some/namespace. The namespace URI is mapped to its prefix in the schema element, i.e: xmlns:xs="http://www.w3.org/2001/XMLSchema" or xmlns:foo="http://www.acme.com/xml/schema/foo".
        Parameters:
        uri - The non-empty uri of this Schema.

      • setToPrefix

        public void setToPrefix​(String toPrefix)
        Assigns the namespace prefix of this Schema. Each schema element is related to its namespace using the prefix. For an XML element <foo:bar/>, the prefix is "foo" (and the element name is "bar").
        Parameters:
        toPrefix - The non-empty prefix to assign.

      • setToFile

        public void setToFile​(String toFile)
        Assigns the the name of the target file if/when renamed.
        Parameters:
        toFile - The non-empty filename to assign.