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.asterix.metadata.dataset.hints;
  
  import java.util.HashSet;
  import java.util.Set;
  
  import org.apache.asterix.common.dataflow.ICcApplicationContext;
  import org.apache.hyracks.algebricks.common.utils.Pair;
  
  /**
   * Collection of hints supported by create dataset statement.
   * Includes method to validate a hint and its associated value
   * as provided in a create dataset statement.
   */
  public class DatasetHints {
  
      private DatasetHints() {
      }
  
      /**
       * validate the use of a hint
       *
       * @param hintName
       *            name of the hint
       * @param value
       *            value associated with the hint
       * @return a Pair with
       *         first element as a boolean that represents the validation result.
       *         second element as the error message if the validation result is false
       */
      public static Pair<Boolean, String> validate(ICcApplicationContext appCtx, String hintName, String value) {
          for (IHint h : hints) {
              if (h.getName().equalsIgnoreCase(hintName.trim())) {
                  return h.validateValue(appCtx, value);
              }
          }
          return new Pair<>(false, "Unknown hint :" + hintName);
      }
  
      private static Set<IHint> hints = initHints();
  
      private static Set<IHint> initHints() {
          Set<IHint> hints = new HashSet<>();
          hints.add(new DatasetCardinalityHint());
          hints.add(new DatasetNodegroupCardinalityHint());
          return hints;
      }
  
      /**
       * Hint representing the expected number of tuples in the dataset.
       */
      public static class DatasetCardinalityHint implements IHint {
          public static final String NAME = "CARDINALITY";
  
          public static final long DEFAULT = 1000000L;
  
          @Override
          public String getName() {
              return NAME;
          }
  
          @Override
          public Pair<Boolean, String> validateValue(ICcApplicationContext appCtx, String value) {
              boolean valid = true;
              long longValue;
              try {
                  longValue = Long.parseLong(value);
                  if (longValue < 0) {
                      return new Pair<>(false, "Value must be >= 0");
                  }
              } catch (NumberFormatException nfe) {
                  valid = false;
                  return new Pair<>(valid, "Inappropriate value");
              }
              return new Pair<>(true, null);
          }
  
      }
  
      /**
       * Hint representing the cardinality of nodes forming the nodegroup for the dataset.
       */
      public static class DatasetNodegroupCardinalityHint implements IHint {
          public static final String NAME = "NODEGROUP_CARDINALITY";
  
          public static final int DEFAULT = 1;
  
          @Override
          public String getName() {
              return NAME;
          }
  
          @Override
          public Pair<Boolean, String> validateValue(ICcApplicationContext appCtx, String value) {
              int intValue;
              try {
                  intValue = Integer.parseInt(value);
                  if (intValue < 0) {
                      return new Pair<>(false, "Value must be >= 0");
                  }
                  int numNodesInCluster = appCtx.getClusterStateManager().getParticipantNodes(true).size();
                  if (numNodesInCluster < intValue) {
                      return new Pair<>(false,
                              "Value must be less than or equal to the available number of nodes in cluster ("
                                      + numNodesInCluster + ")");
                  }
              } catch (NumberFormatException nfe) {
                  return new Pair<>(false, "Inappropriate value");
              }
              return new Pair<>(true, null);
          }
  
      }
  
  }
  