com.linecorp.armeria.client.ClientInvocationHandler.java Source code

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Here is the source code for com.linecorp.armeria.client.ClientInvocationHandler.java

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/*
 * Copyright 2015 LINE Corporation
 *
 * LINE Corporation 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 com.linecorp.armeria.client;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.UndeclaredThrowableException;
import java.net.URI;
import java.nio.channels.ClosedChannelException;

import com.linecorp.armeria.common.ServiceInvocationContext;

import io.netty.channel.EventLoop;
import io.netty.channel.EventLoopGroup;
import io.netty.util.concurrent.Future;

final class ClientInvocationHandler implements InvocationHandler {

    private static final Object[] NO_ARGS = new Object[0];

    private final EventLoopGroup eventLoopGroup;
    private final URI uri;
    private final Class<?> interfaceClass;
    private final Client client;
    private final ClientOptions options;

    ClientInvocationHandler(EventLoopGroup eventLoopGroup, URI uri, Class<?> interfaceClass, Client client,
            ClientOptions options) {

        this.eventLoopGroup = eventLoopGroup;
        this.uri = uri;
        this.interfaceClass = interfaceClass;
        this.client = client;
        this.options = options;
    }

    EventLoopGroup eventLoopGroup() {
        return eventLoopGroup;
    }

    URI uri() {
        return uri;
    }

    Class<?> interfaceClass() {
        return interfaceClass;
    }

    Client client() {
        return client;
    }

    private RemoteInvoker invoker() {
        return client.invoker();
    }

    private ClientCodec codec() {
        return client.codec();
    }

    ClientOptions options() {
        return options;
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        final Class<?> declaringClass = method.getDeclaringClass();
        if (declaringClass == Object.class) {
            // Handle the methods in Object
            return invokeObjectMethod(proxy, method, args);
        }

        assert declaringClass == interfaceClass;
        // Handle the methods in the interface.
        return invokeClientMethod(method, args);
    }

    private Object invokeObjectMethod(Object proxy, Method method, Object[] args) {
        final String methodName = method.getName();

        switch (methodName) {
        case "toString":
            return interfaceClass.getSimpleName() + '(' + uri + ')';
        case "hashCode":
            return System.identityHashCode(proxy);
        case "equals":
            return proxy == args[0];
        default:
            throw new Error("unknown method: " + methodName);
        }
    }

    private Object invokeClientMethod(Method method, Object[] args) throws Throwable {
        if (args == null) {
            args = NO_ARGS;
        }

        try {
            Future<Object> resultFuture = invoker().invoke(eventLoop(), uri, options, codec(), method, args);
            if (codec().isAsyncClient()) {
                return method.getReturnType().isInstance(resultFuture) ? resultFuture : null;
            } else {
                return resultFuture.sync().getNow();
            }
        } catch (ClosedChannelException ignored) {
            throw ClosedSessionException.INSTANCE;
        }
    }

    private EventLoop eventLoop() {
        return ServiceInvocationContext.mapCurrent(ServiceInvocationContext::eventLoop, eventLoopGroup::next);
    }
}