Java/FactoryRegistryTest.java

/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 *
 *    (C) 2005-2008, Open Source Geospatial Foundation (OSGeo)
 *
 *    This library is free software; you can redistribute it and/or
 *    modify it under the terms of the GNU Lesser General Public
 *    License as published by the Free Software Foundation;
 *    version 2.1 of the License.
 *
 *    This library 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
 *    Lesser General Public License for more details.
 */
package org.geotools.util.factory;

import static java.util.stream.Collectors.toList;
import static java.util.stream.Collectors.toSet;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertNotSame;
import static org.junit.Assert.assertSame;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;

import java.io.IOException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Collections;
import java.util.List;
import java.util.Optional;
import java.util.Set;
import java.util.stream.Stream;
import org.junit.Before;
import org.junit.Ignore;
import org.junit.Test;

/**
 * Tests {@link org.geotools.util.factory.FactoryRegistry} implementation.
 *
 * @version $Id$
 * @author Martin Desruisseaux
 */
public final class FactoryRegistryTest {
    /**
     * Ensures that class {@link org.geotools.util.factory.Hints} is loaded before {@link
     * DummyFactory}. It is not needed for normal execution, but Maven seems to mess with class
     * loaders.
     */
    @Before
    public void ensureHintsLoaded() {
        assertNotNull(Hints.DATUM_FACTORY.toString());
    }

    /**
     * Creates the factory registry to test. The tests performed in this method are more J2SE tests
     * than Geotools implementation tests. We basically just ensure that we have setup the service
     * registry properly.
     *
     * <p>Factories are specified in arguments as {@link org.geotools.util.factory.Factory} objects
     * in order to avoid the {@link DummyClass} to be initialized before {@link
     * org.geotools.util.factory.Hints}. This is not a problem for normal execution, but Maven seems
     * to mess with class loaders.
     *
     * @param creator {@code true} if the registry should be an instance of {@link
     *     org.geotools.util.factory.FactoryCreator}.
     */
    @SuppressWarnings("PMD.UnusedPrivateMethod") // PMD getting confused here?
    private FactoryRegistry getRegistry(
            final boolean creator,
            final Factory factory1,
            final Factory factory2,
            final Factory factory3) {
        @SuppressWarnings("unchecked")
        final Set<Class<?>> categories = Collections.singleton(DummyFactory.class);
        // The above line fails without the cast, I don't know why...
        final FactoryRegistry registry;
        if (creator) {
            registry = new FactoryCreator(categories);
        } else {
            registry = new FactoryRegistry(categories);
        }
        registry.registerFactory(factory1);
        registry.registerFactory(factory2);
        registry.registerFactory(factory3);
        assertTrue(
                registry.setOrdering(
                        DummyFactory.class, (DummyFactory) factory1, (DummyFactory) factory2));
        assertTrue(
                registry.setOrdering(
                        DummyFactory.class, (DummyFactory) factory2, (DummyFactory) factory3));
        assertTrue(
                registry.setOrdering(
                        DummyFactory.class, (DummyFactory) factory1, (DummyFactory) factory3));

        final List<?> factories =
                registry.getFactories(DummyFactory.class, null, null).collect(toList());
        assertTrue(factories.contains(factory1));
        assertTrue(factories.contains(factory2));
        assertTrue(factories.contains(factory3));
        assertTrue(factories.indexOf(factory1) < factories.indexOf(factory2));
        assertTrue(factories.indexOf(factory2) < factories.indexOf(factory3));
        return registry;
    }

    /**
     * Tests the {@link org.geotools.util.factory.FactoryRegistry#getProvider} method. Note that the
     * tested method do not create any new factory. If no registered factory matching the hints is
     * found, an exception is expected. <br>
     * <br>
     * Three factories are initially registered: factory #1, #2 and #3.
     *
     * <p>Factory #1 has no dependency. Factory #2 uses factory #1. Factory #3 uses factory #2,
     * which implies an indirect dependency to factory #1.
     *
     * <p>Additionnaly, factory #1 uses a KEY_INTERPOLATION hint.
     */
    @Test
    public void testGetProvider() {
        final Hints.Key key = DummyFactory.DUMMY_FACTORY;
        final DummyFactory factory1 = new DummyFactory.Example1();
        final DummyFactory factory2 = new DummyFactory.Example2();
        final DummyFactory factory3 = new DummyFactory.Example3();
        final FactoryRegistry registry = getRegistry(false, factory1, factory2, factory3);
        // ------------------------------------------------
        //     PART 1: SIMPLE HINT (not a Factory hint)
        // ------------------------------------------------
        /*
         * No hints. The fist factory should be selected.
         */
        Hints hints = null;
        DummyFactory factory = registry.getFactory(DummyFactory.class, null, hints, key);
        assertSame("No preferences; should select the first factory. ", factory1, factory);
        /*
         * A hint compatible with one of our factories. Factory #1 declares explicitly that it uses
         * a bilinear interpolation, which is compatible with user's hints. All other factories are
         * indifferent. Since factory #1 is the first one in the list, it should be selected.
         */
        hints = new Hints(Hints.KEY_INTERPOLATION, Hints.VALUE_INTERPOLATION_BILINEAR);
        factory = registry.getFactory(DummyFactory.class, null, hints, key);
        assertSame("First factory matches; it should be selected. ", factory1, factory);
        /*
         * A hint incompatible with all our factories. Factory #1 is the only one to defines
         * explicitly a KEY_INTERPOLATION hint, but all other factories depend on factory #1
         * either directly (factory #2) or indirectly (factory #3, which depends on #2).
         */
        hints = new Hints(Hints.KEY_INTERPOLATION, Hints.VALUE_INTERPOLATION_BICUBIC);
        try {
            factory = registry.getFactory(DummyFactory.class, null, hints, key);
            fail("Found factory " + factory + ", while the hint should have been rejected.");
        } catch (FactoryNotFoundException exception) {
            // This is the expected exception. Continue...
        }
        /*
         * Add a new factory implementation, and try again with exactly the same hints
         * than the previous test. This time, the new factory should be selected since
         * this one doesn't have any dependency toward factory #1.
         */
        final DummyFactory factory4 = new DummyFactory.Example4();
        registry.registerFactory(factory4);
        assertTrue(registry.setOrdering(DummyFactory.class, factory1, factory4));
        factory = registry.getFactory(DummyFactory.class, null, hints, key);
        assertSame("The new factory should be selected. ", factory4, factory);

        // ----------------------------
        //     PART 2: FACTORY HINT
        // ----------------------------
        /*
         * Trivial case: user gives explicitly a factory instance.
         */
        DummyFactory explicit = new DummyFactory.Example3();
        hints = new Hints(DummyFactory.DUMMY_FACTORY, explicit);
        factory = registry.getFactory(DummyFactory.class, null, hints, key);
        assertSame("The user-specified factory should have been selected. ", explicit, factory);
        /*
         * User specifies the expected implementation class rather than an instance.
         */
        hints = new Hints(DummyFactory.DUMMY_FACTORY, DummyFactory.Example2.class);
        factory = registry.getFactory(DummyFactory.class, null, hints, key);
        assertSame("Factory of class #2 were requested. ", factory2, factory);
        /*
         * Same as above, but with classes specified in an array.
         */
        hints =
                new Hints(
                        DummyFactory.DUMMY_FACTORY,
                        new Class<?>[] {DummyFactory.Example3.class, DummyFactory.Example2.class});
        factory = registry.getFactory(DummyFactory.class, null, hints, key);
        assertSame("Factory of class #3 were requested. ", factory3, factory);
        /*
         * The following hint should be ignored by factory #1, since this factory doesn't have
         * any dependency to the INTERNAL_FACTORY hint. Since factory #1 is first in the ordering,
         * it should be selected.
         */
        hints = new Hints(DummyFactory.INTERNAL_FACTORY, DummyFactory.Example2.class);
        factory = registry.getFactory(DummyFactory.class, null, hints, key);
        assertSame("Expected factory #1. ", factory1, factory);
        /*
         * If the user really wants some factory that do have a dependency to factory #2, he should
         * specifies in a DUMMY_FACTORY hint the implementation classes (or a common super-class or
         * interface) that do care about the INTERNAL_FACTORY hint. Note that this extra step should
         * not be a big deal in most real application, because:
         *
         *  1) Either all implementations have this dependency (for example it would be
         *     unusual to see a DatumAuthorityFactory without a DatumFactory dependency);
         *
         *  2) or the user really know the implementation he wants (for example if he specifies a
         *     JTS CoordinateSequenceFactory, he probably wants to use the JTS GeometryFactory).
         *
         * In the particular case of this test suite, this extra step would not be needed
         * neither if factory #1 was last in the ordering rather than first.
         */
        final Hints implementations =
                new Hints(
                        DummyFactory.DUMMY_FACTORY,
                        new Class[] {DummyFactory.Example2.class, DummyFactory.Example3.class});
        /*
         * Now search NOT for factory #1, but rather for a factory using #1 internally.
         * This is the case of factory #2.
         */
        hints = new Hints(DummyFactory.INTERNAL_FACTORY, DummyFactory.Example1.class);
        hints.add(implementations);
        factory = registry.getFactory(DummyFactory.class, null, hints, key);
        assertSame("Expected a factory using #1 internally. ", factory2, factory);
    }

    /**
     * Tests the {@link org.geotools.util.factory.FactoryCreator#getProvider} method. This test
     * tries again the cases that was expected to throws an exception in {@link #testGetProvider}.
     * But now, those cases are expected to creates automatically new factory instances instead of
     * throwing an exception.
     */
    @Test
    public void testCreateProvider() {
        final Hints.Key key = DummyFactory.DUMMY_FACTORY;
        final DummyFactory factory1 = new DummyFactory.Example1();
        final DummyFactory factory2 = new DummyFactory.Example2();
        final DummyFactory factory3 = new DummyFactory.Example3();
        final FactoryRegistry registry = getRegistry(true, factory1, factory2, factory3);
        /*
         * Same tests than above (at least some of them).
         * See comments in 'testGetProvider()' for explanation.
         */
        Hints hints = new Hints(Hints.KEY_INTERPOLATION, Hints.VALUE_INTERPOLATION_BILINEAR);
        DummyFactory factory = registry.getFactory(DummyFactory.class, null, hints, key);
        assertSame("First factory matches; it should be selected. ", factory1, factory);

        hints = new Hints(DummyFactory.DUMMY_FACTORY, DummyFactory.Example2.class);
        factory = registry.getFactory(DummyFactory.class, null, hints, key);
        assertSame("Factory of class #2 were requested. ", factory2, factory);
        /*
         * The following case was throwing an exception in testGetProvider(). It should fails again
         * here, but for a different reason. FactoryCreator is unable to creates automatically a new
         * factory instance, since we gave no implementation hint and no registered factory have a
         * constructor expecting a Hints argument.
         */
        hints = new Hints(Hints.KEY_INTERPOLATION, Hints.VALUE_INTERPOLATION_BICUBIC);
        try {
            factory = registry.getFactory(DummyFactory.class, null, hints, key);
            fail(
                    "Found or created factory "
                            + factory
                            + ", while it should not have been allowed.");
        } catch (FactoryNotFoundException exception) {
            // This is the expected exception. Continue...
        }
        /*
         * Register a DummyFactory with a constructor expecting a Hints argument, and try again
         * with the same hints. Now it should creates a new factory instance, because we are using
         * FactoryCreator instead of FactoryRegistry and an appropriate constructor is found.
         * Note that an AssertionFailedError should be thrown if the no-argument constructor of
         * Example5 is invoked, since the constructor with a Hints argument should have priority.
         */
        final DummyFactory factory5 = new DummyFactory.Example5(null);
        registry.registerFactory(factory5);
        assertTrue(registry.setOrdering(DummyFactory.class, factory1, factory5));
        factory = registry.getFactory(DummyFactory.class, null, hints, key);
        assertSame(
                "An instance of Factory #5 should have been created.",
                factory5.getClass(),
                factory.getClass());
        assertNotSame("A NEW instance of Factory #5 should have been created", factory5, factory);
        /*
         * Tries again with a class explicitly specified as an implementation hint.
         * It doesn't matter if this class is registered or not.
         */
        hints.put(DummyFactory.DUMMY_FACTORY, DummyFactory.Example4.class);
        factory = registry.getFactory(DummyFactory.class, null, hints, key);
        assertEquals(
                "An instance of Factory #4 should have been created.",
                DummyFactory.Example4.class,
                factory.getClass());
    }

    @Ignore
    @Test
    public void testLookupWithExtendedClasspath() throws IOException {
        URL url = getClass().getResource("foo.jar");
        assertNotNull(url);

        FactoryRegistry reg = new FactoryCreator(DummyInterface.class);
        Stream<DummyInterface> factories = reg.getFactories(DummyInterface.class, false);
        assertFalse(factories.findAny().isPresent());

        try (URLClassLoader cl = new URLClassLoader(new URL[] {url})) {
            GeoTools.addClassLoader(cl);
            reg.scanForPlugins();

            Set<String> classes =
                    reg.getFactories(DummyInterface.class, false)
                            .map(factory -> factory.getClass().getName())
                            .collect(toSet());

            assertEquals(2, classes.size());
            assertTrue(classes.contains("pkg.Foo"));
            assertTrue(classes.contains("org.geotools.util.factory.DummyInterfaceImpl"));
        }
    }

    /** Tests for GEOT-2817 */
    @Test
    public void testLookupWithSameFactoryInTwoClassLoaders()
            throws IOException, ClassNotFoundException {
        // create url to this project's classes
        URL projectClasses = getClass().getResource("/");
        // create 2 classloaders with parent null to avoid delegation to the system class loader !
        // this occurs in reality with split class loader hierarchies (e.g. GWT plugin and
        // some application servers)
        try (URLClassLoader cl1 = new URLClassLoader(new URL[] {projectClasses}, null);
                URLClassLoader cl2 = new URLClassLoader(new URL[] {projectClasses}, null)) {
            // extend with both class loaders
            GeoTools.addClassLoader(cl1);
            GeoTools.addClassLoader(cl2);
            // code below was throwing ClassCastException (before java 7) prior to adding
            // isAssignableFrom() check (line 862)
            for (int i = 0; i < 2; i++) {
                ClassLoader loader = (i == 0 ? cl1 : cl2);
                Class dummy = loader.loadClass("org.geotools.util.factory.DummyInterface");
                FactoryRegistry reg = new FactoryCreator(dummy);
                reg.scanForPlugins();
                // we are mocking with two class loaders, trying to make it type safe will make
                // the factory fail to load the factory
                @SuppressWarnings("unchecked")
                Optional factory = reg.getFactories(dummy, false).findFirst();
                assertTrue(factory.isPresent());
                // factory class should have same class loader as interface
                assertSame(loader, factory.get().getClass().getClassLoader());
            }
        }
    }
}