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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.
*/
package org.apache.calcite.rel.logical;
import com.google.common.collect.ImmutableList;
import org.apache.calcite.plan.Convention;
import org.apache.calcite.plan.RelOptCluster;
import org.apache.calcite.plan.RelOptTable;
import org.apache.calcite.plan.RelTraitSet;
import org.apache.calcite.rel.RelCollationTraitDef;
import org.apache.calcite.rel.RelInput;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.rel.RelWriter;
import org.apache.calcite.rel.core.TableScan;
import org.apache.calcite.rel.hint.RelHint;
import org.apache.calcite.schema.Table;
import java.util.List;
/**
* A LogicalTableScan reads all the rows from a {@link RelOptTable}.
*
* This class is copied from Calcite because the {@link #explainTerms} should consider hints.
*
*
If the table is a net.sf.saffron.ext.JdbcTable, then this is literally possible.
* But for other kinds of tables, there may be many ways to read the data from the table. For some
* kinds of table, it may not even be possible to read all of the rows unless some narrowing
* constraint is applied.
*
*
In the example of the net.sf.saffron.ext.ReflectSchema schema,
*
*
*
* select from fields
*
*
*
* cannot be implemented, but
*
*
*
* select from fields as f
* where f.getClass().getName().equals("java.lang.String")
*
*
*
* can. It is the optimizer's responsibility to find these ways, by applying transformation
* rules.
*/
public final class LogicalTableScan extends TableScan {
// ~ Constructors -----------------------------------------------------------
/**
* Creates a LogicalTableScan.
*
*
Use {@link #create} unless you know what you're doing.
*/
public LogicalTableScan(
RelOptCluster cluster, RelTraitSet traitSet, List hints, RelOptTable table) {
super(cluster, traitSet, hints, table);
}
@Deprecated // to be removed before 2.0
public LogicalTableScan(RelOptCluster cluster, RelTraitSet traitSet, RelOptTable table) {
this(cluster, traitSet, ImmutableList.of(), table);
}
@Deprecated // to be removed before 2.0
public LogicalTableScan(RelOptCluster cluster, RelOptTable table) {
this(cluster, cluster.traitSetOf(Convention.NONE), ImmutableList.of(), table);
}
/** Creates a LogicalTableScan by parsing serialized output. */
public LogicalTableScan(RelInput input) {
super(input);
}
@Override
public RelNode copy(RelTraitSet traitSet, List inputs) {
assert traitSet.containsIfApplicable(Convention.NONE);
assert inputs.isEmpty();
return this;
}
// BEGIN FLINK MODIFICATION
// {@link #explainTerms} method should consider hints due to CALCITE-4581.
// This file should be remove once CALCITE-4581 is fixed.
@Override
public RelWriter explainTerms(RelWriter pw) {
return super.explainTerms(pw).itemIf("hints", getHints(), !getHints().isEmpty());
}
// END FLINK MODIFICATION
/**
* Creates a LogicalTableScan.
*
* @param cluster Cluster
* @param relOptTable Table
* @param hints The hints
*/
public static LogicalTableScan create(
RelOptCluster cluster, final RelOptTable relOptTable, List hints) {
final Table table = relOptTable.unwrap(Table.class);
final RelTraitSet traitSet =
cluster.traitSetOf(Convention.NONE)
.replaceIfs(
RelCollationTraitDef.INSTANCE,
() -> {
if (table != null) {
return table.getStatistic().getCollations();
}
return ImmutableList.of();
});
return new LogicalTableScan(cluster, traitSet, hints, relOptTable);
}
@Override
public RelNode withHints(List hintList) {
return new LogicalTableScan(getCluster(), traitSet, hintList, table);
}
}