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The OpenTripPlanner multimodal journey planning system

There is a newer version: 2.5.0

package org.opentripplanner.routing.algorithm.filterchain;

import org.opentripplanner.model.plan.Itinerary;

import java.util.List;

/**
 * Filter, sort or decorate itineraries. A filter can modify the elements in the list, but not the
 * List. It should treat the list as immutable. Do not change the list passed into the filter,
 * instead　make a copy, change it and return the copy. It is allowed to return the list unchanged.
 * 
 * A filter should do only one thing! For example do not change the itineraries and delete elements
 * in the same filter. Instead, create two filters and insert them after each other in the filter
 * chain.
 * 

 * This allows decoration of each filter and make it easier to reuse logic. Like the
 * {@link org.opentripplanner.routing.algorithm.filterchain.deletionflagger.MaxLimitFilter} is reused in
 * several places.
 */
public interface ItineraryListFilter {

    /**
     * Process the given itineraries returning the result.
     * 

     * This function should not change the List instance passed in, but may change the elements. It
     * must return a List with all the elements passed in (and possibly new elements). Note! that
     * the list passed into the filter might be immutable.
     * 

     * This can be achieved using streams. Example:
     * 
     * return itineraries.stream().peek(...).collect(Collectors.toList());
     * 
     */
    List filter(List itineraries);
}