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.optimizer.rules;
  
  import java.util.List;
  
  import org.apache.commons.lang3.mutable.Mutable;
  import org.apache.hyracks.algebricks.common.exceptions.AlgebricksException;
  import org.apache.hyracks.algebricks.core.algebra.base.ILogicalExpression;
  import org.apache.hyracks.algebricks.core.algebra.base.ILogicalOperator;
  import org.apache.hyracks.algebricks.core.algebra.base.IOptimizationContext;
  import org.apache.hyracks.algebricks.core.algebra.base.LogicalExpressionTag;
  import org.apache.hyracks.algebricks.core.algebra.base.LogicalOperatorTag;
  import org.apache.hyracks.algebricks.core.algebra.operators.logical.WriteOperator;
  import org.apache.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule;
  
  public class CleanupWriteOperatorRule implements IAlgebraicRewriteRule {
      @Override
      public boolean rewritePre(Mutable<ILogicalOperator> opRef, IOptimizationContext context)
              throws AlgebricksException {
          ILogicalOperator op = opRef.getValue();
          if (op.getOperatorTag() != LogicalOperatorTag.WRITE) {
              return false;
          }
  
          WriteOperator writeOp = (WriteOperator) op;
          ILogicalExpression pathExpr = writeOp.getPathExpression().getValue();
          if (pathExpr.getExpressionTag() != LogicalExpressionTag.CONSTANT) {
              return false;
          }
  
          boolean changed = false;
          List<Mutable<ILogicalExpression>> partitionExprs = writeOp.getPartitionExpressions();
          if (!partitionExprs.isEmpty()) {
              // Useless partition expressions due to having a constant path expression
              partitionExprs.clear();
              writeOp.getOrderExpressions().clear();
              changed = true;
          }
  
          return changed;
      }
  }
  