Mashup API interface

/**
 * Feed Trigger interface: A Feed Trigger is an entry point to alter the
 * behavior of a Feed. It is called before and after the feed execution,
 * allowing for query manipulation, context modification and result
 * manipulation. IMPORTANT: Feed Triggers are shared across the request and thus
 * MUST be both stateless and threadsafe. If you need to keep states
 * between the beforeQuery call and the afterQuery call, you can store the
 * variables in the QueryContext:
 * beforeQuery: context.setVariable("myComputedScore", 42);
 * afterQuery: context.getVariable("myComputedScore");
 */
public interface FeedTrigger {
  /**
   * Before Feed Execution call. Return Result.STOP to skip the evaluation of
   * the feed, Result.CONTINUE for the normal behavior.
   * 
   * @param feed
   * @param context
   * @throws AccessException
   */
  public Result beforeQuery(Feed feed, QueryContext context) throws AccessException;
  /**
   * After Feed Execution call. Return Result.CONTINUE for the normal behavior,
   * or Result.EVAL_AGAIN to re-execute the feed after overriding a few
   * parameters.
   * 
   * @param feed
   * @param context
   * @throws AccessException
   */
  public Result afterQuery(Feed feed, QueryContext context, ResultFeed resultFeed) throws 
AccessException;

  public enum Result {
    CONTINUE,
    STOP,
    EVAL_AGAIN
  }
  /**
   * A Trigger that implements BeforeSubfeedAware will receive an additional event after its execute() 
method,
   * but before the sub feeds processing.
   */
  public static interface BeforeSubfeedAware {

    public Result beforeSubfeeds(Feed feed, QueryContext context, ResultFeed resultFeed) throws 
AccessException;

  }
}

The following Java snippet is an example of basic query rewriting, replacing all occurrences of the word "rain" by the word "sun".

package my.test;

import com.exalead.access.feedapi.AccessException;
import com.exalead.access.feedapi.Feed;
import com.exalead.access.feedapi.FeedTrigger;
import com.exalead.access.feedapi.QueryContext;
import com.exalead.access.feedapi.ResultFeed;

public class SampleTrigger implements FeedTrigger {

  public Result beforeQuery(Feed feed, QueryContext context) throws AccessException {
    // Fetches the original q parameter
    String originalQuery = feed.getEvaluatedParameter(context, "q");
    System.out.println("Original query: " + originalQuery);

    // Computes the new query
    String newQuery = originalQuery.replace("rain", "sun");
    System.out.println("New query:" + newQuery);

    // Forces the "q" parameter to the new query
    feed.overrideParameter(context, "q", newQuery);
    return Result.CONTINUE;
  }

  public Result afterQuery(Feed feed, QueryContext context, ResultFeed resultFeed) throws AccessException {
    return Result.CONTINUE;
  }

}
// To get your custom code running into your CloudView 360 instance, compile it into 
// a .jar file and drop it in the javabin directory of your CloudView 360 kit. 
// Finally, to plug your Trigger in the Access.xml configuration file, 
// just add a <Trigger> tag to the targeted feed:

<Feed id="bi" enable="true" embed="true" className="com.exalead.access.basefeeds.BusinessItemFeed">
  <Trigger className="my.test.SampleTrigger" />
  <Parameters>
    <Parameter name="searchAPIVersion">5.0</Parameter>
    <Parameter name="searchapi">{access-api.searchapi.url}/search</Parameter>
    <Parameter name="q">${page.params["q"]}</Parameter>
    <Parameter name="type">all</Parameter>
    <Parameter name="page">1</Parameter>
    <Parameter name="defaultQuery">all</Parameter>
    <Parameter name="per_page">10</Parameter>
  </Parameters>
</Feed>