com.googlecode.jsonrpc4j.JsonRpcMultiServer.java Source code

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/*
The MIT License (MIT)
    
Copyright (c) 2014 jsonrpc4j
    
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
    
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
    
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
 */

package com.googlecode.jsonrpc4j;

import java.lang.reflect.Proxy;
import java.util.HashMap;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

/**
 * A multiple service dispatcher that supports JSON-RPC "method" names
 * that use dot-notation to select a server endpoint.  For example:
 * <pre>
 * {
 *    "jsonrpc": "2.0",
 *    "method": "service.method",
 *    "params": {"foo", "bar"},
 *    "id": 1
 * }
 * </pre>
 * An example of using this class is:
 * <code>
 *    JsonRpcMultiServer rpcServer = new JsonRpcMultiServer();
 *    rpcServer.addService("Foo", new FooService())
 *             .addService("Bar", new BarService());
 * </code>
 * A client can then call a <i>test(String, String)</i> method on the Foo service
 * like this:
 * <pre>
 * {
 *    "jsonrpc": "2.0",
 *    "method": "Foo.test",
 *    "params": ["some", "thing"],
 *    "id": 1
 * }
 * </pre>
 */
public class JsonRpcMultiServer extends JsonRpcServer {

    public static final char DEFAULT_SEPARATOR = '.';
    private static final Logger LOGGER = Logger.getLogger(JsonRpcMultiServer.class.getName());

    private Map<String, Object> handlerMap;
    private Map<String, Class<?>> interfaceMap;
    private char separator = DEFAULT_SEPARATOR;

    public JsonRpcMultiServer() {
        this(new ObjectMapper());
    }

    public JsonRpcMultiServer(ObjectMapper mapper) {
        super(mapper, (Object) null);
        this.handlerMap = new HashMap<String, Object>();
        this.interfaceMap = new HashMap<String, Class<?>>();
    }

    public JsonRpcMultiServer addService(String name, Object handler) {
        return addService(name, handler, null);
    }

    public JsonRpcMultiServer addService(String name, Object handler, Class<?> remoteInterface) {
        handlerMap.put(name, handler);
        if (remoteInterface != null) {
            interfaceMap.put(name, remoteInterface);
        }
        return this;
    }

    public char getSeparator() {
        return this.separator;
    }

    public void setSeparator(char separator) {
        this.separator = separator;
    }

    /**
     * Returns the handler's class or interfaces.  The serviceName is used
     * to look up a registered handler.
     *
     * @param serviceName the optional name of a service
     * @return the class
     */
    @Override
    protected Class<?>[] getHandlerInterfaces(String serviceName) {
        Class<?> remoteInterface = interfaceMap.get(serviceName);
        if (remoteInterface != null) {
            return new Class<?>[] { remoteInterface };
        } else if (Proxy.isProxyClass(getHandler(serviceName).getClass())) {
            return getHandler(serviceName).getClass().getInterfaces();
        } else {
            return new Class<?>[] { getHandler(serviceName).getClass() };
        }
    }

    /**
     * Get the handler (object) that should be invoked to execute the specified
     * RPC method based on the specified service name.
     *
     * @param serviceName the service name
     * @return the handler to invoke the RPC call against
     */
    @Override
    protected Object getHandler(String serviceName) {
        Object handler = handlerMap.get(serviceName);
        if (handler == null) {
            LOGGER.log(Level.SEVERE, "Service '" + serviceName + "' is not registered in this multi-server");
            throw new RuntimeException("Service '" + serviceName + "' does not exist");
        }
        return handler;
    }

    /**
     * Get the service name from the methodNode.  JSON-RPC methods with the form
     * Service.method will result in "Service" being returned in this case.
     *
     * @param methodNode the JsonNode for the method
     * @return the name of the service, or <code>null</code>
     */
    @Override
    protected String getServiceName(JsonNode methodNode) {
        String methodName = (methodNode != null && !methodNode.isNull()) ? methodNode.asText() : null;
        if (methodName != null) {
            int ndx = methodName.indexOf(this.separator);
            if (ndx > 0) {
                return methodName.substring(0, ndx);
            }
        }
        return methodName;
    }

    /**
     * Get the method name from the methodNode, stripping off the service name.
     *
     * @param methodNode the JsonNode for the method
     * @return the name of the method that should be invoked
     */
    @Override
    protected String getMethodName(JsonNode methodNode) {
        String methodName = (methodNode != null && !methodNode.isNull()) ? methodNode.asText() : null;
        if (methodName != null) {
            int ndx = methodName.indexOf(this.separator);
            if (ndx > 0) {
                return methodName.substring(ndx + 1);
            }
        }
        return methodName;
    }
}