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
   *
   *      https://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.tools.ant.types.resources;
  
  import java.util.Collection;
  import java.util.LinkedHashSet;
  import java.util.Set;
  import java.util.function.Function;
  import java.util.stream.Collectors;
  import java.util.stream.Stream;
  
  import org.apache.tools.ant.Project;
  import org.apache.tools.ant.types.Resource;
  import org.apache.tools.ant.types.ResourceCollection;
  
  /**
   * ResourceCollection representing the union of multiple nested ResourceCollections.
   * @since Ant 1.7
   */
  public class Union extends BaseResourceCollectionContainer {
  
      /**
       * Static convenience method to union an arbitrary set of Resources.
       * @param rc a ResourceCollection.
       * @return a Union.
       */
      public static Union getInstance(ResourceCollection rc) {
          return rc instanceof Union ? (Union) rc : new Union(rc);
      }
  
      /**
       * Default constructor.
       */
      public Union() {
      }
  
      /**
       * Create a new Union.
       * @param project owning Project
       */
      public Union(Project project) {
          super(project);
      }
  
      /**
       * Convenience constructor.
       * @param rc the ResourceCollection to add.
       */
      public Union(ResourceCollection rc) {
          this(Project.getProject(rc), rc);
      }
  
      /**
       * Convenience constructor.
       * @param project owning Project
       * @param rc the ResourceCollection to add.
       */
      public Union(Project project, ResourceCollection rc) {
          super(project);
          add(rc);
      }
  
      /**
       * Returns all Resources in String format. Provided for
       * convenience in implementing Path.
       * @return String array of Resources.
       */
      public String[] list() {
          if (isReference()) {
              return getRef().list();
          }
          return streamResources().map(Object::toString).toArray(String[]::new);
      }
  
      /**
       * Convenience method.
       * @return Resource[]
       */
      public Resource[] listResources() {
          if (isReference()) {
              return getRef().listResources();
          }
          return streamResources().toArray(Resource[]::new);
      }
  
      /**
       * Unify the contained Resources.
       * @return a Collection of Resources.
       */
      @Override
      protected Collection<Resource> getCollection() {
          return getAllResources();
      }
  
      /**
       * Unify the contained Resources.
       * @param <T> resource type
       * @param asString indicates whether the resulting Collection
       *        should contain Strings instead of Resources.
       * @return a Collection of Resources.
       */
      @Deprecated
      @SuppressWarnings("unchecked")
      protected <T> Collection<T> getCollection(boolean asString) { // TODO untypable
          return asString ? (Collection<T>) getAllToStrings()
              : (Collection<T>) getAllResources();
      }
  
      /**
       * Get a collection of strings representing the unified resource set (strings may duplicate).
       * @return Collection&lt;String&gt;
       */
      protected Collection<String> getAllToStrings() {
          return streamResources(Object::toString)
              .collect(Collectors.toCollection(LinkedHashSet::new));
      }
  
      /**
       * Get the unified set of contained Resources.
       * @return Set&lt;Resource&gt;
       */
      protected Set<Resource> getAllResources() {
          return streamResources()
              .collect(Collectors.toCollection(LinkedHashSet::new));
      }
  
      private Union getRef() {
          return getCheckedRef(Union.class);
      }
  
      private Stream<? extends Resource> streamResources() {
          return streamResources(Function.identity());
      }
  
      private <T> Stream<? extends T> streamResources(
          Function<? super Resource, ? extends T> mapper) {
          return getResourceCollections().stream()
              .flatMap(ResourceCollection::stream).map(mapper).distinct();
      }
  }
  