content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF 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 org.apache.ambari.server.view;
  
  import java.util.List;
  import java.util.Map;
  
  import org.apache.ambari.server.controller.spi.PropertyProvider;
  import org.apache.ambari.server.controller.spi.ProviderModule;
  import org.apache.ambari.server.controller.spi.Resource;
  import org.apache.ambari.server.controller.spi.ResourceProvider;
  
  /**
   * Module which allows for discovery of view resource providers.
   * This module wraps another module and delegates to it for
   * any resource types not defined in a view.
   */
  public class ViewProviderModule implements ProviderModule {
    /**
     * The delegate provider module.
     */
    private final ProviderModule providerModule;
  
  
    // ----- Constructors ------------------------------------------------------
  
    /**
     * Construct a view provider module.
     *
     * @param providerModule     the delegate provider module
     */
    private ViewProviderModule(ProviderModule providerModule) {
      this.providerModule = providerModule;
    }
  
  
    // ----- ProviderModule ----------------------------------------------------
  
    @Override
    public ResourceProvider getResourceProvider(Resource.Type type) {
  
      Map<Resource.Type, ResourceProvider> resourceProviders =
          ViewRegistry.getInstance().getResourceProviders();
  
      if (resourceProviders.containsKey(type)) {
        return resourceProviders.get(type);
      }
      return providerModule.getResourceProvider(type);
    }
  
    @Override
    public List<PropertyProvider> getPropertyProviders(Resource.Type type) {
      return providerModule.getPropertyProviders(type);
    }
  
  
    // ----- helper methods -----------------------------------------
  
    /**
     * Factory method to get a view provider module.
     *
     * @param module  the delegate provider module
     *
     * @return a view provider module
     */
    public static ViewProviderModule getViewProviderModule(ProviderModule module) {
      return new ViewProviderModule(module);
    }
  }
  