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 org.apache.asterix.metadata.declared.DataSource;
  import org.apache.asterix.optimizer.base.AsterixOptimizationContext;
  import org.apache.commons.lang3.mutable.Mutable;
  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.LogicalOperatorTag;
  import org.apache.hyracks.algebricks.core.algebra.operators.logical.DataSourceScanOperator;
  import org.apache.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule;
  
  /**
   * Finds data sources used by {@link LogicalOperatorTag#DATASOURCESCAN DATASOURCESCAN} operators and
   * adds them to the optimization context to be used later by {@link SetAsterixMemoryRequirementsRule}
   */
  public final class FindDataSourcesRule implements IAlgebraicRewriteRule {
      @Override
      public boolean rewritePre(Mutable<ILogicalOperator> opRef, IOptimizationContext context) {
          ILogicalOperator op = opRef.getValue();
          if (op.getOperatorTag() == LogicalOperatorTag.DATASOURCESCAN) {
              DataSourceScanOperator scanOp = (DataSourceScanOperator) op;
              DataSource dataSource = (DataSource) scanOp.getDataSource();
              AsterixOptimizationContext ctx = (AsterixOptimizationContext) context;
              ctx.addDataSource(dataSource);
          }
          return false;
      }
  
      @Override
      public boolean rewritePost(Mutable<ILogicalOperator> opRef, IOptimizationContext context) {
          return false;
      }
  }
  