surefire-providers/surefire-junit-platform/src/main/java/org/apache/maven/surefire/junitplatform/LazyLauncher.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.maven.surefire.junitplatform;

import org.apache.maven.surefire.api.util.ReflectionUtils;
import org.junit.platform.launcher.Launcher;
import org.junit.platform.launcher.LauncherDiscoveryListener;
import org.junit.platform.launcher.LauncherDiscoveryRequest;
import org.junit.platform.launcher.TestExecutionListener;
import org.junit.platform.launcher.TestPlan;
import org.junit.platform.launcher.core.LauncherFactory;

/**
 * Launcher proxy which delays the most possible the initialization of the real JUnit
 * Launcher in order to avoid stream/stdout corruption due to early logging.
 */
class LazyLauncher implements Launcher, AutoCloseable {
    private AutoCloseable launcherSession;

    private Launcher launcher;

    @Override
    public void registerLauncherDiscoveryListeners(LauncherDiscoveryListener... listeners) {
        launcher().registerLauncherDiscoveryListeners(listeners);
    }

    @Override
    public void registerTestExecutionListeners(TestExecutionListener... testExecutionListeners) {
        launcher().registerTestExecutionListeners(testExecutionListeners);
    }

    @Override
    public TestPlan discover(LauncherDiscoveryRequest launcherDiscoveryRequest) {
        return launcher().discover(launcherDiscoveryRequest);
    }

    @Override
    public void execute(
            LauncherDiscoveryRequest launcherDiscoveryRequest, TestExecutionListener... testExecutionListeners) {
        launcher().execute(launcherDiscoveryRequest, testExecutionListeners);
    }

    @Override
    public void execute(TestPlan testPlan, TestExecutionListener... listeners) {
        launcher().execute(testPlan, listeners);
    }

    private Launcher launcher() {
        if (launcher == null) {
            try {
                Class<?> sessionClass = Class.forName("org.junit.platform.launcher.LauncherSession");
                launcherSession = ReflectionUtils.invokeGetter(LauncherFactory.class, null, "openSession");
                launcher = ReflectionUtils.invokeGetter(sessionClass, launcherSession, "getLauncher");
            } catch (ClassNotFoundException e) {
                launcher = LauncherFactory.create();
            }
        }
        return launcher;
    }

    @Override
    public void close() throws Exception {
        if (launcherSession != null) {
            launcherSession.close();
            launcherSession = null;
        }
        launcher = null;
    }
}