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

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

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/*
 * 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.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

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

import org.springframework.context.ApplicationContextInitializer;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.ContextConfigurationAttributes;
import org.springframework.util.Assert;

/**
 * Utility methods for working with {@link ApplicationContextInitializer
 * ApplicationContextInitializers}.
 *
 * <p>Although {@code ApplicationContextInitializerUtils} was first introduced
 * in Spring Framework 4.1, the initial implementations of methods in this class
 * were based on the existing code base in {@code ContextLoaderUtils}.
 *
 * @author Sam Brannen
 * @since 4.1
 * @see ContextConfiguration#initializers
 */
abstract class ApplicationContextInitializerUtils {

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

    private ApplicationContextInitializerUtils() {
        /* no-op */
    }

    /**
     * Resolve the set of merged {@code ApplicationContextInitializer} classes for the
     * supplied list of {@code ContextConfigurationAttributes}.
     *
     * <p>Note that the {@link ContextConfiguration#inheritInitializers inheritInitializers}
     * flag of {@link ContextConfiguration @ContextConfiguration} will be taken into
     * consideration. Specifically, if the {@code inheritInitializers} flag is set to
     * {@code true} for a given level in the class hierarchy represented by the provided
     * configuration attributes, context initializer classes defined at the given level
     * will be merged with those defined in higher levels of the class hierarchy.
     *
     * @param configAttributesList the list of configuration attributes to process; must
     * not be {@code null} or <em>empty</em>; must be ordered <em>bottom-up</em>
     * (i.e., as if we were traversing up the class hierarchy)
     * @return the set of merged context initializer classes, including those from
     * superclasses if appropriate (never {@code null})
     * @since 3.2
     */
    static Set<Class<? extends ApplicationContextInitializer<?>>> resolveInitializerClasses(
            List<ContextConfigurationAttributes> configAttributesList) {
        Assert.notEmpty(configAttributesList, "ContextConfigurationAttributes list must not be empty");

        final Set<Class<? extends ApplicationContextInitializer<?>>> initializerClasses = //
                new HashSet<>();

        for (ContextConfigurationAttributes configAttributes : configAttributesList) {
            if (logger.isTraceEnabled()) {
                logger.trace(
                        String.format("Processing context initializers for context configuration attributes %s",
                                configAttributes));
            }

            initializerClasses.addAll(Arrays.asList(configAttributes.getInitializers()));

            if (!configAttributes.isInheritInitializers()) {
                break;
            }
        }

        return initializerClasses;
    }

}