001/*
002 * Copyright 2023 the original author or authors.
003 * <p>
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 * <p>
008 * https://www.apache.org/licenses/LICENSE-2.0
009 * <p>
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 */
016package de.cuioss.test.valueobjects.generator.dynamic.impl;
017
018import java.lang.reflect.InvocationHandler;
019import java.util.Optional;
020
021import de.cuioss.test.generator.TypedGenerator;
022import de.cuioss.tools.reflect.MoreReflection;
023import lombok.AccessLevel;
024import lombok.RequiredArgsConstructor;
025
026/**
027 * Creates proxies for given interfaces, should only be used as last line of
028 * defense.
029 *
030 * @author Oliver Wolff
031 * @param <T> the type of objects to be generated
032 */
033@RequiredArgsConstructor(access = AccessLevel.PRIVATE)
034public class InterfaceProxyGenerator<T> implements TypedGenerator<T> {
035
036    private static final InvocationHandler DEFAULT_HANDLER = new DefaultInvocationHandler();
037
038    private final Class<T> type;
039
040    @Override
041    public T next() {
042        return MoreReflection.newProxy(type, DEFAULT_HANDLER);
043    }
044
045    @Override
046    public Class<T> getType() {
047        return type;
048    }
049
050    /**
051     * Factory method for creating an instance of {@link InterfaceProxyGenerator}.
052     * It only works with interfaces.
053     *
054     * @param type to be checked, should be an interface
055     * @return an {@link Optional} on the corresponding {@link TypedGenerator} if
056     *         the given type is an interfaces, otherwise {@link Optional#empty()}
057     */
058    public static final <T> Optional<TypedGenerator<T>> getGeneratorForType(final Class<T> type) {
059        if (null == type || type.isAnnotation() || !type.isInterface()) {
060            return Optional.empty();
061        }
062        return Optional.of(new InterfaceProxyGenerator<>(type));
063    }
064}