com.hazelcast.org.apache.calcite.rel.logical.LogicalTableScan 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.
*/
package com.hazelcast.org.apache.calcite.rel.logical;
import com.hazelcast.org.apache.calcite.plan.Convention;
import com.hazelcast.org.apache.calcite.plan.RelOptCluster;
import com.hazelcast.org.apache.calcite.plan.RelOptTable;
import com.hazelcast.org.apache.calcite.plan.RelTraitSet;
import com.hazelcast.org.apache.calcite.rel.RelCollationTraitDef;
import com.hazelcast.org.apache.calcite.rel.RelInput;
import com.hazelcast.org.apache.calcite.rel.RelNode;
import com.hazelcast.org.apache.calcite.rel.core.TableScan;
import com.hazelcast.org.apache.calcite.rel.hint.RelHint;
import com.hazelcast.org.apache.calcite.schema.Table;
import com.hazelcast.com.google.common.collect.ImmutableList;
import java.util.List;
/**
* A LogicalTableScan
reads all the rows from a
* {@link RelOptTable}.
*
* 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;
}
/** 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);
}
}