RequestDispatcher.java

/*******************************************************************************
 * Copyright (c) 2012-2017 Codenvy, S.A.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   Codenvy, S.A. - initial API and implementation
 *******************************************************************************/
package org.eclipse.che.api.core.jsonrpc.commons;

import org.slf4j.Logger;

import javax.inject.Inject;
import javax.inject.Singleton;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static org.slf4j.LoggerFactory.getLogger;

/**
 * Dispatches incoming JSON RPC requests and notifications. If during
 * dispatching happens any kind of error related to JSON RPC it throws
 * appropriate exception {@link JsonRpcException}.
 */
@Singleton
public class RequestDispatcher {
    private final static Logger LOGGER = getLogger(RequestDispatcher.class);

    private final RequestHandlerManager requestHandlerManager;

    @Inject
    public RequestDispatcher(RequestHandlerManager requestHandlerManager) {
        this.requestHandlerManager = requestHandlerManager;
    }

    public void dispatch(String endpointId, JsonRpcRequest request) throws JsonRpcException {
        checkNotNull(endpointId, "Endpoint ID must not be null");
        checkArgument(!endpointId.isEmpty(), "Endpoint ID must not be empty");
        checkNotNull(request, "Request must not be null");

        LOGGER.debug("Dispatching request: " + request + ", endpoint: " + endpointId);

        String method = request.getMethod();

        JsonRpcParams params = request.getParams();

        if (request.hasId()) {
            LOGGER.debug("Request has ID");
            String requestId = request.getId();
            checkRequestHandlerRegistration(method, requestId);
            requestHandlerManager.handle(endpointId, requestId, method, params);
        } else {
            LOGGER.debug("Request has no ID -> it is a notification");
            checkNotificationHandlerRegistration(method);
            requestHandlerManager.handle(endpointId, method, params);
        }
    }

    private void checkNotificationHandlerRegistration(String method) throws JsonRpcException {
        if (!requestHandlerManager.isRegistered(method)) {
            LOGGER.error("No corresponding to method '" + method + "' handler is registered");
            throw new JsonRpcException(-32601, "Method '" + method + "' not registered");
        }
    }

    private void checkRequestHandlerRegistration(String method, String requestId) throws JsonRpcException {
        if (!requestHandlerManager.isRegistered(method)) {
            LOGGER.error("No corresponding to method '" + method + "' handler is registered");
            throw new JsonRpcException(-32601, "Method '" + method + "' not registered", requestId);
        }
    }
}