core/src/main/java/org/apache/carbondata/core/scan/filter/resolver/resolverinfo/visitor/ImplicitColumnVisitor.java

/*
 * 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.carbondata.core.scan.filter.resolver.resolverinfo.visitor;

import java.util.Map;
import java.util.Set;

import org.apache.carbondata.core.scan.expression.conditional.ImplicitExpression;
import org.apache.carbondata.core.scan.expression.exception.FilterUnsupportedException;
import org.apache.carbondata.core.scan.filter.ColumnFilterInfo;
import org.apache.carbondata.core.scan.filter.FilterUtil;
import org.apache.carbondata.core.scan.filter.resolver.metadata.FilterResolverMetadata;
import org.apache.carbondata.core.scan.filter.resolver.resolverinfo.ColumnResolvedFilterInfo;
import org.apache.carbondata.core.scan.filter.resolver.resolverinfo.DimColumnResolvedFilterInfo;

public class ImplicitColumnVisitor implements ResolvedFilterInfoVisitorIntf {

  /**
   * Visitor Method will update the filter related details in visitableObj, For implicit
   * type columns the filter members will resolved directly, no need to look up in dictionary
   * since it will not be part of dictionary, directly the actual data can be taken
   * and can be set. This type of encoding is effective when the particular column
   * is having very high cardinality.
   *
   * @param visitableObj
   * @param metadata
   * @throws FilterUnsupportedException,if exception occurs while evaluating
   *                                       filter models.
   */

  @Override
  public void populateFilterResolvedInfo(ColumnResolvedFilterInfo visitableObj,
      FilterResolverMetadata metadata) throws FilterUnsupportedException {
    if (visitableObj instanceof DimColumnResolvedFilterInfo) {
      ColumnFilterInfo resolvedFilterObject = null;
      if (metadata.getExpression() instanceof ImplicitExpression) {
        Map<String, Set<Integer>> blockIdToBlockletIdMapping =
            ((ImplicitExpression) metadata.getExpression()).getBlockIdToBlockletIdMapping();
        resolvedFilterObject = FilterUtil
            .getImplicitColumnFilterList(blockIdToBlockletIdMapping, metadata.isIncludeFilter());
        ((DimColumnResolvedFilterInfo) visitableObj).setFilterValues(resolvedFilterObject);
      } else {
        throw new FilterUnsupportedException("Expression not an instance of implicit expression");
      }
    }
  }
}