Richfaces 3. How to custom sort in columns always displaying null values at the end

[siva999]

Hi All,

I'm using <rich:dataTable/> with some <rich:column/> columns.

The data I want to display contains some null values on a property.

Basically, the sort feature of <rich:column/> is to display those null values on the top or bottom of the list, depending on the current sort direction value.

I want to display those null values always on the bottom of the list.

Can I use a Comparator for sorting a column? If so ... are there any examples somewhere or more detailed documentation ?

Regards

[ilya_shaikovsky]

use comparator attribute. define your own comparator which will works as you need.

[siva999]

Thanks Ilya. To test I tried to use my own comparator, a simple one to sort the dates in ascending order but it is not working. I am not sure what i am doing wrong here.

<rich:dataTable id="tableId" var="_cmpts" value="#{cmptBean.cmptList}">

<rich:column id="cpmtName"   sortBy="#{_cmpts.name}"    sortable="true">
    <f:facet name="header">   <h:outputText value="Name"/>  </f:facet>
    <h:outputText value="#{_cmpts.name}" />
</rich:column>
  

<rich:column id="startDate" sortBy="#{_cmpts.startDate}"  sortable="true"  sortOrder="#{sortBean.startDateOrder}"      

      comparator="#{sortBean.startDateComparator}">
   <f:facet name="header"> <h:outputText value="Start Date"/> </f:facet>
   <h:outputText value="#{cmpts.startDate}" />
</rich:column>

</rich:dataTable>

public class SortBean implements Serializable {
   
     private static final long serialVersionUID = 1L;
     public SortBean() {
     }
    
     private Ordering startDateOrder = Ordering.ASCENDING;
    
     public Ordering getStartDateOrder() {
      return startDateOrder;
     }
   
     public void setStartDateOrder(Ordering startDateOrder) {
      this.startDateOrder = startDateOrder;
     }
   
     public Comparator<Cmpt> getStartDateComparator(){
      return new Comparator<Cmpt>() {
             public int compare(Cmpt c1, Cmpt c2) {

              return c1.getStartDate().compareTo(c2.getStartDate());
             }
      };
     }
     
}

When i debug i can observe that getStartDateComparator() is being called.

[lilyju]

Hi Siva,

Did you end up solving your issue? I use <rich:column comparator, but it does not sort when I click the column.

Thanks,

Lily

[brc]

Hi all,

I got similar issue where I needed to implement custom coparator class and did everything like Siva, except part:

   public Comparator<Cmpt> getStartDateComparator(){

      return new Comparator<Cmpt>() {

             public int compare(Cmpt c1, Cmpt c2) {             

             return c1.getStartDate().compareTo(c2.getStartDate());

             }

      };

     }

this inner class was problematic, so I created "normal" comparator class like this:

public class NameColumnComparator implements Comparator<CustomerListItem>{

    public int compare(CustomerListItem c1, CustomerListItem c2){

          return c1.getCustomerCompleteName().compareToIgnoreCase(c2.getCustomerCompleteName());

    }

}

and call my new comparator from frontend exposed class like this:

public someClass implements Serialazible {

private static final long serialVersionUID = -1L;

private NameColumnComparator nameComparator = new NameColumnComparator();

public Comparator<CustomerListItem> getNameComparator(){

        return nameComparator;

    }

}

I hope this solves a problem...