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.stack.upgrade;
  
  import java.util.EnumSet;
  
  import javax.xml.bind.annotation.XmlAttribute;
  import javax.xml.bind.annotation.XmlElement;
  import javax.xml.bind.annotation.XmlSeeAlso;
  
  import org.apache.ambari.server.stack.upgrade.orchestrate.StageWrapper;
  
  import com.google.gson.Gson;
  import com.google.gson.GsonBuilder;
  import com.google.gson.annotations.Expose;
  
  
  /**
   * Base class to identify the items that could possibly occur during an upgrade
   */
  @XmlSeeAlso(
      value = { ExecuteTask.class, CreateAndConfigureTask.class, ConfigureTask.class,
          ManualTask.class, RestartTask.class, StartTask.class, StopTask.class,
          ServerActionTask.class, ConfigureFunction.class, AddComponentTask.class,
          RegenerateKeytabsTask.class })
  public abstract class Task {
  
    /**
     * A Gson instance to use when doing simple serialization along with
     * {@link Expose}.
     */
    protected final static Gson GSON = new GsonBuilder()
        .serializeNulls()
        .setPrettyPrinting()
        .excludeFieldsWithoutExposeAnnotation()
        .create();
  
    /**
     * An optional brief description of what this task is doing.
     */
    @Expose
    @XmlElement(name = "summary")
    public String summary;
  
    /**
     * Whether the task needs to run sequentially, i.e., on its own stage.
     * If false, will be grouped with other tasks.
     */
    @Expose
    @XmlAttribute(name = "sequential")
    public boolean isSequential = false;
  
    /**
     * The config property to check for timeout.
     */
    @Expose
    @XmlAttribute(name="timeout-config")
    public String timeoutConfig = null;
  
    /**
     * A condition element with can prevent this task from being scheduled in the
     * upgrade.
     */
    @XmlElement(name = "condition")
    public Condition condition;
  
    /**
     * @return the type of the task
     */
    public abstract Type getType();
  
    /**
     * @return when a single Task is constructed, this is the type of stage it should belong to.
     */
    public abstract StageWrapper.Type getStageWrapperType();
  
    /**
     * @return a verb to display that describes the type of task, e.g., "executing".
     */
    public abstract String getActionVerb();
  
    /**
     * The scope for the task
     */
    @Expose
    @XmlElement(name = "scope")
    public UpgradeScope scope = UpgradeScope.ANY;
  
  
    @Override
    public String toString() {
      return getType().toString();
    }
  
    /**
     * Gets the summary of the task or {@code null}.
     *
     * @return the task summary or {@code null}.
     */
    public String getSummary() {
      return summary;
    }
  
    /**
     * Identifies the type of task.
     */
    public enum Type {
      /**
       * Task that is executed on a host.
       */
      EXECUTE,
      /**
       * Task that alters a configuration.
       */
      CONFIGURE,
      /**
       * Task that create a config type if it does not, and alters a configuration.
       */
      CREATE_AND_CONFIGURE,
      /**
       * Task that sets up the configuration for subsequent task
       */
      CONFIGURE_FUNCTION,
      /**
       * Task that displays a message and must be confirmed before continuing
       */
      MANUAL,
      /**
       * Task that is a restart command.
       */
      RESTART,
      /**
       * Task that is a start command.
       */
      START,
      /**
       * Task that is a stop command.
       */
      STOP,
      /**
       * Task that is a service check
       */
      SERVICE_CHECK,
      /**
       * Task meant to run against Ambari server.
       */
      SERVER_ACTION,
  
      /**
       * A task which adds new components to the cluster during the upgrade.
       */
      ADD_COMPONENT,
  
      /**
       * Create keytab regeneration steps as part of the upgrade.
       */
      REGENERATE_KEYTABS;
  
      /**
       * Commands which run on the server.
       */
      public static final EnumSet<Type> SERVER_ACTIONS = EnumSet.of(MANUAL, CONFIGURE, SERVER_ACTION,
          ADD_COMPONENT);
  
      /**
       * Commands which are run on agents.
       */
      public static final EnumSet<Type> COMMANDS = EnumSet.of(RESTART, START, CONFIGURE_FUNCTION,
          STOP, SERVICE_CHECK, REGENERATE_KEYTABS);
  
      /**
       * @return {@code true} if the task is manual or automated.
       */
      public boolean isServerAction() {
        return SERVER_ACTIONS.contains(this);
      }
  
      /**
       * @return {@code true} if the task is a command type (as opposed to an action)
       */
      public boolean isCommand() {
        return COMMANDS.contains(this);
      }
    }
  }
  