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 io.activej.dataflow.calcite.optimizer;
  
  import io.activej.dataflow.calcite.rel.DataflowTableScan;
  import org.apache.calcite.plan.RelOptRule;
  import org.apache.calcite.plan.RelOptRuleCall;
  import org.apache.calcite.plan.RelRule;
  import org.apache.calcite.rel.logical.LogicalFilter;
  import org.apache.calcite.rex.RexNode;
  
  public class FilterScanTableRule extends RelRule<FilterScanTableRule.Config> {
  
  	private FilterScanTableRule(FilterScanTableRule.Config config) {
  		super(config);
  	}
  
  	public static FilterScanTableRule create() {
  		return new FilterScanTableRule(Config.INSTANCE);
  	}
  
  	@Override
  	public void onMatch(RelOptRuleCall call) {
  		LogicalFilter filter = call.rel(0);
  		DataflowTableScan scan = call.rel(1);
  
  		if (scan.getCondition() != null) return;
  
  		RexNode condition = filter.getCondition();
  		if (condition.isAlwaysTrue()) return;
  
  		scan.setCondition(condition);
  
  		call.transformTo(scan);
  	}
  
  	public static final class Config extends LimitedConfig {
  		private static final Config INSTANCE = new Config();
  
  		@Override
  		public RelOptRule toRule() {
  			return new FilterScanTableRule(this);
  		}
  
  		@Override
  		public OperandTransform operandSupplier() {
  			return b -> b.operand(LogicalFilter.class)
  				.oneInput(b1 -> b1.operand(DataflowTableScan.class).noInputs());
  		}
  	}
  }
  