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.utils.filter;
  
  import static org.apache.asterix.om.utils.ProjectionFiltrationTypeUtil.EMPTY_TYPE;
  import static org.apache.asterix.om.utils.ProjectionFiltrationTypeUtil.getMergedPathRecordType;
  import static org.apache.asterix.om.utils.ProjectionFiltrationTypeUtil.renameType;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.List;
  
  import org.apache.asterix.common.external.IExternalFilterEvaluatorFactory;
  import org.apache.asterix.external.input.filter.ExternalFilterEvaluatorFactory;
  import org.apache.asterix.external.input.filter.ExternalFilterValueEvaluatorFactory;
  import org.apache.asterix.external.input.filter.NoOpExternalFilterEvaluatorFactory;
  import org.apache.asterix.external.util.ExternalDataPrefix;
  import org.apache.asterix.om.types.ARecordType;
  import org.apache.asterix.om.types.BuiltinType;
  import org.apache.asterix.om.utils.ProjectionFiltrationTypeUtil;
  import org.apache.asterix.runtime.projection.ExternalDatasetProjectionFiltrationInfo;
  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.IVariableTypeEnvironment;
  import org.apache.hyracks.algebricks.core.jobgen.impl.JobGenContext;
  import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluatorFactory;
  
  public class ExternalFilterBuilder extends AbstractFilterBuilder {
      private final ExternalDataPrefix prefix;
      private final boolean embedFilterValues;
  
      public ExternalFilterBuilder(ExternalDatasetProjectionFiltrationInfo projectionFiltrationInfo,
              JobGenContext context, IVariableTypeEnvironment typeEnv, ExternalDataPrefix prefix) {
          super(projectionFiltrationInfo.getFilterPaths(), projectionFiltrationInfo.getFilterExpression(), context,
                  typeEnv);
          this.prefix = prefix;
          this.embedFilterValues = projectionFiltrationInfo.isEmbedFilterValues();
      }
  
      public IExternalFilterEvaluatorFactory build() throws AlgebricksException {
          IScalarEvaluatorFactory evalFactory = null;
          if (filterExpression != null && !filterPaths.isEmpty()) {
              evalFactory = createEvaluator(filterExpression);
          }
  
          if (evalFactory == null && !embedFilterValues) {
              return NoOpExternalFilterEvaluatorFactory.INSTANCE;
          }
  
          List<String> fieldPaths = prefix.getComputedFieldNames();
          int numberOfComputedFields = fieldPaths.size();
          List<ProjectionFiltrationTypeUtil.RenamedType> leafs = new ArrayList<>(numberOfComputedFields);
          ARecordType previousType = EMPTY_TYPE;
          for (int i = 0; i < numberOfComputedFields; i++) {
              ProjectionFiltrationTypeUtil.RenamedType renamedType = renameType(BuiltinType.ANY, i);
              leafs.add(renamedType);
              List<String> path = Arrays.asList(fieldPaths.get(i).split("\\."));
              previousType = getMergedPathRecordType(previousType, path, renamedType);
          }
  
          return new ExternalFilterEvaluatorFactory(evalFactory, previousType, leafs, prefix, embedFilterValues);
      }
  
      @Override
      protected IScalarEvaluatorFactory createValueAccessor(ILogicalExpression expression) {
          ARecordType path = filterPaths.get(expression);
          int index = prefix.getPaths().indexOf(path);
          return new ExternalFilterValueEvaluatorFactory(index, prefix.getComputedFieldTypes().get(index));
      }
  }
  