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.typecomputer.impl;
  
  import org.apache.asterix.om.exceptions.TypeMismatchException;
  import org.apache.asterix.om.typecomputer.base.IResultTypeComputer;
  import org.apache.asterix.om.types.ATypeTag;
  import org.apache.asterix.om.types.AUnionType;
  import org.apache.asterix.om.types.AbstractCollectionType;
  import org.apache.asterix.om.types.BuiltinType;
  import org.apache.asterix.om.types.IAType;
  import org.apache.hyracks.algebricks.common.exceptions.AlgebricksException;
  import org.apache.hyracks.algebricks.core.algebra.base.ILogicalExpression;
  import org.apache.hyracks.algebricks.core.algebra.expressions.AbstractFunctionCallExpression;
  import org.apache.hyracks.algebricks.core.algebra.expressions.IVariableTypeEnvironment;
  import org.apache.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
  import org.apache.hyracks.algebricks.core.algebra.metadata.IMetadataProvider;
  
  public class SubsetCollectionTypeComputer implements IResultTypeComputer {
  
      public static final SubsetCollectionTypeComputer INSTANCE = new SubsetCollectionTypeComputer();
  
      private SubsetCollectionTypeComputer() {
      }
  
      @Override
      public IAType computeType(ILogicalExpression expression, IVariableTypeEnvironment env, IMetadataProvider<?, ?> mp)
              throws AlgebricksException {
          AbstractFunctionCallExpression fun = (AbstractFunctionCallExpression) expression;
          FunctionIdentifier funcId = fun.getFunctionIdentifier();
  
          IAType t = (IAType) env.getType(fun.getArguments().get(0).getValue());
          ATypeTag actualTypeTag = t.getTypeTag();
          switch (actualTypeTag) {
              case MULTISET:
              case ARRAY: {
                  AbstractCollectionType act = (AbstractCollectionType) t;
                  return act.getItemType();
              }
              case UNION: {
                  AUnionType ut = (AUnionType) t;
                  if (!ut.isUnknownableType()) {
                      throw new TypeMismatchException(fun.getSourceLocation(), funcId, 0, actualTypeTag,
                              ATypeTag.MULTISET, ATypeTag.ARRAY);
                  }
                  IAType t2 = ut.getActualType();
                  ATypeTag tag2 = t2.getTypeTag();
                  if (tag2 == ATypeTag.MULTISET || tag2 == ATypeTag.ARRAY) {
                      AbstractCollectionType act = (AbstractCollectionType) t2;
                      return act.getItemType();
                  }
                  throw new TypeMismatchException(fun.getSourceLocation(), funcId, 0, actualTypeTag, ATypeTag.MULTISET,
                          ATypeTag.ARRAY);
              }
              case ANY:
                  return BuiltinType.ANY;
              default:
                  throw new TypeMismatchException(fun.getSourceLocation(), funcId, 0, actualTypeTag, ATypeTag.MULTISET,
                          ATypeTag.ARRAY);
          }
      }
  }
  