MappingFinder.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.util.impl.finder;

  28. import javax.annotation.Nonnull;
  29. import javax.annotation.concurrent.Immutable;
  30. import java.util.List;
  31. import java.util.function.Function;
  32. import it.tidalwave.util.Finder;
  33. import it.tidalwave.util.spi.SimpleFinderSupport;
  34. import static java.util.stream.Collectors.*;

  35. /***********************************************************************************************************************
  36.  *
  37.  * A {@link Finder} which retrieve results from another instance applying a {@link Function}.
  38.  *
  39.  * @author  Fabrizio Giudici
  40.  *
  41.  **********************************************************************************************************************/
  42. @Immutable
  43. public final class MappingFinder<T, U> extends SimpleFinderSupport<T>
  44.   {
  45.     private static final long serialVersionUID = -6359683808082070089L;

  46.     @Nonnull
  47.     private final transient Finder<? extends U> delegate;

  48.     @Nonnull
  49.     private final transient Function<? super U, ? extends T> decorator;

  50.     public MappingFinder (@Nonnull final Finder<? extends U> delegate,
  51.                           @Nonnull final Function<? super U, ? extends T> decorator)
  52.       {
  53.         this.delegate = delegate;
  54.         this.decorator = decorator;
  55.       }

  56.     public MappingFinder (@Nonnull final MappingFinder other, @Nonnull final Object override)
  57.       {
  58.         super(other, override);
  59.         final MappingFinder<T, U> source = getSource(MappingFinder.class, other, override);
  60.         this.delegate = source.delegate;
  61.         this.decorator = source.decorator;
  62.       }

  63.     @Override @Nonnull
  64.     protected List<T> computeResults()
  65.       {
  66.         return delegate.results().stream().map(decorator).collect(toList());
  67.       }
  68.   }