FlavorPrioritySelector.java

/**
 * Licensed to The Apereo Foundation under one or more contributor license
 * agreements. See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 *
 *
 * The Apereo Foundation licenses this file to you under the Educational
 * Community License, Version 2.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of the License
 * at:
 *
 *   http://opensource.org/licenses/ecl2.txt
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations under
 * the License.
 *
 */

package org.opencastproject.mediapackage.selector;

import org.opencastproject.mediapackage.MediaPackage;
import org.opencastproject.mediapackage.MediaPackageElement;
import org.opencastproject.mediapackage.MediaPackageElementFlavor;

import java.util.Collection;
import java.util.HashSet;
import java.util.Set;

/**
 * This selector will return one or zero <code>MediaPackageElements</code> from a <code>MediaPackage</code>, following
 * these rules:
 * <ul>
 * <li>Elements will be returned depending on tags that have been set</li>
 * <li>If no tags have been specified, all the elements will be taken into account</li>
 * <li>The result is one or zero elements</li>
 * <li>The element is selected based on the order of flavors</li>
 * </ul>
 */
public class FlavorPrioritySelector<T extends MediaPackageElement> extends AbstractMediaPackageElementSelector<T> {

  /**
   * {@inheritDoc}
   *
   * @see org.opencastproject.mediapackage.MediaPackageElementSelector#select(org.opencastproject.mediapackage.MediaPackage,
   *      boolean)
   */
  public Collection<T> select(MediaPackage mediaPackage, boolean withTagsAndFlavors) {
    Set<T> candidates = new HashSet<T>();
    Set<T> result = new HashSet<T>();

    // Have the super implementation match type, flavor and tags
    candidates.addAll(super.select(mediaPackage, withTagsAndFlavors));

    if (flavors.isEmpty())
      return candidates;

    // Return the first element based on the flavor
    buildResult: for (MediaPackageElementFlavor flavor : flavors) {
      for (T element : candidates) {
        if (flavor.equals(element.getFlavor())) {
          result.add(element);
          break buildResult;
        }
      }
    }

    return result;
  }

}