Arakne / Araknemu

 * This file is part of Araknemu.

 *

 * Araknemu is free software: you can redistribute it and/or modify

 * it under the terms of the GNU Lesser General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * Araknemu is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with Araknemu.  If not, see <https://www.gnu.org/licenses/>.

 *

 * Copyright (c) 2017-2021 Vincent Quatrevieux

 */

package fr.quatrevieux.araknemu.core.di;

import java.util.HashMap;

import java.util.Map;

/**

 * Container with manually defined services as scope

 *

 * Usage:

 * <pre>{@code

 * Container container = ...;

 * Container scoped = container.with(myService, MyServiceInterface.class);

 *

 * scoped.get(MyServiceInterface.class); // Will return myService

 * }</pre>

 */

public final class ScopedContainer implements Container {

    private final Container container;

    private final Map<Class, Object> scope;

    private ScopedContainer(Container container, Map<Class, Object> scope) {

        this.container = container;

        this.scope = scope;

    }

    @Override

    public boolean has(Class type) {

        return scope.containsKey(type) || container.has(type);

    }

    @Override

    public void register(ContainerModule module) {

        throw new UnsupportedOperationException("Cannot register a module on a scoped container");

    }

    /**

     * Create the scoped container from the given mapping

     *

     * @param container Base container

     * @param mappings The mapping

     *

     * @return The created container instance

     */

    public static ScopedContainer fromMapping(Container container, Mapping[] mappings) {

        final Map<Class, Object> scope = new HashMap<>();

        for (Mapping mapping : mappings) {

            scope.put(mapping.value.getClass(), mapping.value);

            for (Class type : mapping.interfaces) {

                scope.put(type, mapping.value);

            }

        }

        return new ScopedContainer(container, scope);

    }

    /**

     * An interfaces / value mapping

     *

     * @param <T> The base type

     */

    public static final class Mapping<T> {

        private final T value;

        private final Class[] interfaces;

        public Mapping(T value, Class<? super T>... interfaces) {

            this.value = value;

            this.interfaces = interfaces;

        }

    }

}