Using default search values on the JHeadstart advanced search

When building ADF applications using JHeadstart, one can benefit from the pretty advanced search facilities provided by JHeadstart, both through its runtime framework and as generated by the JHeadstart ADF Application Generator. One thing however it does not do is provide support for default values for search items. That means: when I go to the search section for a certain group, by default one or more search items have a value, that the user then can stray from by overriding it. In this article I will briefly discuss how we can apply such default values.

 The JHeadstart search area is tied to an instance of the JhsSearchBean. It is this bean that holds the values of the search items as well as the list of query operators to apply to each of these values and also the methods that perform the search itself (by calling counterpart methods in the ApplicationModuleImpl). The fields in the search area have value attributes such as: value="#{searchDept.criteria.DeptLoc}", with searchDept the reference to the search bean configuration as managed bean.

We can extend from JhsSearchBean to add the support for default values for these search items:

package nl.cxs.jheadstart.controller;

import java.util.Iterator;
import java.util.Map;

import oracle.jheadstart.controller.jsf.bean.JhsSearchBean;


public class CxsJhsSearchBean extends JhsSearchBean {

    private Map defaultSearchValues;

    public CxsJhsSearchBean() {
    }

    public void applyDefaultSearchValue() {
        Iterator defaultSearchItems = getDefaultSearchValues().keySet().iterator();
        while (defaultSearchItems.hasNext())
        {
          String property = (String)defaultSearchItems.next();
          Object value = getDefaultSearchValues().get(property);
          super.getCriteria().put(property, value);
        }//while
    }

    public void setDefaultSearchValues(Map defaultSearchValues) {
        this.defaultSearchValues = defaultSearchValues;
    }

    public Map getDefaultSearchValues() {
        return defaultSearchValues;
    }
}
 

The property defaultSearchValues – a Map – holds the collection of propertyName=defaultValue pairs.

In the managed bean configuration of the search bean, we have to refer to our search bean instead of the standard JHeadstart search bean, and of course we have to provide default values for one or more of the search items – that was the whole point after all:

  <managed-bean>
    <managed-bean-name>searchDept</managed-bean-name>
    <managed-bean-class>nl.cxs.jheadstart.controller.CxsJhsSearchBean</managed-bean-class>
    <managed-bean-scope>session</managed-bean-scope>
    <managed-property>
      <property-name>bindings</property-name>
    ...
    <managed-property>
      <property-name>defaultSearchValues</property-name>
      <map-entries>
        <key-class>java.lang.String</key-class>
        <map-entry>
          <key>DeptLoc</key>
          <value>N%</value>
        </map-entry>
      </map-entries>
    </managed-property>
  </managed-bean>

We could extend the functionality easily to allow EL Expressions for values, rather than hard-coded values.

When to reset the search bean?

One important question not really addressed in JHeadstart is: when whould we clear the search bean? The search bean is a session-scope bean and after first initialization, it is never (automatically) reset. That means that when a user performs a search, navigates to a host of other pages and then returns to the page with the initial search form, the very same search criteria previously entered are still in effect. However, I can very well imagine that users would like to return to an empty – except for default values! – search form. That has yet to be provided. (for example using a InvokeMethodBean that resets the search criteria and reapplies the default search values  for the Start<GROUP> condition, configured on the JhsPageLifecycle).