vaadin-framework/server/src/test/java/com/vaadin/server/AbstractClientConnectorTest.java

package com.vaadin.server;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;

import java.io.IOException;
import java.io.InputStream;
import java.lang.ref.WeakReference;
import java.lang.reflect.Field;
import java.net.URL;
import java.util.Map;

import org.apache.commons.io.IOUtils;
import org.junit.Test;
import org.mockito.Mockito;

import com.vaadin.shared.MouseEventDetails;
import com.vaadin.shared.communication.FieldRpc.BlurServerRpc;
import com.vaadin.shared.ui.ClickRpc;

/**
 * We test that AbstractClientConnector has a suitable isThis method which is
 * needed to correctly perform an equals check between a proxy and it's
 * underlying instance.
 *
 * @author Vaadin Ltd
 */
public class AbstractClientConnectorTest {

    @Test
    public void registerRPCMultiInterfaceTest() {
        AbstractClientConnector mock = mock(AbstractClientConnector.class);
        MultiServerRpcMock implementation = new MultiServerRpcMock();
        Mockito.doCallRealMethod().when(mock).registerRpc(implementation);
        try {
            mock.registerRpc(implementation);
            fail("expected exception");
        } catch (Exception expected) {
            assertEquals(
                    "Use registerRpc(T implementation, Class<T> rpcInterfaceType) "
                            + "if the Rpc implementation implements more than one interface",
                    expected.getMessage());
        }
    }

    @Test
    public void registerRPCInterfaceTest() {
        AbstractClientConnector mock = mock(AbstractClientConnector.class);
        ServerRpcMock implementation = new ServerRpcMock();
        Mockito.doCallRealMethod().when(mock).registerRpc(implementation);
        mock.registerRpc(implementation);
        verify(mock, times(1)).registerRpc(implementation, ClickRpc.class);
    }

    @Test
    public void registerRPCInterfaceLastTest() {
        AbstractClientConnector mock = mock(AbstractClientConnector.class);
        ServerRpcLastMock implementation = new ServerRpcLastMock();
        Mockito.doCallRealMethod().when(mock).registerRpc(implementation);
        mock.registerRpc(implementation);
        verify(mock, times(1)).registerRpc(implementation, ClickRpc.class);
    }

    @Test
    public void stateTypeCacheDoesNotLeakMemory()
            throws IllegalArgumentException, IllegalAccessException,
            NoSuchFieldException, SecurityException, InterruptedException,
            ClassNotFoundException {
        Field stateTypeCacheField = AbstractClientConnector.class
                .getDeclaredField("STATE_TYPE_CACHE");
        stateTypeCacheField.setAccessible(true);
        Map<Class<?>, ?> stateTypeCache = (Map<Class<?>, ?>) stateTypeCacheField
                .get(null);

        WeakReference<Class<?>> classRef = loadClass(
                "com.vaadin.server.AbstractClientConnector");
        stateTypeCache.put(classRef.get(), null);
        int size = stateTypeCache.size();
        assertNotNull("Class should not yet be garbage collected",
                classRef.get());

        for (int i = 0; i < 100; ++i) {
            System.gc();
            if (stateTypeCache.size() < size) {
                break;
            }
            Thread.sleep(100);
        }
        assertTrue(stateTypeCache.size() < size);
        assertNull("Class should be garbage collected", classRef.get());
    }

    private WeakReference<Class<?>> loadClass(String name)
            throws ClassNotFoundException {
        ClassLoader loader = new TestClassLoader();
        Class<?> loaded = loader.loadClass(name);
        return new WeakReference<>(loaded);
    }

    private class ServerRpcLastMock
            implements Comparable<ServerRpcLastMock>, ClickRpc {
        private static final long serialVersionUID = -2822356895755286180L;

        @Override
        public void click(MouseEventDetails mouseDetails) {
        }

        @Override
        public int compareTo(ServerRpcLastMock o) {
            return 0;
        }

    }

    private class ServerRpcMock implements ClickRpc {
        private static final long serialVersionUID = 2822356895755286180L;

        @Override
        public void click(MouseEventDetails mouseDetails) {
        }

    }

    private class MultiServerRpcMock implements ClickRpc, BlurServerRpc {

        private static final long serialVersionUID = -7611999715560330373L;

        @Override
        public void blur() {

        }

        @Override
        public void click(MouseEventDetails mouseDetails) {

        }

    }

    private static class TestClassLoader extends ClassLoader {

        @Override
        public Class<?> loadClass(String name) throws ClassNotFoundException {
            if (!name.startsWith("com.vaadin.")) {
                return super.loadClass(name);
            }
            String path = name.replace('.', '/').concat(".class");
            URL resource = Thread.currentThread().getContextClassLoader()
                    .getResource(path);
            try (InputStream stream = resource.openStream()) {
                byte[] bytes = IOUtils.toByteArray(stream);
                return defineClass(name, bytes, 0, bytes.length);
            } catch (IOException e) {
                throw new ClassNotFoundException();
            }
        }
    }

}