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.grid;
  
  import org.apache.causeway.applib.annotation.ActionLayout;
  import org.apache.causeway.applib.annotation.CollectionLayout;
  import org.apache.causeway.applib.annotation.DomainObjectLayout;
  import org.apache.causeway.applib.annotation.PropertyLayout;
  import org.apache.causeway.applib.layout.grid.Grid;
  import org.apache.causeway.applib.services.layout.LayoutExportStyle;
  import org.apache.causeway.commons.internal.exceptions._Exceptions;
  
  /**
   * Provides the ability to load the XML layout (grid) for a domain class.
   *
   * @since 1.x {@index}
   */
  public interface GridService {
  
      /**
       * Whether dynamic reloading of layouts is enabled.
       *
       * <p>
       *     The default implementation just delegates to the configured
       *     {@link GridLoaderService}; the default implementation of <i>that</i>
       *     service enables reloading wihle prototyping, disables in production.
       * </p>
       */
      boolean supportsReloading();
  
      /**
       * To support metamodel invalidation/rebuilding of spec.
       *
       * <p>
       *     The default implementation just delegates to the configured
       *     {@link GridLoaderService}.
       * </p>
       */
      void remove(Class<?> domainClass);
  
      /**
       * Whether any persisted layout metadata (eg a <code>.layout.xml</code> file) exists for this domain class.
       *
       * <p>
       *     The default implementation just delegates to the configured
       *     {@link GridLoaderService}.
       * </p>
       */
      boolean existsFor(Class<?> domainClass);
  
      /**
       * Returns a new instance of a {@link Grid} for the specified domain class,
       * for example as loaded from a <code>layout.xml</code> file.
       *
       * <p>
       *     If non exists, returns <code>null</code>.  (The caller can then
       *     use {@link GridService#defaultGridFor(Class)} to obtain a
       *     default grid if necessary).
       * </p>
       *
       * <p>
       *     The default implementation just delegates to the configured
       *     {@link GridLoaderService}.
       * </p>
       */
      Grid load(final Class<?> domainClass);
  
      /**
       * Returns an alternative layout for the domain class.
       *
       * <p>
       *     The alternative layout name can for example be returned by the
       *     domain object's <code>layout()</code> method, whereby - based on the
       *     state of the domain object - it requests a different layout be used.
       * </p>
       *
       * <p>
       *     The default implementation just delegates to the configured
       *     {@link GridLoaderService}; the default implementation of <i>that</i>
       *     service uses the layout name to search for a differently
       *      named layout file, <code>[domainClass].layout.[layout].xml</code>.
       * </p>
       */
      Grid load(Class<?> domainClass, String layout);
  
      /**
       * Returns a default grid; eg where none can be loaded using {@link #load(Class)}.
       *
       * <p>
       * Used when no existing grid layout exists for a domain class.
       * </p>
       *
       * <p>
       *     The default implementation searches through all available
       *     {@link GridSystemService}s and asks each in turn for a
       *     {@link GridSystemService#defaultGrid(Class) default grid}.
       * </p>
       */
      Grid defaultGridFor(Class<?> domainClass);
  
      /**
       * Returns a normalized grid for the domain class obtained previously using {@link #load(Class)}.
       *
       * <p>
       *     If a 'normalized' grid is persisted as the <code>layout.xml</code>, then the expectation is that
       *     any ordering metadata from layout annotations can be removed from the domain class
       *     because the binding of properties/collections/actions will be within the XML.  However, the layout
       *     annotations ({@link DomainObjectLayout}, {@link ActionLayout}, {@link PropertyLayout} and
       *     {@link CollectionLayout}) (if present) will continue to be used to provide additional layout metadata.  Of
       *     course, there is nothing to prevent the developer from extending the layout XML to also include the
       *     layout XML (in other words moving towards a {@link #complete(Grid) complete} grid.  Metadata within the
       *     <code>layout.xml</code> file takes precedence over any annotations.
       * </p>
       */
      Grid normalize(final Grid grid);
  
      /**
       * Modifies the provided {@link Grid} with additional metadata, broadly speaking corresponding to the
       * {@link DomainObjectLayout}, {@link ActionLayout}, {@link PropertyLayout} and {@link CollectionLayout}.
       *
       * <p>
       *     If a 'complete' grid is persisted as the <code>layout.xml</code>, then there should be no need
       *     for any of the layout annotations,
       *     to be required in the domain class itself.
       * </p>
       */
      Grid complete(Grid grid);
  
      /**
       * Modifies the provided {@link Grid}, removing all metadata except the basic grid structure.
       *
       * <p>
       *     If a 'minimal' grid is persisted as the <code>layout.xml</code>, then the expectation is that
       *     most of the layout annotations ({@link DomainObjectLayout}, {@link ActionLayout}, {@link PropertyLayout},
       *     {@link CollectionLayout} will still be retained in the domain class code.
       * </p>
       *
       * @param grid
       */
      Grid minimal(Grid grid);
  
      // -- LAYOUT EXPORT
  
      GridMarshallerService<? extends Grid> marshaller();
  
      default Grid toGridForExport(
              final Class<?> domainClass,
              final LayoutExportStyle style) {
  
          // don't use the grid from the facet, because it will be modified subsequently.
          Grid grid = load(domainClass);
          if(grid == null) {
              grid = defaultGridFor(domainClass);
          }
          grid = normalize(grid); // required so the grid's tns and schema-locations get populated
          if (style == LayoutExportStyle.COMPLETE) {
              return complete(grid);
          }
          if (style == LayoutExportStyle.MINIMAL) {
              return minimal(grid);
          }
          throw _Exceptions.unmatchedCase(style);
      }
  
  }
  