AsDelegate.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.impl;
- import javax.annotation.Nonnull;
- import java.util.ArrayList;
- import java.util.Collection;
- import java.util.Collections;
- import java.util.List;
- import java.util.Optional;
- import java.util.function.Function;
- import it.tidalwave.util.As;
- import it.tidalwave.util.LazySupplier;
- import it.tidalwave.util.Parameters;
- import it.tidalwave.util.RoleFactory;
- import it.tidalwave.role.spi.OwnerRoleFactory;
- import it.tidalwave.role.spi.OwnerRoleFactoryProvider;
- import static it.tidalwave.util.Parameters.r;
- /***************************************************************************************************************************************************************
- *
- * An implementation of {@link As} that keeps some local roles and queries {@link OwnerRoleFactory}.
- *
- * @author Fabrizio Giudici
- *
- **************************************************************************************************************************************************************/
- public class AsDelegate implements As
- {
- @Nonnull
- private final Object owner;
- @Nonnull
- private final LazySupplier<OwnerRoleFactory> ownerRoleFactory;
- @Nonnull
- private final List<Object> roles = new ArrayList<>();
- /***********************************************************************************************************************************************************
- * Constructor for use in subclassing.
- **********************************************************************************************************************************************************/
- protected AsDelegate ()
- {
- owner = this;
- ownerRoleFactory = LazySupplier.of(() -> OwnerRoleFactoryProvider.getInstance().createRoleFactory(this));
- }
- /***********************************************************************************************************************************************************
- * Constructor for use in composition.
- *
- * @param owner the owner
- * @since 3.2-ALPHA-3 (refactored)
- **********************************************************************************************************************************************************/
- public AsDelegate (@Nonnull final Object owner)
- {
- this(owner, Collections.emptyList());
- }
- /***********************************************************************************************************************************************************
- * Constructor for use in composition. In addition to the mandatory owner, it accepts a single pre-instantiated
- * role, or a {@link RoleFactory} that will be invoked to create additional roles.
- *
- * @param owner the owner
- * @param role the role or {@link it.tidalwave.util.RoleFactory}
- * @since 3.2-ALPHA-3
- **********************************************************************************************************************************************************/
- public AsDelegate (@Nonnull final Object owner, @Nonnull final Object role)
- {
- this(owner, r(Parameters.mustNotBeArrayOrCollection(role, "role")));
- }
- /***********************************************************************************************************************************************************
- * Constructor for use in composition. In addition to the mandatory owner, it accepts a collection of
- * pre-instantiated roles, or instances of {@link RoleFactory} that will be invoked to create additional roles.
- *
- * @param owner the owner
- * @param roles roles or {@link it.tidalwave.util.RoleFactory} instances
- * @since 3.2-ALPHA-3 (refactored)
- **********************************************************************************************************************************************************/
- public AsDelegate (@Nonnull final Object owner, @Nonnull final Collection<Object> roles)
- {
- this(o -> OwnerRoleFactoryProvider.getInstance().createRoleFactory(o), owner, roles);
- }
- /***********************************************************************************************************************************************************
- * Constructor for use in tests. This constructor doesn't call {@link OwnerRoleFactoryProvider#getInstance()}.
- *
- * @param systemRoleFactoryFunction the factory
- * @param owner the owner
- * @param roles roles or {@link it.tidalwave.util.RoleFactory} instances
- * @since 3.2-ALPHA-3 (refactored)
- **********************************************************************************************************************************************************/
- public AsDelegate (@Nonnull final Function<Object, OwnerRoleFactory> systemRoleFactoryFunction,
- @Nonnull final Object owner,
- @Nonnull final Collection<Object> roles)
- {
- ownerRoleFactory = LazySupplier.of(() -> systemRoleFactoryFunction.apply(owner));
- this.owner = owner;
- this.roles.addAll(resolveFactories(roles));
- }
- /***********************************************************************************************************************************************************
- * {@inheritDoc}
- *
- * First, local roles are probed; then the owner, in case it directly implements the required role; at last,
- * the systemRoleFactory is invoked.
- **********************************************************************************************************************************************************/
- @Override @Nonnull
- public <T> Optional<T> maybeAs (@Nonnull final Class<? extends T> type)
- {
- for (final var role : roles)
- {
- if (type.isAssignableFrom(role.getClass()))
- {
- return Optional.of(type.cast(role));
- }
- }
- final var r = ownerRoleFactory.get().findRoles(type);
- return r.isEmpty() ? Optional.empty() : Optional.of(r.iterator().next());
- }
- /***********************************************************************************************************************************************************
- * {@inheritDoc}
- *
- * The list contains all the relevant local roles, as well as those retrieved by the delegate, in this order.
- **********************************************************************************************************************************************************/
- @Nonnull
- public <T> Collection<T> asMany (@Nonnull final Class<? extends T> type)
- {
- final var results = new ArrayList<T>();
- for (final var role : roles)
- {
- if (type.isAssignableFrom(role.getClass()))
- {
- results.add(type.cast(role));
- }
- }
- results.addAll(ownerRoleFactory.get().findRoles(type));
- return results;
- }
- /***********************************************************************************************************************************************************
- * Resolve the factories: if found, they are invoked and the produced roles are added to the list.
- *
- * @param roles the list of roles or factory roles
- * @return a list of roles
- **********************************************************************************************************************************************************/
- @Nonnull
- private List<Object> resolveFactories (@Nonnull final Collection<Object> roles)
- {
- final var result = new ArrayList<>();
- for (final var roleOrFactory : roles)
- {
- if (roleOrFactory instanceof RoleFactory)
- {
- result.add(((RoleFactory<Object>)roleOrFactory).createRoleFor(owner));
- }
- else
- {
- result.add(roleOrFactory);
- }
- }
- return result;
- }
- }