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.om.types;
  
  import org.apache.asterix.om.typecomputer.impl.TypeComputeUtils;
  import org.apache.hyracks.algebricks.common.exceptions.NotImplementedException;
  
  public class TypeHelper {
  
      private TypeHelper() {
      }
  
      public static boolean canBeMissing(IAType t) {
          switch (t.getTypeTag()) {
              case MISSING:
              case ANY:
                  return true;
              case UNION:
                  return ((AUnionType) t).isMissableType();
              default:
                  return false;
          }
      }
  
      public static boolean canBeNull(IAType t) {
          switch (t.getTypeTag()) {
              case NULL:
              case ANY:
                  return true;
              case UNION:
                  return ((AUnionType) t).isNullableType();
              default:
                  return false;
          }
      }
  
      public static boolean canBeUnknown(IAType t) {
          switch (t.getTypeTag()) {
              case MISSING:
              case NULL:
              case ANY:
                  return true;
              case UNION:
                  return ((AUnionType) t).isUnknownableType();
              default:
                  return false;
          }
      }
  
      public static boolean isClosed(IAType t) {
          switch (t.getTypeTag()) {
              case MISSING:
              case ANY:
                  return false;
              case UNION:
                  return isClosed(((AUnionType) t).getActualType());
              default:
                  return true;
          }
      }
  
      /**
       * Decides whether the {@param type} represents a type for data in the "opened up" form.
       * @param type type
       * @return true if the type will represent data in the "opened up" form. False, otherwise.
       */
      public static boolean isFullyOpen(IAType type) {
          IAType actualType = TypeComputeUtils.getActualType(type);
          switch (actualType.getTypeTag()) {
              case OBJECT:
                  ARecordType recordType = (ARecordType) actualType;
                  return recordType.getFieldNames().length == 0 && recordType.isOpen();
              case ARRAY:
              case MULTISET:
                  AbstractCollectionType collectionType = (AbstractCollectionType) actualType;
                  return TypeComputeUtils.getActualType(collectionType.getItemType()).getTypeTag() == ATypeTag.ANY;
              case ANY:
                  return true;
              default:
                  if (actualType.getTypeTag().isDerivedType()) {
                      throw new NotImplementedException();
                  }
                  // all other scalar types & ANY are open by nature and they don't need to be "opened up"
                  return true;
          }
      }
  }
  