com.hazelcast.org.apache.calcite.rel.rules.ProjectCalcMergeRule Maven / Gradle / Ivy
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* 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 com.hazelcast.com.liance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.com.hazelcast.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 com.hazelcast.org.apache.calcite.rel.rules;
import com.hazelcast.org.apache.calcite.plan.RelOptCluster;
import com.hazelcast.org.apache.calcite.plan.RelOptRule;
import com.hazelcast.org.apache.calcite.plan.RelOptRuleCall;
import com.hazelcast.org.apache.calcite.rel.core.RelFactories;
import com.hazelcast.org.apache.calcite.rel.logical.LogicalCalc;
import com.hazelcast.org.apache.calcite.rel.logical.LogicalProject;
import com.hazelcast.org.apache.calcite.rex.RexBuilder;
import com.hazelcast.org.apache.calcite.rex.RexNode;
import com.hazelcast.org.apache.calcite.rex.RexOver;
import com.hazelcast.org.apache.calcite.rex.RexProgram;
import com.hazelcast.org.apache.calcite.rex.RexProgramBuilder;
import com.hazelcast.org.apache.calcite.tools.RelBuilderFactory;
import com.hazelcast.org.apache.calcite.util.Pair;
/**
* Planner rule which merges a
* {@link com.hazelcast.org.apache.calcite.rel.logical.LogicalProject} and a
* {@link com.hazelcast.org.apache.calcite.rel.logical.LogicalCalc}.
*
* The resulting {@link com.hazelcast.org.apache.calcite.rel.logical.LogicalCalc} has the
* same project list as the original
* {@link com.hazelcast.org.apache.calcite.rel.logical.LogicalProject}, but expressed in terms
* of the original {@link com.hazelcast.org.apache.calcite.rel.logical.LogicalCalc}'s inputs.
*
* @see FilterCalcMergeRule
*/
public class ProjectCalcMergeRule extends RelOptRule implements TransformationRule {
//~ Static fields/initializers ---------------------------------------------
public static final ProjectCalcMergeRule INSTANCE =
new ProjectCalcMergeRule(RelFactories.LOGICAL_BUILDER);
//~ Constructors -----------------------------------------------------------
/**
* Creates a ProjectCalcMergeRule.
*
* @param relBuilderFactory Builder for relational expressions
*/
public ProjectCalcMergeRule(RelBuilderFactory relBuilderFactory) {
super(
operand(
LogicalProject.class,
operand(LogicalCalc.class, any())),
relBuilderFactory, null);
}
//~ Methods ----------------------------------------------------------------
public void onMatch(RelOptRuleCall call) {
final LogicalProject project = call.rel(0);
final LogicalCalc calc = call.rel(1);
// Don't merge a project which contains windowed aggregates onto a
// calc. That would effectively be pushing a windowed aggregate down
// through a filter. Transform the project into an identical calc,
// which we'll have chance to merge later, after the over is
// expanded.
final RelOptCluster cluster = project.getCluster();
RexProgram program =
RexProgram.create(
calc.getRowType(),
project.getProjects(),
null,
project.getRowType(),
cluster.getRexBuilder());
if (RexOver.containsOver(program)) {
LogicalCalc projectAsCalc = LogicalCalc.create(calc, program);
call.transformTo(projectAsCalc);
return;
}
// Create a program containing the project node's expressions.
final RexBuilder rexBuilder = cluster.getRexBuilder();
final RexProgramBuilder progBuilder =
new RexProgramBuilder(
calc.getRowType(),
rexBuilder);
for (Pair field : project.getNamedProjects()) {
progBuilder.addProject(field.left, field.right);
}
RexProgram topProgram = progBuilder.getProgram();
RexProgram bottomProgram = calc.getProgram();
// Merge the programs together.
RexProgram mergedProgram =
RexProgramBuilder.mergePrograms(
topProgram,
bottomProgram,
rexBuilder);
final LogicalCalc newCalc =
LogicalCalc.create(calc.getInput(), mergedProgram);
call.transformTo(newCalc);
}
}