::::::::::::::
exp.xsd
::::::::::::::
<xsd:schema xmlns:xsd="http://www.w3.org/2000/10/XMLSchema">

<xsd:element name="container" type="Exp"/>

<xsd:complexType name="Exp">
  <xsd:sequence>
    <xsd:element name="expression" type="E"/>
  </xsd:sequence>
</xsd:complexType>

<xsd:complexType name="E" abstract="true">
  <xsd:sequence>
    <xsd:element name="depth" type="xsd:positiveInteger" minOccurs="0"/>
  </xsd:sequence>
</xsd:complexType>

<xsd:complexType name="S">
  <xsd:complexContent>
    <xsd:extension base="E">
      <xsd:sequence>
        <xsd:element name="value" type="xsd:int"/>
      </xsd:sequence>
    </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

<xsd:complexType name="C">
  <xsd:complexContent>
    <xsd:extension base="E">
      <xsd:sequence>
        <xsd:element name="op" type="Op"/>
        <xsd:element name="args" type="Exp" minOccurs="0" maxOccurs="unbounded"/>
      </xsd:sequence>
    </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

<xsd:simpleType name="Op">
  <xsd:restriction base="xsd:string">
    <xsd:enumeration value="+"/>
    <xsd:enumeration value="*"/>
  </xsd:restriction>
</xsd:simpleType>

</xsd:schema>


::::::::::::::
exp/X2J.cd
::::::::::::::
import java.util.*;
import java.io.*;


// *************************************************************************
// The following section has been generated automatically by the XML to Java
// conversion application.
// *************************************************************************

XMLDoc		= "<?xml"
		  "version" "=" <version> String
		  [ "encoding" "=" <encoding> String ]
		   "?>"
		  "<container"
		  [ "xsi" "=" <schemaInstanceURL> String ]
		  [ "schemaLocation" "=" <schemaLoc> String ]
		  [ "noNamespaceSchemaLocation" "=" <schemaLocNoNS> String ]
		  <container> Exp "</container>".

Exp		= ">"
		  "<expression" <expression> E "</expression>".

E		: lookahead {{3}} S | lookahead {{3}} C.

XMLpositiveInteger = <value> int.

S		= "type" "=" "S"
		  ">"
		  [ "<depth>" <depth> XMLpositiveInteger "</depth>" ]
		  "<value>" <value> int "</value>".

C		= "type" "=" "C"
		  ">"
		  [ "<depth>" <depth> XMLpositiveInteger "</depth>" ]
		  "<op>" <op> Op "</op>"
		  <argsListUnit> List(argsListUnit).

argsListUnit	= "<args" <args> Exp "</args>".

Op		= <value> String.


Main		= .
Preprocessor	= .

List(S)		~ {S}.

visitor ValidateVisitor = .

// *************************************************************************
// End of automatically generated section.
// *************************************************************************


::::::::::::::
exp/X2Jdoc.beh
::::::::::::::
XMLDoc {

    public static XMLDoc XMLparse(String in) throws Exception {{
        XMLDoc doc = parse(Preprocessor.process(in));
        String errors = doc.validate();
        if (!errors.equals(""))
            throw new ParseException(errors);
        return doc;
    }}

    public static XMLDoc XMLparse(InputStream in) throws Exception {{
        return XMLparse(Preprocessor.process(readContent(in)));
    }}

    public static XMLDoc XMLparse(Reader in) throws Exception {{
        return XMLparse(Preprocessor.process(readContent(in)));
    }}

    private static String readContent(InputStream in) throws Exception {{
        String text = "";
        try {
            byte buf[] = new byte[1000];
            while (true)
            {
                int size = in.read(buf);
                if (size <= 0) break;
                String line = new String(buf, 0, size);
                if (!text.equals("")) text = text + "\n";
                text = text + line;
            }
            in.close();
            return text;
        }
        catch (IOException e) {
            throw new Exception("Error in reading input");
        }
    }}

    private static String readContent(Reader in) throws Exception {{
        BufferedReader r = new BufferedReader(in);
        String text = "";
        try {
            while (true)
            {
                String line = r.readLine();
                if (line == null) break;
                if (!text.equals("")) text = text + "\n";
                text = text + line;
            }
            r.close();
            return text;
        }
        catch (IOException e) {
            throw new Exception("Error in reading input");
        }
    }}


    public String validate() bypassing -> *,tail,* to * (ValidateVisitor);

}  // end of class XMLDoc


::::::::::::::
exp/X2Jpreprocessor.beh
::::::::::::::
Preprocessor {

    public static String process(String in) {{
        return in;
    }}

}  // end of class Preprocessor


::::::::::::::
exp/X2Jvalidate.beh
::::::::::::::
ValidateVisitor {

    {{
    private String errors = "";
    }}

    before S {{
        if (host.get_depth() != null && host.get_depth().get_value() < 1)
            addError("Value (" + host.get_depth().get_value() + ") of element 'depth' is < 1");
    }}

    before C {{
        if (host.get_depth() != null && host.get_depth().get_value() < 1)
            addError("Value (" + host.get_depth().get_value() + ") of element 'depth' is < 1");
        if (host.get_op() != null && new String("
+
*").indexOf("
" + host.get_op().get_value() + "") < 0)
            addError("Value (" + host.get_op().get_value() + ") of element 'op' is not one of the enumerated values");
    }}

    public String get_return_val() {{
        return errors;
    }}

    private void addError(String errorText) {{
        errors = errors + "\n" + errorText;
    }}

}  // end of class ValidateVisitor


::::::::::::::
exp/exp.beh
::::::::::::::
Main {
  public static void main(String args[]) throws Exception {{
    XMLDoc d = XMLDoc.XMLparse(System.in);

    d.print();
    System.out.println("");
  }}
}


XMLDoc {
  public void print() bypassing -> *,tail,* to * (DisplayVisitor);
}