For most query types, the results property of the form handler is set to the Results object returned by ATG Search. Typically, you do not need to modify the Results object in the ATG platform, because ATG Search includes many configuration options for customizing the search results on the server side.
In some cases, however, you may want to manipulate or filter the data in some way on the client (ATG platform) side. To enable you to do this, each form handler has a resultsFetcher property that can point to a component that implements the atg.search.query.formhandlers.ResultsFetchingProxy interface. If the form handler is configured this way, the fetch() method of this component is used to get the Results object. Your implementation of this method can include logic that modifies the Results object before using it to set the results property of the form handler.
The ATG platform includes a class, atg.search.query.formhandlers.CollectionFilterFetchingProxy, that implements the ResultFetchingProxy interface. This class has a filter property that you can set to a collection filter component that performs the actual filtering of the results.
In addition, the ATG platform includes an abstract class for filtering results returned by ATG Search. This class, atg.search.query.filters.RepositoryItemResultCollectionFilter, serves as a base class that you can subclass to create your own collection filters.
The following example shows the source code of a sample subclass, atg.search.query.filters.SampleRepositoryItemCollectionFilter, which evaluates all of the Result objects stored in the results property of the Results object, and rejects any Result object that does not refer to a valid repository item. The SampleRepositoryItemCollectionFilter class is intended mainly as a simple example of how to write a collection filter that operates on an ATG Search Results object, and is not necessarily functionality that you will find useful in itself.
package atg.search.query.filters;
import atg.repository.Repository;
import atg.repository.RepositoryException;
import atg.repository.RepositoryItem;
import atg.service.collections.filter.FilterException;
import com.primus.searchstudio.Result;
import javax.naming.NamingException;
/**
* A sample RepositoryItemResultCollectionFilter which rejects any
* search Result object which does not refer to a valid repository
* item.
*/
public class SampleRepositoryItemCollectionFilter extends
RepositoryItemResultCollectionFilter
{
public SampleRepositoryItemCollectionFilter() {}
/**
* Filter that rejects any search result that does not refer to a
* repository item
*
* @param pResult a search result object
* @param pRepositoryItem the associated repository item or null if
* the search result object does not refer to a repository item
*/
protected boolean accept( Result pResult, RepositoryItem pUserProfile)
throws FilterException
{
RepositoryItem repositoryItem = null;
try {
// Use the url property of the Result object to retrieve the
// repository item
repositoryItem = getRepositoryItem( pResult );
}
catch ( NamingException ne ) {
// Don't care
}
if ( isLoggingDebug() )
logDebug( "repositoryItem = " + repositoryItem );
return repositoryItem != null;
}
}For more information about collection filters, see the ATG Personalization Programming Guide.
