/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.server.web;

/**
 * Used to allow custom values to be injected into JAX-RS classes.
 *
 * @param <T> the type of the value, or an interface the value implements.
 */
public interface Injectable<T> {
    /**
     * Get the injectable value.
     *
     * @return the injectable value
     */
    T getValue();

    /**
     * The type that resources should ask for to get this value;
     * this can either be the concrete class, or some interface the
     * value instance implements.
     *
     * @return a class that methods that want this value injected should ask for
     */
    Class<T> getType();

    /**
     * Utility to wrap a singleton value as an injectable.
     *
     * @param type the type that JAX-RS classes should ask for
     * @param obj the value
     * @param <T> same as type
     * @return
     */
    static <T> Injectable<T> injectable(Class<T> type, T obj) {
        return new Injectable<>() {
            @Override
            public T getValue() {
                return obj;
            }

            @Override
            public Class<T> getType() {
                return type;
            }
        };
    }
}
