CommandFactory.java

/*
 * Copyright 2014-2016 CyberVision, Inc.
 *
 * 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 org.kaaproject.kaa.server.common.server;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * CommandFactory Class. Used as factory for Command processing classes
 *
 * @author Andrey Panasenko
 */
public class CommandFactory<U, V> {

  private static final Logger LOG = LoggerFactory.getLogger(CommandFactory.class);

  private final Map<String, KaaCommandProcessorFactory<U, V>> factories;

  /**
   * Create new instance of <code>CommandFactory</code>.
   *
   * @param factories is <code>List</code> of factories that adding to field <code>factories</code>
   *                  of new instance
   */
  public CommandFactory(List<KaaCommandProcessorFactory<U, V>> factories) {
    this.factories = new HashMap<>();
    for (KaaCommandProcessorFactory<U, V> factory : factories) {
      this.factories.put(factory.getCommandName(), factory);
    }
  }

  /**
   * getCommandProcessor - used to instantiate CommandProcessor for specific
   * URI.
   *
   * @param uri - HTTP request URI, should have following format: /DOMAIN/CommandName
   * @return - CommandProcessor
   * @throws Exception - throws if URI is incorrect or request command not found
   */
  //TODO: remove this method and move logic to http RequestDecoder
  public KaaCommandProcessor<U, V> getCommandProcessor(String uri) throws Exception { // NOSONAR
    if (uri == null || uri.length() <= 0) {
      throw new Exception("URI parameter incorrect"); // NOSONAR
    }
    String[] params = uri.split("/");
    if (params.length < 3) {
      throw new Exception("URI parameter " + uri + " incorrect"); // NOSONAR
    }
    // String domain = params[1];
    String command = params[2];
    LOG.trace("Command {} looking for URI {}", command, uri);
    KaaCommandProcessorFactory<U, V> factory = factories.get(command);
    if (factory != null) {
      LOG.trace("Command {} found", command);
      return factory.createCommandProcessor();
    } else {
      LOG.warn("Requested command not found: {}", command);
      throw new Exception("Requested command not found"); // NOSONAR
    }
  }
}