6
XML Schema Processor for Java

This chapter contains the following sections:

• Introducing XML Schema
• Oracle XML Schema Processor for Java Features
• XML Schema Processor for Java Usage
• How to Run the XML Schema for Java Sample Program

Introducing XML Schema

XML Schema was created by the W3C to describe the content and structure of XML documents in XML. It includes the full capabilities of DTDs (Document Type Descriptions) so that existing DTDs can be converted to XML Schema. XML Schemas have additional capabilities compared to DTDs.

How DTDs and XML Schema Differ

Document Type Definition (DTD) is a mechanism provided by XML 1.0 for declaring constraints on XML markup. DTDs allow the specification of the following:

• Which elements can appear in your XML documents
• What elements can be in the elements
• The order the elements can appear

XML Schema language serves a similar purpose to DTDs, but it is more flexible in specifying XML document constraints and potentially more useful for certain applications. See the following section "DTD Limitations".

Consider the XML document:

<?XML version="1.0">
<publisher pubid="ab1234">
  <publish-year>2000</publish-year>
     <title>The Cat in the Hat</title>
     <author>Dr. Seuss</author>
     <artist>Ms. Seuss</artist>
     <isbn>123456781111</isbn>
</publisher>

Consider a typical DTD for the foregoing XML document:

<!ELEMENT publisher (year,title, author+, artist?, isbn)>
<!ELEMENT publish-year (#PCDATA)>
<!ELEMENT title (#PCDATA)>
<!ELEMENT author (#PCDATA)>
<!ELEMENT isbn (#PCDATA)>
...

DTD Limitations

DTDs, also known as XML Markup Declarations, are considered to be deficient in handling certain applications including the following:

• Document authoring and publishing
• Exchange of metadata
• E-commerce
• Inter-database operations

DTD limitations include:

• DTD is not integrated with Namespace technology so users cannot import and reuse code
• DTD does not support data types other than character data, a limitation for describing metadata standards and database schemas
• Applications need to specify document structure constraints more flexibly than the DTD allows for

XML Schema Features

Table 6-1, "XML Schema Features" lists XML Schema features. Note that XML Schema features include DTD features.

Table 6-1 XML Schema Features  

XML Schema Feature	DTD
Built-In Data Types XML schema specifies a set of builtin datatypes. Some of them are defined and called primitive datatypes, and they form the basis of the type system: string, boolean, float, decimal, double, duration, dateTime, time, date, gYearMonth, gYear, gMonthDat, gMonth, gDay, Base64Binary, HexBinary, anyURI, NOTATION, QName. Others are derived datatypes that are defined in terms of primitive types.	DTDs do not support data types other than character strings.
User-Defined Data Types Users can derive their own datatypes from the builtin data types. There are three ways of datatype derivation: restriction, list and union. Restriction defines a more restricted data type by applying constraining facets to the base type, list simply allows a list of values of its item type, and union defines a new type whose value can be of any of its member types. For example, to specify that the value of publish-year type to be within a specific range: <SimpleType name = "publish-year"> <restriction base="gYear"> <minInclusive value="1970"/> <maxInclusive value="2000"/> </restriction> </SimpleType> The constraining facets are: length, minLength, maxLength, pattern, enumeration, whiteSpace, maxInclusive, maxExclusive, minInclusive, minExclusive, totalDigits, fractionDigits. Some facets only apply to certain base types. Note that several facets have been changed since the first release of Oracle XML Schema Processor for Java.	The publish-year element in the DTD example cannot be constrained further.
Occurrence Indicators (Content Model or Structure) In XML Schema, the structure (called complexType) of the instance document or an element is defined in terms of model group and attribute group. A model group may further contain model groups or element particles, while attribute group contains attributes. Wildcards can be used in both model group and attribute group to indicate any element or attribute. There are three varies of model group: sequence, all, and choice, representing the sequence, conjunction and disjunction relationships among particles respectively. The range of the number of occurrence of each particle can also be specified. Like the data type, complexType can be derived from other types. The derivation method can be either restriction or extension. The derived type inherits the content of the base type plus corresponding modifications. In addition to inheritance, a type definition can make references to other components. This feature allows a component being defined once and used in many other structures. The type declaration and definition mechanism in XML Schema is much more flexible and powerful than the DTD.	Control by DTDs over the number of child elements in an element are assigned with the following symbols: ? = zero or one. In the foregoing DTD example, artist? implied artist is optional - there may or may not be an artist. * = zero or more + = one or more (in the foregoing DTD example, author+ implies more than one author is possible) (none) = exactly one
Identity Constraints XML Schema extends the concept of XML ID/IDREF mechanism with the declarations of unique, key and keyref. They are part of the type definition and allow not only attributes, but also element contents as keys. Each constraint has a scope within which it holds and the comparison is in terms of their value rather than lexical strings.
Import/Export Mechanisms (Schema Import, Inclusion and Modification) All components of a schema need not be defined in a single schema file. XML Schema provides a mechanism of assembling multiple schemas. Import is used to integrate schemas of different namespace while inclusion is used to add components of the same namespace. Components can also be modified using redefinition when included.	You cannot use constructs defined in external schemas.

XML Schema can be used to define a class of XML documents. "Instance document" describes an XML document that conforms to a particular schema.

Although these instances and schemas need not exist specifically as "documents", they are commonly referred to as files. They may exist as any of the following:

• Streams of bytes
• Fields in a database record
• Collections of XML Infoset "Information Items"

  See Also: http://www.w3.org/TR/xmlschema-0/ Appendix A, "XDK for Java: Specifications and Quick References" Oracle9i XML API Reference - XDK and Oracle XML DB

Oracle XML Schema Processor for Java Features

Oracle XML Schema Processor for Java has the following features:

• Supports streaming (SAX) precessing, constant memory usage, and linear processing time.
• Built on the Oracle XML Parser for Java v2
• Fully supports the W3C XML Schema specifications of the Candidate Recommendation (October 24, 2000) and the Recommendation (May 2, 2001).
  • XML Schema Part 0: Primer
  • XML Schema Part 1: Structures
  • XML Schema Part 2: Datatypes

Supported Character Sets

XML Schema Processor for Java supports documents in the following encodings:

• BIG
• EBCDIC-CP-*
• EUC-JP
• EUC-KR
• GB2312
• ISO-2022-JP
• ISO-2022-KR
• ISO-8859-1to -9
• ISO-10646-UCS-2
• ISO-10646-UCS-4
• KOI8-R
• Shift_JIS
• US-ASCII
• UTF-8
• UTF-16

What's Needed to Run XML Schema Processor for Java

To run XML Schema Processor for Java, you need the following:

• Operating Systems: Any OS with Java 1.1.x support
• Java: JDK 1.1.x. or above.

Online Documentation

Documentation for Oracle XML Schema Processor for Java is located in the doc/ directory in your install area.

Release Specific Notes

The readme.html file in the root directory of the archive, contains release specific information including bug fixes, and API additions.

Oracle XML Schema Processor is an early adopter release and is written in Java. It includes the production release of the XML Parser for Java v2.

XML Schema Processor for Java Directory Structure

Table 6-2 lists the directory structure after installing XML Schema Processor for Java.

Table 6-2 Directory Structure for an Installation of XML Schema Processor

Directory and File	Description
license.html	copy of license agreement
readme.html	release and installation notes
doc	directory for documents
lib	directory for class files
sample	directory for sample code files

XML Schema Processor for Java Usage

As shown in Figure 6-1, Oracle's XML Schema processor performs two major tasks:

• A builder assembles schema from schema XML documents
• A validator use the schema to validate instance document.

When building the schema, the builder first calls the DOM Parser to parse the schema XML documents into corresponding DOM trees. It then compiles them into an internal schema object. The validator works as a filter between the SAX parser and your applications for the instance document. The validator takes SAX events of the instance document as input and validates them against the schema. If the validator detects any invalid XML component it sends an error message. The output of the validator is:

• Input SAX events
• Default values it supplies
• Post-Schema Validation (PSV) information

Modes for Schema Validation

The XML Parser supports various modes for schema or DTD validation. The setValidationMode method allows different validation parameters to be set. For schema validations, there are these modes available:

• SCHEMA_VALIDATION. With this mode, the schema validator locates and builds schemas and validates the whole or a part of the instance document based on the schemaLocation and noNamespaceSchemaLocation attributes. See code example XSDSample.java.
• SCHEMA_LAX_VALIDATION. The validator tries to validate part or all of the instance document as long as it can find the schema definition. It will not raise an error if it cannot find the definition. See code example XSDLax.java.
• SCHEMA_STRICT_VALIDATION. The validator tries to validate the whole instance document, raising errors if it cannot find the schema definition or if the instance does not conform to the definition.

In addition to the validator to build the schema itself, you can use XSDBuilder to build schemas and set it to the validator using setXMLSchema method. See code example XSDSetSchema.java. By using the setXMLSchema method, the validation mode is automatically set to SCHEMA_STRICT_VALIDATION, and both schemaLocation and noNamespaceSchemaLocation attributes are ignored. You can also change the validation mode to SCHEMA_LAX_VALIDATION.

Using the XML Schema API

The API of the XML Schema Processor for Java is simple. You can either use either of the following:

• setSchemaValidationMode() in the DOMParser as shown in "XML Schema for Java Example 7: XSDSample.java"
• Explicitly build the schema using XSDBuilder and set the schema for XMLParser as shown in"XML Schema for Java Example 8: XSDSetSchema.java".

There is no clean-up call similar to xmlclean. If you need to release all memory and reset the state before validating a new XML document, terminate the context and start over.

Figure 6-1 XML Schema Processor for Java Usage

Text description of the illustration adxml105.gif

How to Run the XML Schema for Java Sample Program

XML Schema Processor for Java directory sample contains sample XML applications that illustrate how to use Oracle XML parser with XML Schema Processor for Java. Here are excerpts from the README file:

The sample Java files provided in this directory are:

XSDSample, a sample driver that processes XML instance documents.

XSDSetSchema, a sample driver to process XML instance documents by overriding the schemaLocation.

XSDLax, based on XSDSetSchema, but uses lax validation mode.

To run the sample program:

1. Execute the program make to generate .class files.
2. Add xmlparserv2.jar, xschema.jar, and the current directory to the CLASSPATH.
3. Run the sample program with the *.xml files:

   java XSDSample report.xml
   java XSDSetSchema report.xsd report.xml
   java XSDLax embeded_xsql.xsd embeded_xsql.xml
   
   

   XML Schema Processor uses the XML Schema specification from report.xsd to validate the contents of report.xml.

4. Run the sample program with the catalogue.xml file, as follows:

   java XSDSample   catalogue.xml
   java XSDSetSchema cat.xsd  catalogue.xml
   
   

   XML Schema Processor uses the XML Schema specification from cat.xsd to validate the contents of catalogue.xml.

5. The following are examples with XML Schema errors:

   java XSDSample catalogue_e.xml
   java XSDSample report_e.xml
   

Makefile for XML Schema Processor for Java

This is the file Makefile:

# Makefile for sample java files
#
# If not installed in ORACLE_HOME, set ORACLE_HOME to installation root
#
# ======================================================================

.SUFFIXES : .java .class

CLASSES = XSDSample.class XSDSetSchema.class XSDLax.class

# Change it to the appropriate separator based on the OS.
PATHSEP = :

# Assumes that the CLASSPATH contains JDK classes.
MAKE_CLASSPATH = 
.$(PATHSEP)$(ORACLE_HOME)/lib/xmlparserv2.jar$(PATHSEP)$(ORACLE_HOME)/lib/xschem
a.jar$(PATHSEP)$(CLASSPATH)

.java.class:
  @javac -classpath "$(MAKE_CLASSPATH)" $<

# make all class files
all: $(CLASSES)

demo:     $(CLASSES)
  @java -classpath "$(MAKE_CLASSPATH)" XSDSample report.xml > report.out
  @java -classpath "$(MAKE_CLASSPATH)" XSDSetSchema report.xsd report.xml > 
report.out 
  @java -classpath "$(MAKE_CLASSPATH)" XSDSample catalogue.xml > catalogue.out
  @java -classpath "$(MAKE_CLASSPATH)" XSDSetSchema cat.xsd catalogue.xml > 
catalogue.out 

  @java -classpath "$(MAKE_CLASSPATH)" XSDSample catalogue_e.xml > catalogue_e.out
  @java -classpath "$(MAKE_CLASSPATH)" XSDSample report_e.xml > report_e.out 

  @java -classpath "$(MAKE_CLASSPATH)" XSDLax embeded_xsql.xsd embeded_xsql.xml> 
embeded_xsql.out 

clean:    
  @rm -f *.class
  @rm -f *.out

XML Schema for Java Example 1: cat.xsd

This is the sample XML Schema Definition file that supplies input to the XSDSetSchema.java program. XML Schema Processor uses the XML Schema specification from cat.xsd to validate the contents of catalogue.xml.

<?xml version="1.0"?>
<schema xmlns="http://www.w3.org/2000/10/XMLSchema"
        targetNamespace="http://www.publishing.org/namespaces/Catalogue"
        elementFormDefault="qualified"
        xmlns:xsi="http://www.w3.org/1999/XMLSchema-instance"
        xmlns:cat="http://www.publishing.org/namespaces/Catalogue">

    <complexType name="PublicationType">
        <sequence>
            <element name="Title" type="string" minOccurs="1" 
maxOccurs="unbounded"/>
            <element name="Author" type="string" minOccurs="1" 
maxOccurs="unbounded"/>
            <element name="Date" type="year" minOccurs="1" maxOccurs="1"/>
        </sequence>
    </complexType>
    <element name="Publication" type="cat:PublicationType" abstract="true"/>
    <element name="Book" substitutionGroup="cat:Publication">
        <complexType>
          <complexContent>
            <extension base="cat:PublicationType">
               <sequence>
                  <element name="ISBN" type="string" minOccurs="1" 
maxOccurs="1"/>
                  <element name="Publisher" type="string" minOccurs="1" 
maxOccurs="1"/>
               </sequence>
            </extension>
          </complexContent>
        </complexType>
    </element>
    <element name="Magazine" substitutionGroup="cat:Publication">
        <complexType>
          <complexContent>
             <restriction base="cat:PublicationType">
               <sequence>
                  <element name="Title" type="string" minOccurs="1" 
maxOccurs="unbounded"/>
                  <element name="Author" type="string" minOccurs="0" 
maxOccurs="0"/>
                  <element name="Date" type="year" minOccurs="1" maxOccurs="1"/>
            </sequence>
           </restriction>
         </complexContent>
        </complexType>
    </element>
    <element name="Catalogue">
        <complexType>
            <sequence>
                <element ref="cat:Publication" minOccurs="0" 
maxOccurs="unbounded"/>
            </sequence>
        </complexType>
    </element>
</schema>

XML Schema for Java Example 2: catalogue.xml

This is the sample XML file that is validated by XML Schema processor against the XML Schema Definition file, cat.xsd, using the program, XSDSetSchema.java.

<?xml version="1.0"?>
<Catalogue xmlns="http://www.publishing.org/namespaces/Catalogue"
           xmlns:xsi="http://www.w3.org/2000/10/XMLSchema-instance"
           xsi:schemaLocation=
                      "http://www.publishing.org/namespaces/Catalogue
                       cat.xsd">
        <Magazine>
                <Title>Natural Health</Title>
                <Date>1999</Date>
        </Magazine>
        <Book>
                <Title>Illusions The Adventures of a Reluctant Messiah</Title>
                <Author>Richard Bach</Author>
                <Date>1977</Date>
                <ISBN>0-440-34319-4</ISBN>
                <Publisher>Dell Publishing Co.</Publisher>
        </Book>
        <Book>
                <Title>The First and Last Freedom</Title>
                <Author>J. Krishnamurti</Author>
                <Date>1954</Date>
                <ISBN>0-06-064831-7</ISBN>
                <Publisher>Harper &amp; Row</Publisher>
        </Book>
</Catalogue>

XML Schema for Java Example 3: catalogue_e.xml

When XML Schema Processor processes this sample XML file using XSDSample.java, it generates XML Schema errors.

<?xml version="1.0"?>
<Catalogue xmlns="http://www.publishing.org/namespaces/Catalogue"
           xmlns:xsi="http://www.w3.org/2000/10/XMLSchema-instance"
           xsi:schemaLocation=
                      "http://www.publishing.org/namespaces/Catalogue
                       cat.xsd">
        <Magazine>
                <Title>Natural Health</Title>
                <Date>1999</Date>
        </Magazine>
        <Book>
                <Title>Illusions The Adventures of a Reluctant Messiah</Title>
                <Author>Richard Bach</Author>
                <Date>July 7, 1977</Date>
                <ISBN>0-440-34319-4</ISBN>
                <Publisher>Dell Publishing Co.</Publisher>
        </Book>
        <Book>
                <Title>The First and Last Freedom</Title>
                <Author>J. Krishnamurti</Author>
                <Date>1954</Date>
                <ISBN>0-06-064831-7</ISBN>
                <ISBN>0-06-064831-7</ISBN>
                <Publisher>Harper &amp; Row</Publisher>
        </Book>
</Catalogue>

XML Schema for Java Example 4: report.xml

This is the sample XML file that is validated by XML Schema processor against the XML Schema Definition file, report.xsd, using the program, XSDSetSchema.java.

<purchaseReport
  xmlns="http://www.example.com/Report"
  xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.example.com/Report  report.xsd"
  period="P3M" periodEnding="1999-12-31">

 <regions>
  <zip code="95819">
   <part number="872-AA" quantity="1"/>
   <part number="926-AA" quantity="1"/>
   <part number="833-AA" quantity="1"/>
   <part number="455-BX" quantity="1"/>
  </zip>
  <zip code="63143">
   <part number="455-BX" quantity="4"/>
  </zip>
 </regions>

 <parts>
  <part number="872-AA">Lawnmower</part>
  <part number="926-AA">Baby Monitor</part>
  <part number="833-AA">Lapis Necklace</part>
  <part number="455-BX">Sturdy Shelves</part>
 </parts>

</purchaseReport>

XML Schema for Java Example 5: report.xsd

This is the sample XML Schema Definition file that inputs XSDSetSchema.java program. XML Schema Processor uses the XML Schema specification from report.xsd to validate the contents of report.xml.

<schema targetNamespace="http://www.example.com/Report"
        xmlns="http://www.w3.org/2001/XMLSchema"
        xmlns:r="http://www.example.com/Report"
        elementFormDefault="qualified">

 <annotation>
  <documentation xml:lang="en">
   Report schema for Example.com
   Copyright 2000 Example.com. All rights reserved.
  </documentation> 
 </annotation>

 <element name="purchaseReport">
  <complexType>
   <sequence>
    <element name="regions" type="r:RegionsType">
     <keyref name="dummy2" refer="r:pNumKey">
      <selector xpath="r:zip/r:part"/>
      <field xpath="@number"/>
     </keyref>
    </element>

    <element name="parts" type="r:PartsType"/>
   </sequence>
   <attribute name="period"       type="duration"/>
   <attribute name="periodEnding" type="date"/>
  </complexType>
  
  <unique name="dummy1">
   <selector xpath="r:regions/r:zip"/>
   <field xpath="@code"/>
  </unique>

  <key name="pNumKey">
   <selector xpath="r:parts/r:part"/>
   <field xpath="@number"/>
  </key>
 </element>

 <complexType name="RegionsType">
  <sequence>
   <element name="zip" maxOccurs="unbounded">
    <complexType>
     <sequence>
      <element name="part" maxOccurs="unbounded">
       <complexType>
        <complexContent>
         <restriction base="anyType">
          <attribute name="number"   type="r:SKU"/>
          <attribute name="quantity" type="positiveInteger"/>
         </restriction>
        </complexContent>
       </complexType>
      </element>
     </sequence>
     <attribute name="code" type="positiveInteger"/>
    </complexType>
   </element>
  </sequence>
 </complexType>
 <simpleType name="SKU">
  <restriction base="string">
   <pattern value="+{3}-[A-Z]{2}"/>
  </restriction>
 </simpleType>
 <complexType name="PartsType">
  <sequence>
   <element name="part" maxOccurs="unbounded">
    <complexType>
     <simpleContent>
      <extension base="string">
       <attribute name="number" type="r:SKU"/>
      </extension>
     </simpleContent>
    </complexType>
   </element>
  </sequence>
 </complexType>
</schema>

XML Schema for Java Example 6: report_e.xml

When XML Schema Processor processes this sample XML file using XSDSample.java, it generates XML Schema errors.

<purchaseReport
  xmlns="http://www.example.com/Report"
  xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.example.com/Report  report.xsd"
  period="P3M" periodEnding="1999-11-31">

 <regions>
  <zip code="95819">
   <part number="872-AA" quantity="1"/>
   <part number="926-AA" quantity="1"/>
   <part number="833-AA" quantity="1"/>
   <part number="455-BX" quantity="1"/>
  </zip>
  <zip code="63143">
   <part number="455-BX" quantity="4"/>
   <part number="235-JD" quantity="3"/>
  </zip>
 </regions>

 <parts>
  <part number="872-AA">Lawnmower</part>
  <part number="926-AA">Baby Monitor</part>
  <part number="833-AA">Lapis Necklace</part>
  <part number="455-BX">Sturdy Shelves</part>
 </parts>

</purchaseReport>

XML Schema for Java Example 7: XSDSample.java

//import oracle.xml.parser.schema.*;
import oracle.xml.parser.v2.*;

import java.net.*;
import java.io.*;
import org.w3c.dom.*;
import java.util.*;

public class XSDSample 
{
   public static void main(String[] args) throws Exception 
   {
      if (args.length != 1)
      {
         System.out.println("Usage: java XSDSample <filename>");
         return;
      }
      process (args[0]);
   }
   
   public static void process (String xmlURI) throws Exception 
   {
      
      DOMParser dp  = new DOMParser();
      URL       url = createURL (xmlURI);
      
      // Set Schema Validation to true
      dp.setValidationMode(XMLParser.SCHEMA_VALIDATION);
      dp.setPreserveWhitespace (true);
      
      dp.setErrorStream (System.out);
      
      try 
      {
         System.out.println("Parsing "+xmlURI);
         dp.parse (url);
         System.out.println("The input file <"+xmlURI+"> parsed without 
errors");
      } 
      catch (XMLParseException pe) 
      {
         System.out.println("Parser Exception: " + pe.getMessage());
      }
      catch (Exception e) 
      { 
         System.out.println("NonParserException: " + e.getMessage()); 
      }

  }

   // Helper method to create a URL from a file name
   static URL createURL(String fileName)
   {
      URL url = null;
      try
      {
         url = new URL(fileName);
      }
      catch (MalformedURLException ex)
      {
         File f = new File(fileName);
         try
         {
            String path = f.getAbsolutePath();
            // This is a bunch of weird code that is required to
            // make a valid URL on the Windows platform, due
            // to inconsistencies in what getAbsolutePath returns.
            String fs = System.getProperty("file.separator");
            if (fs.length() == 1)
            {
               char sep = fs.charAt(0);
               if (sep != '/')
                  path = path.replace(sep, '/');
               if (path.charAt(0) != '/')
                  path = '/' + path;
            }
            path = "file://" + path;
            url = new URL(path);
         }
         catch (MalformedURLException e)
         {
            System.out.println("Cannot create url for: " + fileName);
            System.exit(0);
         }
      }
      return url;
   }

}

XML Schema for Java Example 8: XSDSetSchema.java

When this example is run with cat.xsd and catalogue.xml, XML Schema Processor uses the XML Schema specification from cat.xsd to validate the contents of catalogue.xml.

When this example is run with report.xsd and report.xml, XML Schema Processor uses the XML Schema specification from cat.xsd to validate the contents of report.xml.

import oracle.xml.parser.schema.*;
import oracle.xml.parser.v2.*;

import java.net.*;
import java.io.*;
import org.w3c.dom.*;
import java.util.*;

public class XSDSetSchema
{
   public static void main(String[] args) throws Exception 
   {
      if (args.length != 2)
      {
         System.out.println("Usage: java XSDSample <schema_file> <xml_file>");
         return;
      }

      XSDBuilder builder = new XSDBuilder();
      URL    url =  createURL(args[0]);       

      // Build XML Schema Object
      XMLSchema schemadoc = (XMLSchema)builder.build(url);      
      process(args[1], schemadoc);
   }

   public static void process(String xmlURI, XMLSchema schemadoc) 
   throws Exception 
   {
      
      DOMParser dp  = new DOMParser();
      URL       url = createURL (xmlURI);
      
      // Set Schema Object for Validation
      dp.setXMLSchema(schemadoc);
      dp.setValidationMode(XMLParser.SCHEMA_VALIDATION);
      dp.setPreserveWhitespace (true);
      
      dp.setErrorStream (System.out);
      
      try 
      {
         System.out.println("Parsing "+xmlURI);
         dp.parse (url);
         System.out.println("The input file <"+xmlURI+"> parsed without 
errors");
      }
      catch (XMLParseException pe) 
      {
         System.out.println("Parser Exception: " + pe.getMessage());
      }
      catch (Exception e) 
      { 
         System.out.println ("NonParserException: " + e.getMessage()); 
      }
      
   }

   // Helper method to create a URL from a file name
   static URL createURL(String fileName)
   {
      URL url = null;
      try
      {
         url = new URL(fileName);
      }
      catch (MalformedURLException ex)
      {
         File f = new File(fileName);
         try
         {
            String path = f.getAbsolutePath();
            // This is a bunch of weird code that is required to
            // make a valid URL on the Windows platform, due
            // to inconsistencies in what getAbsolutePath returns.
            String fs = System.getProperty("file.separator");
            if (fs.length() == 1)
            {
               char sep = fs.charAt(0);
               if (sep != '/')
                  path = path.replace(sep, '/');
               if (path.charAt(0) != '/')
                  path = '/' + path;
            }
            path = "file://" + path;
            url = new URL(path);
         }
         catch (MalformedURLException e)
         {
            System.out.println("Cannot create url for: " + fileName);
            System.exit(0);
         }
      }
      return url;
   }

}

XML Schema for Java Example 9: XSDLax.java

Here is a listing of XSDLax.java:

import oracle.xml.parser.schema.*;
import oracle.xml.parser.v2.*;

import java.net.*;
import java.io.*;
import org.w3c.dom.*;
import java.util.*;

public class XSDLax
{
   public static void main(String[] args) throws Exception 
   {
      if (args.length != 2)
      {
         System.out.println("Usage: java XSDSample <schema_file> <xml_file>");
         return;
      }

      XSDBuilder builder = new XSDBuilder();
      URL    url =  createURL(args[0]);       

      // Build XML Schema Object
      XMLSchema schemadoc = (XMLSchema)builder.build(url);      
      process(args[1], schemadoc);
   }

   public static void process(String xmlURI, XMLSchema schemadoc) 
   throws Exception 
   {
      
      DOMParser dp  = new DOMParser();
      URL       url = createURL (xmlURI);
      
      // Set Schema Object for Validation
      dp.setXMLSchema(schemadoc);
      dp.setValidationMode(XMLParser.SCHEMA_LAX_VALIDATION);
      dp.setPreserveWhitespace (true);
      
      dp.setErrorStream (System.out);
      
      try 
      {
         System.out.println("Parsing "+xmlURI);
         dp.parse (url);
         System.out.println("The input file <"+xmlURI+"> parsed without 
errors");
      }
      catch (XMLParseException pe) 
      {
         System.out.println("Parser Exception: " + pe.getMessage());
      }
      catch (Exception e) 
      { 
         System.out.println ("NonParserException: " + e.getMessage()); 
      }
      
   }

   // Helper method to create a URL from a file name
   static URL createURL(String fileName)
   {
      URL url = null;
      try
      {
         url = new URL(fileName);
      }
      catch (MalformedURLException ex)
      {
         File f = new File(fileName);
         try
         {
            String path = f.getAbsolutePath();
            // This is a bunch of weird code that is required to
            // make a valid URL on the Windows platform, due
            // to inconsistencies in what getAbsolutePath returns.
            String fs = System.getProperty("file.separator");
            if (fs.length() == 1)
            {
               char sep = fs.charAt(0);
               if (sep != '/')
                  path = path.replace(sep, '/');
               if (path.charAt(0) != '/')
                  path = '/' + path;
            }
            path = "file://" + path;
            url = new URL(path);
         }
         catch (MalformedURLException e)
         {
            System.out.println("Cannot create url for: " + fileName);
            System.exit(0);
         }
      }
      return url;
   }

}

XML Schema for Java Example 10: embeded_xsql.xsd

This is the input file for XSDLax.java:

<?xml version="1.0" encoding="ISO-8859-1"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
            xmlns = "http://xmlns.us.oracle.com/XDK/Example/XSQL/schema"
            targetNamespace = 
"http://xmlns.us.oracle.com/XDK/Example/XSQL/schema"
            elementFormDefault="qualified">

<xsd:element name="include-xml">
  <xsd:complexType>
     <xsd:simpleContent>
       <xsd:extension base="xsd:string">
          <xsd:attribute name="href" type="xsd:string"/>
       </xsd:extension>
     </xsd:simpleContent>
  </xsd:complexType>
</xsd:element>

<xsd:simpleType name="XSQLBool">
  <xsd:restriction base="xsd:string">
    <xsd:enumeration value="yes"/>
    <xsd:enumeration value="no"/>
  </xsd:restriction>
</xsd:simpleType>

<xsd:simpleType name="XSQLTagCase">
  <xsd:restriction base="xsd:string">
    <xsd:enumeration value="lower"/>
    <xsd:enumeration value="upper"/>
  </xsd:restriction>
</xsd:simpleType>

<xsd:element name="query">
  <xsd:complexType>
   <xsd:simpleContent>
    <xsd:extension base="xsd:string">
     <xsd:attribute name="bind-params" type="xsd:string"/>
     <xsd:attribute name="date-format" type="xsd:string"/>
     <xsd:attribute name="error-statement" type="XSQLBool"/>
     <xsd:attribute name="fetch-size" type="xsd:positiveInteger"/>
     <xsd:attribute name="id-attribute" type="xsd:string"/>
     <xsd:attribute name="id-attribute-column" type="xsd:string"/>
     <xsd:attribute name="include-schema" type="XSQLBool"/>
     <xsd:attribute name="max-rows" type="xsd:positiveInteger"/>
     <xsd:attribute name="null-indicator" type="XSQLBool"/>
     <xsd:attribute name="rowset-element" type="xsd:string"/>
     <xsd:attribute name="row-element" type="xsd:string"/>
     <xsd:attribute name="skip-rows" type="xsd:positiveInteger"/>
     <xsd:attribute name="tag-case" type="XSQLTagCase"/>
    </xsd:extension>
   </xsd:simpleContent>
  </xsd:complexType>
</xsd:element>

</xsd:schema>

XML Schema for Java Example 11: embeded_xsql.xml

Here is the output file from XSDLax.java:

<?xml version="1.0" ?> 
<page connection="xdkdemo" 
xmlns:xsql="http://xmlns.us.oracle.com/XDK/Example/XSQL/
schema">
  <webpage title=" Search for XDK FAQ">
      <search>
       <xsql:include-xml href="xml/title.xml" /> 
      </search>
          <content>
            <question>
              <xsql:query fetch-size="50" null-indicator="no">
                     select question from xdkfaq 
                     where contains(answer,'{@search}')>0
                   </xsql:query>
                </question>
                <time>
              <xsql:query tag-case="lower" max-rows="20">
                     select to_char(sysdate,'DD-MM-YYY') from dual
                   </xsql:query>
                </time>
          </content>
  </webpage>
</page>