fe/src/main/java/org/apache/impala/analysis/UnionStmt.java

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//   http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.impala.analysis;

import java.util.List;
import org.apache.impala.common.AnalysisException;

/**
 * Representation of a union.
 */
public class UnionStmt extends SetOperationStmt {
  /////////////////////////////////////////
  // BEGIN: Members that need to be reset()


  // END: Members that need to be reset()
  /////////////////////////////////////////

  public UnionStmt(List<SetOperand> operands,
      List<OrderByElement> orderByElements, LimitElement limitElement) {
    super(operands, orderByElements, limitElement);
  }

  /**
   * C'tor for cloning.
   */
  protected UnionStmt(SetOperationStmt other) {
    super(other);
  }

  @Override
  public void analyze(Analyzer analyzer) throws AnalysisException {
    if (isAnalyzed()) return;
    super.analyze(analyzer);
  }

  @Override
  public SetOperationStmt clone() {
    return new UnionStmt(this);
  }

  /**
   * Undoes all changes made by analyze() except distinct propagation and unnesting.
   * After analysis, operands_ contains the list of unnested operands with qualifiers
   * adjusted to reflect distinct propagation. Every operand in that list is reset().
   * The unionDistinctOperands_ and unionAllOperands_ are cleared because they are
   * redundant
   * with operands_.
   */
  @Override
  public void reset() {
    super.reset();
    for (SetOperand op : operands_) op.reset();
    unionDistinctOperands_.clear();
    unionAllOperands_.clear();
    distinctAggInfo_ = null;
    tupleId_ = null;
    toSqlString_ = null;
    widestExprs_ = null;
  }
}