JsonClient.java

/**
 * Copyright 2010 CosmoCode GmbH
 *
 * Licensed 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 de.cosmocode.palava.ipc.json;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.util.List;
import java.util.Map;

import org.codehaus.jackson.map.ObjectMapper;

import de.cosmocode.palava.ipc.netty.AbstractClient;
import de.cosmocode.palava.ipc.netty.Client;
import de.cosmocode.palava.ipc.netty.ClientConnection;
import de.cosmocode.palava.ipc.netty.NettyClient;

/**
 * Json specific {@link Client} implementation.
 *
 * @since 1.0
 * @author Willi Schoenborn
 */
public final class JsonClient extends AbstractClient {

    private final ObjectMapper mapper = new ObjectMapper();
    
    private final Client client = new NettyClient();
    
    @Override
    public JsonClientConnection connect(InetSocketAddress address) {
        final ClientConnection connection = client.connect(address);
        return new InternalJsonConnection(connection);
    }
    
    /**
     * Internal implementation of the {@link JsonClientConnection} interface.
     *
     * @since 1.0
     * @author Willi Schoenborn
     */
    private final class InternalJsonConnection implements JsonClientConnection {
        
        private final ClientConnection connection;
        
        public InternalJsonConnection(ClientConnection connection) {
            this.connection = connection;
        }

        @Override
        public String send(String request) {
            return connection.send(request);
        }
        
        @Override
        public void disconnect() {
            connection.disconnect();
        }
        
        @Override
        public <T> T send(Map<?, ?> request) {
            return this.<T>send(Object.class.cast(request));
        }
        
        @Override
        public <T> T send(List<?> request) {
            return this.<T>send(Object.class.cast(request));
        }
        
        private <T> T send(Object request) {
            try {
                @SuppressWarnings("unchecked")
                final T result = (T) read(send(mapper.writeValueAsString(request)));
                return result;
            } catch (IOException e) {
                throw new IllegalArgumentException(e);
            }
        }
        
        private Object read(String value) throws IOException {
            if (value.charAt(0) == '[') {
                return mapper.readValue(value, List.class);
            } else if (value.charAt(0) == '{') {
                return mapper.readValue(value, Map.class);
            } else {
                throw new IllegalArgumentException(String.format("%s is no valid json", value));
            }
        }
        
    }

    @Override
    public void shutdown() {
        client.shutdown();
    }

}