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.applib.services.tablecol;
  
  import java.util.List;
  
  import org.jspecify.annotations.Nullable;
  
  /**
   * Provides the ability to reorder columns in both parented- and
   * standalone tables.
   *
   * <p>
   *     If a property is excluded from the returned list, then no column will
   *     be rendered, so the API can also be used to suppress columns completely.
   * </p>
   *
   * <p>
   *     There can be multiple implementations of this service registered,
   *     ordered as per the Spring
   *     {@link org.springframework.core.annotation.Order} annotation (or equivalent).
   *     The result of the first service implementation to return a
   *     non-<code>null</code> value will be used.
   * </p>
   *
   * <p>
   *      If all provided implementations return <code>null</code>, then the
   *      framework will fallback to a default implementation.
   * </p>
   *
   * <p>
   *     The similar {@link TableColumnVisibilityService} SPI is the preferred way to
   *     suppress columns.  As noted above, this {@link TableColumnOrderService}
   *     can also be used to suppress columns.  The reason that the
   *     {@link TableColumnVisibilityService} is needed in addition to this SPI is
   *     because of the way that non-null values are handled; as soon as one
   *     implementation has an opinion on the order of columns, no other
   *     services are consulted.  Trying to combine both responsibilities
   *     (reordering and filtering only in a single
   *     {@link TableColumnOrderService} would result in the user needing to take
   *     a lot of care in the relative priority of different implementations.
   *     Separating out the filter responsibility in the
   *     {@link TableColumnVisibilityService} SPIs eliminates these difficulties).
   * </p>
   *
   * @since 1.x {@index}
   */
  public interface TableColumnOrderService {
  
      /**
       * For the parent collection owned by the specified parent and collection Id, return a list of association ids
       * to be rendered as columns, in a particular order; those not included will be hidden.
       *
       * @param parent - the parent object (eg an <i>Order</i>).
       * @param collectionId - the logical member name that identifies the collection within its domain object type (eg <i>items</i>).
       * @param elementType - the class of the elements of the collection (eg <i>OrderItem</i>s in a collection of <i>Order#items</i>).
       * @param associationIds - the associations (properties or collections) of the element type that should be rendered in the parent object's collection
       *
       * @return <code>null</code> if has no opinion/provides no reordering for this parent and collection.
       */
      @Nullable
      List<String> orderParented(
              final Object parent,
              final String collectionId,
              final Class<?> elementType,
              final List<String> associationIds);
  
      /**
       * For the standalone collection of the specified type,  return a list of association ids to be rendered as columns,
       * in a particular order; those not included will be hidden.
       *
       * @param domainType - the class of the domain object being rendered in the standalone collection
       * @param associationIds - the associations (properties or collections) of the domain type that should be rendered in the parent object's collection
       *
       * @return <code>null</code> if has no opinion/provides no reordering for this type.
       */
      @Nullable
      List<String> orderStandalone(
              final Class<?> domainType,
              final List<String> associationIds);
  
  }
  