labs/virtualbox/src/main/java/org/jclouds/virtualbox/functions/admin/ImagesToYamlImagesFromYamlDescriptor.java

/**
 * Licensed to jclouds, Inc. (jclouds) under one or more
 * contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  jclouds 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.jclouds.virtualbox.functions.admin;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;

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

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

import org.jclouds.compute.domain.Image;
import org.jclouds.virtualbox.domain.YamlImage;
import org.jclouds.virtualbox.functions.YamlImagesFromFileConfig;
import org.yaml.snakeyaml.Loader;
import org.yaml.snakeyaml.TypeDescription;
import org.yaml.snakeyaml.Yaml;
import org.yaml.snakeyaml.constructor.Constructor;

import com.google.common.base.Supplier;
import com.google.common.collect.Maps;

/**
 * @author Andrea Turli
 */
@Singleton
public class ImagesToYamlImagesFromYamlDescriptor implements Supplier<Map<Image, YamlImage>> {

   private String yamlDescriptor;

   @Inject
   public ImagesToYamlImagesFromYamlDescriptor(/*Supplier<String> yamlDescriptorSupplier*/YamlImagesFromFileConfig yamlDescriptorSupplier) {
      this.yamlDescriptor = yamlDescriptorSupplier.get();
      checkNotNull(yamlDescriptor, "yaml descriptor");
      checkState(!yamlDescriptor.equals(""), "yaml descriptor is empty");
   }

   /**
    * Type-safe config class for YAML
    * 
    */
   public static class Config {
      public List<YamlImage> images;
   }

   @Override
   public Map<Image, YamlImage> get() {

      Constructor constructor = new Constructor(Config.class);

      TypeDescription imageDesc = new TypeDescription(YamlImage.class);
      imageDesc.putListPropertyType("images", String.class);
      constructor.addTypeDescription(imageDesc);

      // Issue 855: testng is rev-locking us to snakeyaml 1.6
      // we have to use old constructor until this is fixed
      Yaml yaml = new Yaml(new Loader(constructor));
      Config config = (Config) yaml.load(yamlDescriptor);
      checkState(config != null, "missing config: class");
      checkState(config.images != null, "missing images: collection");

      Map<Image, YamlImage> backingMap = Maps.newLinkedHashMap();
      for (YamlImage yamlImage : config.images) {
         backingMap.put(YamlImage.toImage.apply(yamlImage), yamlImage);
      }
      return backingMap;
   }

}