com.hazelcast.org.apache.calcite.rel.rules.ProjectRemoveRule 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 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.
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package com.hazelcast.org.apache.calcite.rel.rules;
import com.hazelcast.org.apache.calcite.plan.RelOptRuleCall;
import com.hazelcast.org.apache.calcite.plan.RelRule;
import com.hazelcast.org.apache.calcite.rel.RelNode;
import com.hazelcast.org.apache.calcite.rel.core.Project;
import com.hazelcast.org.apache.calcite.rex.RexUtil;
import com.hazelcast.org.apache.calcite.tools.RelBuilderFactory;
import org.immutables.value.Value;
/**
* Planner rule that,
* given a {@link com.hazelcast.org.apache.calcite.rel.core.Project} node that
* merely returns its input, converts the node into its child.
*
* For example, Project(ArrayReader(a), {$input0})
becomes
* ArrayReader(a)
.
*
* @see CalcRemoveRule
* @see ProjectMergeRule
* @see CoreRules#PROJECT_REMOVE
*/
@Value.Enclosing
public class ProjectRemoveRule
extends RelRule
implements SubstitutionRule {
/** Creates a ProjectRemoveRule. */
protected ProjectRemoveRule(Config config) {
super(config);
}
@Deprecated // to be removed before 2.0
public ProjectRemoveRule(RelBuilderFactory relBuilderFactory) {
this(Config.DEFAULT.withRelBuilderFactory(relBuilderFactory)
.as(Config.class));
}
//~ Methods ----------------------------------------------------------------
@Override public void onMatch(RelOptRuleCall call) {
Project project = call.rel(0);
assert isTrivial(project);
RelNode stripped = project.getInput();
if (stripped instanceof Project) {
// Rename columns of child projection if desired field names are given.
Project childProject = (Project) stripped;
stripped = childProject.copy(childProject.getTraitSet(),
childProject.getInput(), childProject.getProjects(),
project.getRowType());
}
stripped = convert(stripped, project.getConvention());
call.transformTo(stripped);
}
/**
* Returns the child of a project if the project is trivial, otherwise
* the project itself.
*/
public static RelNode strip(Project project) {
return isTrivial(project) ? project.getInput() : project;
}
public static boolean isTrivial(Project project) {
return RexUtil.isIdentity(project.getProjects(),
project.getInput().getRowType());
}
@Override public boolean autoPruneOld() {
return true;
}
/** Rule configuration. */
@Value.Immutable
public interface Config extends RelRule.Config {
Config DEFAULT = ImmutableProjectRemoveRule.Config.of()
.withOperandSupplier(b ->
b.operand(Project.class)
// Use a predicate to detect non-matches early.
// This keeps the rule queue short.
.predicate(ProjectRemoveRule::isTrivial)
.anyInputs());
@Override default ProjectRemoveRule toRule() {
return new ProjectRemoveRule(this);
}
}
}
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