org.springframework.test.context.support.AnnotationConfigContextLoaderUtils.java Source code

Introduction

Here is the source code for org.springframework.test.context.support.AnnotationConfigContextLoaderUtils.java

Source

/*
 * Copyright 2002-2017 the original author or authors.
 *
 * 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.
 */

package org.springframework.test.context.support;

import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.context.annotation.Configuration;
import org.springframework.core.annotation.AnnotatedElementUtils;
import org.springframework.lang.Nullable;
import org.springframework.test.context.SmartContextLoader;
import org.springframework.util.Assert;

/**
 * Utility methods for {@link SmartContextLoader SmartContextLoaders} that deal
 * with annotated classes (e.g., {@link Configuration @Configuration} classes).
 *
 * @author Sam Brannen
 * @since 3.2
 */
public abstract class AnnotationConfigContextLoaderUtils {

    private static final Log logger = LogFactory.getLog(AnnotationConfigContextLoaderUtils.class);

    /**
     * Detect the default configuration classes for the supplied test class.
     * <p>The returned class array will contain all static nested classes of
     * the supplied class that meet the requirements for {@code @Configuration}
     * class implementations as specified in the documentation for
     * {@link Configuration @Configuration}.
     * <p>The implementation of this method adheres to the contract defined in the
     * {@link org.springframework.test.context.SmartContextLoader SmartContextLoader}
     * SPI. Specifically, this method uses introspection to detect default
     * configuration classes that comply with the constraints required of
     * {@code @Configuration} class implementations. If a potential candidate
     * configuration class does not meet these requirements, this method will log a
     * debug message, and the potential candidate class will be ignored.
     * @param declaringClass the test class that declared {@code @ContextConfiguration}
     * @return an array of default configuration classes, potentially empty but
     * never {@code null}
     */
    public static Class<?>[] detectDefaultConfigurationClasses(Class<?> declaringClass) {
        Assert.notNull(declaringClass, "Declaring class must not be null");

        List<Class<?>> configClasses = new ArrayList<>();

        for (Class<?> candidate : declaringClass.getDeclaredClasses()) {
            if (isDefaultConfigurationClassCandidate(candidate)) {
                configClasses.add(candidate);
            } else {
                if (logger.isDebugEnabled()) {
                    logger.debug(String.format(
                            "Ignoring class [%s]; it must be static, non-private, non-final, and annotated "
                                    + "with @Configuration to be considered a default configuration class.",
                            candidate.getName()));
                }
            }
        }

        if (configClasses.isEmpty()) {
            if (logger.isInfoEnabled()) {
                logger.info(String.format(
                        "Could not detect default configuration classes for test class [%s]: "
                                + "%s does not declare any static, non-private, non-final, nested classes "
                                + "annotated with @Configuration.",
                        declaringClass.getName(), declaringClass.getSimpleName()));
            }
        }

        return configClasses.toArray(new Class<?>[configClasses.size()]);
    }

    /**
     * Determine if the supplied {@link Class} meets the criteria for being
     * considered a <em>default configuration class</em> candidate.
     * <p>Specifically, such candidates:
     * <ul>
     * <li>must not be {@code null}</li>
     * <li>must not be {@code private}</li>
     * <li>must not be {@code final}</li>
     * <li>must be {@code static}</li>
     * <li>must be annotated or meta-annotated with {@code @Configuration}</li>
     * </ul>
     * @param clazz the class to check
     * @return {@code true} if the supplied class meets the candidate criteria
     */
    private static boolean isDefaultConfigurationClassCandidate(@Nullable Class<?> clazz) {
        return (clazz != null && isStaticNonPrivateAndNonFinal(clazz)
                && AnnotatedElementUtils.hasAnnotation(clazz, Configuration.class));
    }

    private static boolean isStaticNonPrivateAndNonFinal(Class<?> clazz) {
        Assert.notNull(clazz, "Class must not be null");
        int modifiers = clazz.getModifiers();
        return (Modifier.isStatic(modifiers) && !Modifier.isPrivate(modifiers) && !Modifier.isFinal(modifiers));
    }

}