001/*
002 * Copyright 2022-2025 Revetware LLC.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package com.soklet;
018
019import javax.annotation.Nonnull;
020
021/**
022 * Contract for concrete instance generation given type information.
023 * <p>
024 * A standard implementation can be acquired via the {@link #withDefaults()} factory method.
025 * <p>
026 * See <a href="https://www.soklet.com/docs/instance-creation">https://www.soklet.com/docs/instance-creation</a> for detailed documentation.
027 *
028 * @author <a href="https://www.revetkn.com">Mark Allen</a>
029 */
030@FunctionalInterface
031public interface InstanceProvider {
032        /**
033         * Vends an instance of the given class.
034         * <p>
035         * The instance does not necessarily have to be new for every invocation (for example, implementors might return cached instances).
036         *
037         * @param instanceClass type token which represents the class to instantiate
038         * @param <T>           the type of class to instantiate
039         * @return an instance of {@code T}
040         */
041        @Nonnull
042        <T> T provide(@Nonnull Class<T> instanceClass);
043
044        /**
045         * Acquires an {@link InstanceProvider} with a default "{@code newInstance()}" instantiation strategy.
046         * <p>
047         * Callers should not rely on reference identity; this method may return a new or cached instance.
048         *
049         * @return an {@code InstanceProvider} with default settings
050         */
051        @Nonnull
052        static InstanceProvider withDefaults() {
053                return DefaultInstanceProvider.defaultInstance();
054        }
055}