Composite.java
- /*
- * *************************************************************************************************************************************************************
- *
- * TheseFoolishThings: Miscellaneous utilities
- * http://tidalwave.it/projects/thesefoolishthings
- *
- * Copyright (C) 2009 - 2024 by Tidalwave s.a.s. (http://tidalwave.it)
- *
- * *************************************************************************************************************************************************************
- *
- * Licensed 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.
- *
- * *************************************************************************************************************************************************************
- *
- * git clone https://bitbucket.org/tidalwave/thesefoolishthings-src
- * git clone https://github.com/tidalwave-it/thesefoolishthings-src
- *
- * *************************************************************************************************************************************************************
- */
- package it.tidalwave.role;
- import javax.annotation.Nonnull;
- import java.util.Optional;
- import java.util.function.Consumer;
- import java.util.stream.Stream;
- import it.tidalwave.util.Finder;
- /***************************************************************************************************************************************************************
- *
- * The role of a composite object, that is an object which contains children. They are exposed by means of a
- * {@link Finder}.
- *
- * @stereotype Role
- *
- * @author Fabrizio Giudici
- * @it.tidalwave.javadoc.stable
- *
- **************************************************************************************************************************************************************/
- @FunctionalInterface
- public interface Composite<T, F extends Finder<? extends T>>
- {
- public static final Class<Composite> _Composite_ = Composite.class;
- /***********************************************************************************************************************************************************
- * A default <code>Composite</code> with no children.
- **********************************************************************************************************************************************************/
- public static final Composite<Object, Finder<Object>> DEFAULT = new Composite<>()
- {
- @Override @Nonnull
- public Finder<Object> findChildren()
- {
- return Finder.empty();
- }
- };
- /***********************************************************************************************************************************************************
- * {@return the children of this object}.
- **********************************************************************************************************************************************************/
- @Nonnull
- public F findChildren();
- /***********************************************************************************************************************************************************
- * {@return a stream of children}.
- * @since 3.2-ALPHA-23
- **********************************************************************************************************************************************************/
- @Nonnull
- public default Stream<? extends T> stream()
- {
- return findChildren().stream();
- }
- /***********************************************************************************************************************************************************
- * Iterates through children.
- * @param consumer the consumer
- * @since 3.2-ALPHA-23
- **********************************************************************************************************************************************************/
- public default void forEach (@Nonnull final Consumer<? super T> consumer)
- {
- stream().forEach(consumer);
- }
- /***********************************************************************************************************************************************************
- * A visitor that can travel through the {@code Composite} items.
- * @param <T> the type of the composite
- * @param <R> the type of the result
- **********************************************************************************************************************************************************/
- @SuppressWarnings("EmptyMethod")
- public static interface Visitor<T, R>
- {
- /*******************************************************************************************************************************************************
- * Visits an object. This method is called before visiting children (pre-order).
- * @param object the visited object
- ******************************************************************************************************************************************************/
- public default void preVisit (@Nonnull final T object)
- {
- }
- /*******************************************************************************************************************************************************
- * Visits an object. This method is actually called just after {@link #preVisit(Object)}, it makes sense to implement it when you don't need to
- * distinguish between pre-order and post-order traversal.
- * @param object the visited object
- ******************************************************************************************************************************************************/
- public default void visit (@Nonnull final T object)
- {
- }
- /*******************************************************************************************************************************************************
- * Visits an object. This method is called after visiting children (post-order).
- * @param object the visited object
- ******************************************************************************************************************************************************/
- public default void postVisit (@Nonnull final T object)
- {
- }
- /*******************************************************************************************************************************************************
- * {@return the value of this visitor}.
- ******************************************************************************************************************************************************/
- @Nonnull
- public default Optional<R> getValue()
- {
- return Optional.empty();
- }
- }
- }