/*

 * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/**

 * @test

 * @library modules

 * @build bananascript/*

 * @compile src/pearscript/org/pear/PearScriptEngineFactory.java

 *          src/pearscript/org/pear/PearScript.java

 * @run testng/othervm Basic

 * @summary Basic test for ServiceLoader with a provider deployed as a module.

 */

import java.lang.module.Configuration;

import java.lang.module.ModuleFinder;

import java.lang.reflect.Layer;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.nio.file.StandardCopyOption;

import java.util.*;

import java.util.ServiceLoader.Provider;

import java.util.stream.Collectors;

import javax.script.ScriptEngineFactory;

import org.testng.annotations.Test;

import org.testng.annotations.BeforeTest;

import static org.testng.Assert.*;

/**

 * Basic test for ServiceLoader. The test make use of two service providers:

 * 1. BananaScriptEngine - a ScriptEngineFactory deployed as a module on the

 *    module path. It implementations a singleton via the public static

 *    provider method.

 * 2. PearScriptEngine - a ScriptEngineFactory deployed on the class path

 *    with a service configuration file.

 */

public class Basic {

    // Copy the services configuration file for "pearscript" into place.

    @BeforeTest

    public void setup() throws Exception {

        Path src = Paths.get(System.getProperty("test.src", ""));

        Path classes = Paths.get(System.getProperty("test.classes", ""));

        String st = ScriptEngineFactory.class.getName();

        Path config = Paths.get("META-INF", "services", st);

        Path source = src.resolve("src").resolve("pearscript").resolve(config);

        Path target = classes.resolve(config);

        Files.createDirectories(target.getParent());

        Files.copy(source, target, StandardCopyOption.REPLACE_EXISTING);

    }

    /**

     * Basic test of iterator() to ensure that providers located as modules

     * and on the class path are found.

     */

    @Test

    public void testIterator() {

        ServiceLoader<ScriptEngineFactory> loader

            = ServiceLoader.load(ScriptEngineFactory.class);

        Set<String> names = collectAll(loader)

                .stream()

                .map(ScriptEngineFactory::getEngineName)

                .collect(Collectors.toSet());

        assertTrue(names.contains("BananaScriptEngine"));

        assertTrue(names.contains("PearScriptEngine"));

    }

    /**

     * Basic test of iterator() to test iteration order. Providers deployed

     * as named modules should be found before providers deployed on the class

     * path.

     */

    @Test

    public void testIteratorOrder() {

        ServiceLoader<ScriptEngineFactory> loader

            = ServiceLoader.load(ScriptEngineFactory.class);

        boolean foundUnnamed = false;

        for (ScriptEngineFactory factory : collectAll(loader)) {

            if (factory.getClass().getModule().isNamed()) {

                if (foundUnnamed) {

                    assertTrue(false, "Named module element after unnamed");

                }

            } else {

                foundUnnamed = true;

            }

        }

    }

    /**

     * Basic test of Provider::type

     */

    @Test

    public void testProviderType() {

        Set<String> types = ServiceLoader.load(ScriptEngineFactory.class)

                .stream()

                .map(Provider::type)

                .map(Class::getName)

                .collect(Collectors.toSet());

        assertTrue(types.contains("org.banana.BananaScriptEngineFactory"));

        assertTrue(types.contains("org.pear.PearScriptEngineFactory"));

    }

    /**

     * Basic test of Provider::get

     */

    @Test

    public void testProviderGet() {

        Set<String> names = ServiceLoader.load(ScriptEngineFactory.class)

                .stream()

                .map(Provider::get)

                .map(ScriptEngineFactory::getEngineName)

                .collect(Collectors.toSet());

        assertTrue(names.contains("BananaScriptEngine"));

        assertTrue(names.contains("PearScriptEngine"));

    }

    /**

     * Basic test of the public static provider method. BananaScriptEngine

     * defines a provider method that returns the same instance.

     */

    @Test

    public void testSingleton() {

        Optional<Provider<ScriptEngineFactory>> oprovider

            = ServiceLoader.load(ScriptEngineFactory.class)

                .stream()

                .filter(p -> p.type().getName().equals("org.banana.BananaScriptEngineFactory"))

                .findFirst();

        assertTrue(oprovider.isPresent());

        Provider<ScriptEngineFactory> provider = oprovider.get();

        // invoke Provider::get twice

        ScriptEngineFactory factory1 = provider.get();

        ScriptEngineFactory factory2 = provider.get();

        assertTrue(factory1 == factory2);

    }

    /**

     * Basic test of stream() to ensure that elements for providers in named

     * modules come before elements for providers in unnamed modules.

     */

    @Test

    public void testStreamOrder() {

        List<Class<?>> types = ServiceLoader.load(ScriptEngineFactory.class)

                .stream()

                .map(Provider::type)

                .collect(Collectors.toList());

        boolean foundUnnamed = false;

        for (Class<?> factoryClass : types) {

            if (factoryClass.getModule().isNamed()) {

                if (foundUnnamed) {

                    assertTrue(false, "Named module element after unnamed");

                }

            } else {

                foundUnnamed = true;

            }

        }

    }

    /**

     * Basic test of ServiceLoader.findFirst()

     */

    @Test

    public void testFindFirst() {

        Optional<ScriptEngineFactory> ofactory

            = ServiceLoader.load(ScriptEngineFactory.class).findFirst();

        assertTrue(ofactory.isPresent());

        ScriptEngineFactory factory = ofactory.get();

        assertTrue(factory.getClass().getModule().isNamed());

        class S { }

        assertFalse(ServiceLoader.load(S.class).findFirst().isPresent());

    }

    /**

     * Basic test ServiceLoader.load specifying the platform class loader.

     * The providers on the module path and class path should not be located.

     */

    @Test

    public void testWithPlatformClassLoader() {

        ClassLoader pcl = ClassLoader.getPlatformClassLoader();

        // iterator

        ServiceLoader<ScriptEngineFactory> loader

                = ServiceLoader.load(ScriptEngineFactory.class, pcl);

        Set<String> names = collectAll(loader)

                .stream()

                .map(ScriptEngineFactory::getEngineName)

                .collect(Collectors.toSet());

        assertFalse(names.contains("BananaScriptEngine"));

        assertFalse(names.contains("PearScriptEngine"));

        // stream

        names = ServiceLoader.load(ScriptEngineFactory.class, pcl)

                .stream()

                .map(Provider::get)

                .map(ScriptEngineFactory::getEngineName)

                .collect(Collectors.toSet());

        assertFalse(names.contains("BananaScriptEngine"));

        assertFalse(names.contains("PearScriptEngine"));

    }

    /**

     * Basic test of ServiceLoader.load, using the class loader for

     * a module in a custom layer as the context.

     */

    @Test

    public void testWithCustomLayer1() {

        Layer layer = createCustomLayer("bananascript");

        ClassLoader loader = layer.findLoader("bananascript");

        List<ScriptEngineFactory> providers

            = collectAll(ServiceLoader.load(ScriptEngineFactory.class, loader));

        // should have at least 2 x bananascript + pearscript

        assertTrue(providers.size() >= 3);

        // first element should be the provider in the custom layer

        ScriptEngineFactory factory = providers.get(0);

        assertTrue(factory.getClass().getClassLoader() == loader);

        assertTrue(factory.getClass().getModule().getLayer() == layer);

        assertTrue(factory.getEngineName().equals("BananaScriptEngine"));

        // remainder should be the boot layer

        providers.remove(0);

        Set<String> names = providers.stream()

                .map(ScriptEngineFactory::getEngineName)

                .collect(Collectors.toSet());

        assertTrue(names.contains("BananaScriptEngine"));

        assertTrue(names.contains("PearScriptEngine"));

    }

    /**

     * Basic test of ServiceLoader.load using a custom Layer as the context.

     */

    @Test

    public void testWithCustomLayer2() {

        Layer layer = createCustomLayer("bananascript");

        List<ScriptEngineFactory> factories

            = collectAll(ServiceLoader.load(layer, ScriptEngineFactory.class));

        // should have at least 2 x bananascript

        assertTrue(factories.size() >= 2);

        // first element should be the provider in the custom layer

        ScriptEngineFactory factory = factories.get(0);

        assertTrue(factory.getClass().getModule().getLayer() == layer);

        assertTrue(factory.getEngineName().equals("BananaScriptEngine"));

        // remainder should be the boot layer

        factories.remove(0);

        Set<String> names = factories.stream()

                .map(ScriptEngineFactory::getEngineName)

                .collect(Collectors.toSet());

        assertTrue(names.contains("BananaScriptEngine"));

        assertFalse(names.contains("PearScriptEngine"));

    }

    /**

     * Basic test of ServiceLoader.load with a tree of layers.

     *

     * Test scenario:

     * - boot layer contains "bananascript", maybe other script engines

     * - layer1, with boot layer as parent, contains "bananascript"

     * - layer2, with boot layer as parent, contains "bananascript"

     * - layer3, with layer1 ad layer as parents, contains "bananascript"

     *

     * ServiceLoader should locate all 4 script engine factories in DFS order.

     */

    @Test

    public void testWithCustomLayer3() {

        Layer bootLayer = Layer.boot();

        Configuration cf0 = bootLayer.configuration();

        // boot layer should contain "bananascript"

        List<ScriptEngineFactory> factories

            = collectAll(ServiceLoader.load(bootLayer, ScriptEngineFactory.class));

        int countInBootLayer = factories.size();

        assertTrue(countInBootLayer >= 1);

        assertTrue(factories.stream()

                .map(p -> p.getEngineName())

                .filter("BananaScriptEngine"::equals)

                .findAny()

                .isPresent());

        ClassLoader scl = ClassLoader.getSystemClassLoader();

        Path dir = Paths.get(System.getProperty("test.classes", "."), "modules");

        ModuleFinder finder = ModuleFinder.of(dir);

        // layer1

        Layer layer1 = bootLayer.defineModulesWithOneLoader(cf1, scl);

        assertTrue(layer1.modules().size() == 1);

        // layer2

        Layer layer2 = bootLayer.defineModulesWithOneLoader(cf2, scl);

        assertTrue(layer2.modules().size() == 1);

        // layer3 with layer1 and layer2 as parents

                List.of(cf1, cf2),

                ModuleFinder.of(),

                Set.of());

        Layer layer3 = Layer.defineModulesWithOneLoader(cf3, List.of(layer1, layer2), scl).layer();

        assertTrue(layer3.modules().size() == 1);

        // class loaders

        ClassLoader loader1 = layer1.findLoader("bananascript");

        ClassLoader loader2 = layer2.findLoader("bananascript");

        ClassLoader loader3 = layer3.findLoader("bananascript");

        assertTrue(loader1 != loader2);

        assertTrue(loader1 != loader3);

        assertTrue(loader2 != loader3);

        // load all factories with layer3 as the context

        factories = collectAll(ServiceLoader.load(layer3, ScriptEngineFactory.class));

        int count = factories.size();

        assertTrue(count == countInBootLayer + 3);

        // the ordering should be layer3, layer1, boot layer, layer2

        ScriptEngineFactory factory = factories.get(0);

        assertTrue(factory.getClass().getModule().getLayer() == layer3);

        assertTrue(factory.getClass().getClassLoader() == loader3);

        assertTrue(factory.getEngineName().equals("BananaScriptEngine"));

        factory = factories.get(1);

        assertTrue(factory.getClass().getModule().getLayer() == layer1);

        assertTrue(factory.getClass().getClassLoader() == loader1);

        assertTrue(factory.getEngineName().equals("BananaScriptEngine"));

        // boot layer "bananascript" and maybe other factories

        int last = count -1;

        boolean found = false;

        for (int i=2; i<last; i++) {

            factory = factories.get(i);

            assertTrue(factory.getClass().getModule().getLayer() == bootLayer);

            if (factory.getEngineName().equals("BananaScriptEngine")) {

                assertFalse(found);

                found = true;

            }

        }

        assertTrue(found);

        factory = factories.get(last);

        assertTrue(factory.getClass().getModule().getLayer() == layer2);

        assertTrue(factory.getClass().getClassLoader() == loader2);

        assertTrue(factory.getEngineName().equals("BananaScriptEngine"));

    }

    // -- nulls --

    @Test(expectedExceptions = { NullPointerException.class })

    public void testLoadNull1() {

        ServiceLoader.load(null);

    }

    @Test(expectedExceptions = { NullPointerException.class })

    public void testLoadNull2() {

        ServiceLoader.load((Class<?>) null, ClassLoader.getSystemClassLoader());

    }

    @Test(expectedExceptions = { NullPointerException.class })

    public void testLoadNull3() {

        class S { }

        ServiceLoader.load((Layer) null, S.class);

    }

    @Test(expectedExceptions = { NullPointerException.class })

    public void testLoadNull4() {

        ServiceLoader.load(Layer.empty(), null);

    }

    @Test(expectedExceptions = { NullPointerException.class })

    public void testLoadNull5() {

        ServiceLoader.loadInstalled(null);

    }

    /**

     * Create a custom Layer by resolving the given module names. The modules

     * are located in the {@code ${test.classes}/modules} directory.

     */

    private Layer createCustomLayer(String... modules) {

        Path dir = Paths.get(System.getProperty("test.classes", "."), "modules");

        ModuleFinder finder = ModuleFinder.of(dir);

        Set<String> roots = new HashSet<>();

        Collections.addAll(roots, modules);

        Layer bootLayer = Layer.boot();

        Configuration parent = bootLayer.configuration();

        ClassLoader scl = ClassLoader.getSystemClassLoader();

        Layer layer = bootLayer.defineModulesWithOneLoader(cf, scl);

        assertTrue(layer.modules().size() == 1);

        return layer;

    }

    private <E> List<E> collectAll(ServiceLoader<E> loader) {

        List<E> list = new ArrayList<>();

        Iterator<E> iterator = loader.iterator();

        while (iterator.hasNext()) {

            list.add(iterator.next());

        }

        return list;

    }

}