content: /*
   *  Licensed to the Apache Software Foundation (ASF) under one
   *  or more contributor license agreements.  See the NOTICE file
   *  distributed with this work for additional information
   *  regarding copyright ownership.  The ASF licenses this file
   *  to you under the Apache 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://www.apache.org/licenses/LICENSE-2.0
   *
   *  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.apache.causeway.viewer.wicket.ui.components.collection.selector;
  
  import org.apache.wicket.Component;
  
  public interface CollectionPresentationSelectorProvider {
      CollectionPresentationSelectorPanel getSelectorDropdownPanel();
  
      /**
       * Searches up the component hierarchy looking for a parent that implements
       * {@link org.apache.causeway.viewer.wicket.ui.components.collection.selector.CollectionPresentationSelectorProvider}.
       *
       * @return the panel, or null (if there are no alternative views)
       */
      public static CollectionPresentationSelectorPanel getCollectionSelectorProvider(Component component) {
          while(component != null) {
              if(component instanceof CollectionPresentationSelectorProvider) {
                  return ((CollectionPresentationSelectorProvider) component).getSelectorDropdownPanel();
              }
              component = component.getParent();
          }
          throw new IllegalStateException("Could not locate parent that implements CollectionSelectorProvider");
      }
  
  }
  