validating an integer in an array

[Thomas Bailey]

Hi,
   
  I am struggling with something which must be simple - Ive spent a day or so 
going through examples but could not find anything covering this !
   
  I want to be able to fill an array of values in my form and use the validator 
to ensure they are all of type integer. I am using string arrays since I recall 
reading somewhere this is best practise and all the struts examples use string.
   
  I have a select box in a JSP which looks like:
   
  <html:select property="types"  multiple="true" size="3" >
<html:option value="1">should work</html:option>    
  <html:option value="2">should work as well</html:option> 
  <html:option value="blah">this will fail validation</html:option>       
  </html:select>
   
  my actionform looks like:
   
  public class PropertyFilter implements Serializable 
  {
  private String[] types;
 
    public String[] getTypes() {
    return types;
  }
    public void setTypes(String[] types) {
    this.types = types;
  }
  }
   
  my validation.xml
   
  <formset>
  <form name="PropertyFilterForm">
  
<field property="types" depends="integer">
<arg0 key="text.validation.type"/>
  </field>
   
  </form>
  </formset>
   
  Regardless what I fill, even if the values are integer, it fails to pass 
validation. According to 
http://www.strutskickstart.com/IndexedPropertiesandValidation.ppt#18  I should 
do something like:
   
  <field property="types" indexedListProperty="types" depends="integer">
<arg0 key="text.validation.type"/>
</field>
   
  This time, it does indeed check all the values are of type integer, however, 
if you do not select anything (the field is not required) the result is:
   
  java.lang.NullPointerException
org.apache.commons.validator.Field.getIndexedProperty(Field.java:796)
org.apache.commons.validator.Field.validate(Field.java:891)
  ..
   
  Is there an example showing exactly how this should be done anywhere ? - ive 
been through all the current and future struts release examples and found 
nothing that checks an integer specifically. Could someone comment on the above 
to where I am going wrong ?
   
  Thanks,
   
  Tom