gradle-master/subprojects/plugins/src/main/java/org/gradle/api/plugins/internal/JavaPluginHelper.java
/*
 * Copyright 2023 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.gradle.api.plugins.internal;

import org.gradle.api.GradleException;
import org.gradle.api.Project;
import org.gradle.api.component.SoftwareComponent;
import org.gradle.api.internal.tasks.JvmConstants;
import org.gradle.api.plugins.JavaPlugin;
import org.gradle.api.plugins.JvmTestSuitePlugin;
import org.gradle.api.plugins.jvm.JvmTestSuite;
import org.gradle.jvm.component.internal.JvmSoftwareComponentInternal;
import org.gradle.testing.base.TestSuite;
import org.gradle.testing.base.TestingExtension;

/**
 * Utility class intended for use only when the {@link JavaPlugin} is applied.
 * This class exists to avoid adding these methods to the {@code JavaPlugin} itself,
 * and thus avoids adding these methods to the public API.
 */
public class JavaPluginHelper {

    private JavaPluginHelper() {
        // Private to prevent instantiation.
    }

    /**
     * Gets the main Java component. This method assumes the Java plugin is applied.
     *
     * @throws GradleException If the {@code java} component does not exist.
     */
    public static JvmSoftwareComponentInternal getJavaComponent(Project project) {
        SoftwareComponent component = project.getComponents().findByName(JvmConstants.JAVA_COMPONENT_NAME);

        if (!(component instanceof JvmSoftwareComponentInternal)) {
            throw new GradleException("The Java plugin must be applied to access the java component.");
        }

        return (JvmSoftwareComponentInternal) component;
    }

    /**
     * Gets the default test suite. This method assumes the Java plugin is applied.
     *
     * @throws GradleException If the default test suite does not exist.
     */
    public static JvmTestSuite getDefaultTestSuite(Project project) {
        String message = "The Java plugin must be applied to access the default test suite.";

        TestingExtension testing = project.getExtensions().findByType(TestingExtension.class);
        if (testing == null) {
            throw new GradleException(message);
        }

        TestSuite defaultTestSuite = testing.getSuites().findByName(JvmTestSuitePlugin.DEFAULT_TEST_SUITE_NAME);
        if (!(defaultTestSuite instanceof JvmTestSuite)) {
            throw new GradleException(message);
        }

        return (JvmTestSuite) defaultTestSuite;
    }
}
