PresentationModelCollectors.java

  1. /*
  2.  * *********************************************************************************************************************
  3.  *
  4.  * TheseFoolishThings: Miscellaneous utilities
  5.  * http://tidalwave.it/projects/thesefoolishthings
  6.  *
  7.  * Copyright (C) 2009 - 2023 by Tidalwave s.a.s. (http://tidalwave.it)
  8.  *
  9.  * *********************************************************************************************************************
  10.  *
  11.  * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
  12.  * the License. You may obtain a copy of the License at
  13.  *
  14.  *     http://www.apache.org/licenses/LICENSE-2.0
  15.  *
  16.  * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
  17.  * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the License for the
  18.  * specific language governing permissions and limitations under the License.
  19.  *
  20.  * *********************************************************************************************************************
  21.  *
  22.  * git clone https://bitbucket.org/tidalwave/thesefoolishthings-src
  23.  * git clone https://github.com/tidalwave-it/thesefoolishthings-src
  24.  *
  25.  * *********************************************************************************************************************
  26.  */
  27. package it.tidalwave.role.ui.spi;

  28. import javax.annotation.Nonnull;
  29. import java.util.ArrayList;
  30. import java.util.Collection;
  31. import java.util.Collections;
  32. import java.util.List;
  33. import java.util.function.Function;
  34. import java.util.stream.Stream;
  35. import java.util.stream.StreamSupport;
  36. import it.tidalwave.util.As;
  37. import it.tidalwave.util.spi.ArrayListCollectorSupport;
  38. import it.tidalwave.role.Composite;
  39. import it.tidalwave.role.SimpleComposite;
  40. import it.tidalwave.role.ui.PresentationModel;
  41. import static it.tidalwave.util.Parameters.r;
  42. import static it.tidalwave.role.ui.Presentable._Presentable_;

  43. /***********************************************************************************************************************
  44.  *
  45.  * A {@link java.util.stream.Collector} which collects a {@link Stream} of {@link PresentationModel}s into a single
  46.  * {@code PresentationModel} with a {@code Composite<PresentationModel>} role containing them.
  47.  *
  48.  * @author  Fabrizio Giudici
  49.  *
  50.  **********************************************************************************************************************/
  51. public class PresentationModelCollectors extends ArrayListCollectorSupport<PresentationModel, PresentationModel>
  52.   {
  53.     @Nonnull
  54.     private final Collection<Object> roles = new ArrayList<>();
  55.    
  56.     /*******************************************************************************************************************
  57.      *
  58.      * A {@link java.util.stream.Collector} which collects a {@link Stream} of {@link PresentationModel}s into a single
  59.      * {@code PresentationModel} with a {@link Composite} role containing them. In other words:
  60.      *
  61.      * <pre>
  62.      * List&lt;PresentationModel&gt; pms = ...
  63.      * PresentationModel compositePm = pms.stream().collect(toCompositePresentationModel());
  64.      * // same contents as childrenPms
  65.      * List&lt;PresentationModel&gt; childrenPms = compositePm.as(_Composite_).findChildren().results();
  66.      * </pre>
  67.      *
  68.      * @param   roles   some extra roles included in the resulting {@code PresentationModel}
  69.      * @return          a {@code PresentationModel}
  70.      * @since   3.2-ALPHA-3 (refactored)
  71.      *
  72.      ******************************************************************************************************************/
  73.     @Nonnull
  74.     public static PresentationModelCollectors toCompositePresentationModel (@Nonnull final Collection<Object> roles)
  75.       {
  76.         return new PresentationModelCollectors(roles);
  77.       }

  78.     @Nonnull
  79.     public static PresentationModelCollectors toCompositePresentationModel()
  80.       {
  81.         return toCompositePresentationModel((Collection<Object>)Collections.emptyList());
  82.       }

  83.     /*******************************************************************************************************************
  84.      *
  85.      * A facility method that creates a composite {@link PresentationModel} out of an iterable (which means an array,
  86.      * a collection or a stream) of objects implementing {@link As}. For each  object in the iterable, its {@code
  87.      * PresentationModel} is created by means of invoking its {@link it.tidalwave.role.ui.Presentable} role. Then all
  88.      * the {@code PresentationModel}s are aggregated into the composite.
  89.      *
  90.      * A function which creates specific roles for each {@code PresentationModel} can be specified. The function can
  91.      * return a single role or multiple roles in form of an array {@code Object[]}.
  92.      *
  93.      * @param   <T>             the type of the objects
  94.      * @param   i               the {@code Iterable}
  95.      * @param   roleCreator     the function to create roles
  96.      * @return                  the composite {@code PresentationModel}
  97.      *
  98.      ******************************************************************************************************************/
  99.     @Nonnull
  100.     public static <T extends As> PresentationModel toCompositePresentationModel (
  101.             @Nonnull final Iterable<T> i,
  102.             @Nonnull final Function<T, Object> roleCreator)
  103.       {
  104.         return StreamSupport.stream(i.spliterator(), false)
  105.                             .map(o -> o.as(_Presentable_).createPresentationModel(r(roleCreator.apply(o))))
  106.                             .collect(PresentationModelCollectors.toCompositePresentationModel());
  107.       }

  108.     /*******************************************************************************************************************
  109.      *
  110.      * A facility simplified version of
  111.      * {@link #toCompositePresentationModel(java.lang.Iterable, java.util.function.Function)}.
  112.      *
  113.      * @param   <T>             the type of the objects
  114.      * @param   i               the {@code Iterable}
  115.      * @return                  the composite {@code PresentationModel}
  116.      *
  117.      ******************************************************************************************************************/
  118.     @Nonnull
  119.     public static <T extends As> PresentationModel toCompositePresentationModel (@Nonnull final Iterable<T> i)
  120.       {
  121.         return toCompositePresentationModel(i, o -> new Object[0]);
  122.       }

  123.     /*******************************************************************************************************************
  124.      *
  125.      * {@inheritDoc}
  126.      *
  127.      ******************************************************************************************************************/
  128.     @Override @Nonnull
  129.     public Function<List<PresentationModel>, PresentationModel> finisher()
  130.       {
  131.         return childrenPms -> PresentationModel.of("", r(roles, SimpleComposite.ofCloned(childrenPms)));
  132.       }
  133.    
  134.     /*******************************************************************************************************************
  135.      *
  136.      *
  137.      ******************************************************************************************************************/
  138.     private PresentationModelCollectors (@Nonnull final Collection<Object> roles)
  139.       {
  140.         this.roles.addAll(roles);
  141.       }
  142.   }