Prerequisites

You may find usefull to configure your environnment by using an alias, so that the command of this tutorial appears simpler.
The following definition is for Bash shell:

alias drb='java -jar [DRB_INSTALLATION_HOME]/lib/java/drb-[M]-[m]-[t].jar'

Working with xs:list

Case where the number of item in the list is fixed

Having the list.ascii :

LIST_OF_NUMBERS=1 145 -56 101

Note: We know that the number of items in this sample is always 4.

Having the list.xsd :

<?xml version="1.0" encoding="UTF-8"?>
 
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
           xmlns:sdf="http://www.gael.fr/2005/04/drb/sdf"
           elementFormDefault="qualified"
           attributeFormDefault="unqualified">
 
   <!-- Definition of the root node which contains all the content -->
   <xs:element name="Lists">
      <xs:complexType>
         <xs:annotation>
            <xs:appinfo>
               <sdf:block>
                  <sdf:encoding>ASCII</sdf:encoding>
               </sdf:block>
            </xs:appinfo>
         </xs:annotation>
         
         <xs:sequence>
 
            <xs:element name="ListOfNumbers" type="ListOfNumbersType">
               <xs:annotation>
                  <xs:documentation xml:lang="en">
                  </xs:documentation>
               </xs:annotation>
            </xs:element>

         </xs:sequence>
      </xs:complexType>
   </xs:element>

   <xs:simpleType name="ListOfNumbersType">
      <xs:annotation>
         <xs:documentation xml:lang="en">
         </xs:documentation>

         <xs:appinfo>
            <sdf:block>
               <sdf:encoding>ASCII</sdf:encoding>
               <sdf:padding type="header">16</sdf:padding>
               <sdf:delimiter>&#10;</sdf:delimiter>
               <sdf:array>
                  <sdf:occurrence>4</sdf:occurrence>   
               </sdf:array>
            </sdf:block>
         </xs:appinfo>
      </xs:annotation>
      
      <xs:list itemType="xs:integer"/>
   </xs:simpleType>

</xs:schema>

The main point is the sdf:occurrence markup which is set to the fixed value: "4", since there is always 4 items in our data file.

Case where the number of item in the list is not fixed

In this particular case two situations can occurs:

• Case where the occurrence can be retrieve from another field in the data file :
  Having the list2.ascii :

  NB_NUMBERS=4
  LIST_OF_NUMBERS=1 145 -56 101

  Note that the first entry (NB_NUMBERS) in the file indicate the number of values in the second field.

  Having the list2.xsd :

  <?xml version="1.0" encoding="UTF-8"?>
   
  <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
             xmlns:sdf="http://www.gael.fr/2005/04/drb/sdf"
             elementFormDefault="qualified"
             attributeFormDefault="unqualified">
   
     <!-- Definition of the root node which contains all the content -->
     <xs:element name="Lists">
        <xs:complexType>
           <xs:annotation>
              <xs:appinfo>
                 <sdf:block>
                    <sdf:encoding>ASCII</sdf:encoding>
                 </sdf:block>
              </xs:appinfo>
           </xs:annotation>
           
           <xs:sequence>
   
              <xs:element name="NbNumbers" type="NbNumbersType">
                 <xs:annotation>
                    <xs:documentation xml:lang="en">
                    </xs:documentation>
                 </xs:annotation>
              </xs:element>
  
              <xs:element name="ListOfNumbers" type="ListOfNumbersType">
                 <xs:annotation>
                    <xs:documentation xml:lang="en">
                    </xs:documentation>
                 </xs:annotation>
              </xs:element>
  
           </xs:sequence>
        </xs:complexType>
     </xs:element>
  
     <xs:simpleType name="NbNumbersType">
        <xs:annotation>
           <xs:documentation xml:lang="en">
           </xs:documentation>
  
           <xs:appinfo>
              <sdf:block>
                 <sdf:encoding>ASCII</sdf:encoding>
                 <sdf:padding type="header">11</sdf:padding>
                 <sdf:delimiter>&#10;</sdf:delimiter>
              </sdf:block>
           </xs:appinfo>
        </xs:annotation>
        
        <xs:restriction base="xs:int"/>
     </xs:simpleType>
  
     <xs:simpleType name="ListOfNumbersType">
        <xs:annotation>
           <xs:documentation xml:lang="en">
           </xs:documentation>
  
           <xs:appinfo>
              <sdf:block>
                 <sdf:encoding>ASCII</sdf:encoding>
                 <sdf:padding type="header">16</sdf:padding>
                 <sdf:delimiter>&#10;</sdf:delimiter>
                 <sdf:array>
                    <sdf:occurrence query="../NbNumbers"/>
                 </sdf:array>
              </sdf:block>
           </xs:appinfo>
        </xs:annotation>
        
        <xs:list itemType="xs:integer"/>
     </xs:simpleType>
  
  </xs:schema>

  Note how the query ../NbNumbers specify inside the sdf:occurrence markup is setted so that it retrieve the value read from the first entry NbNumbers.

• Case where the occurrence can't be known :
  This case is not yet supported by DRB APIŽ
  Nevetheless in some particular conditions: if the length of each element in the list and the size of the list are known, then DRB APIŽ is able to compute the occurrence number by itself.

Access a xs:list with query

For accessing a xs:list remember to use the fn:data() function.
Example:

drb -s "fn:data(list.ascii/(list.xsd)*/ListOfNumbers)[3]"

The previous command will return the third item in the list:

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