Collect.java
/*
* 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.core;
import org.apache.calcite.plan.Convention;
import org.apache.calcite.plan.RelOptCluster;
import org.apache.calcite.plan.RelTraitSet;
import org.apache.calcite.rel.RelInput;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.rel.RelWriter;
import org.apache.calcite.rel.SingleRel;
import org.apache.calcite.rel.type.RelDataType;
import org.apache.calcite.rel.type.RelDataTypeFactory;
import org.apache.calcite.sql.SqlKind;
import org.apache.calcite.sql.type.SqlTypeName;
import org.apache.calcite.sql.type.SqlTypeUtil;
import com.google.common.collect.Iterables;
import java.util.List;
import static java.util.Objects.requireNonNull;
/**
* A relational expression that collapses multiple rows into one.
*
* <p>Rules:
*
* <ul>
* <li>{@link org.apache.calcite.rel.rules.SubQueryRemoveRule}
* creates a Collect from a call to
* {@link org.apache.calcite.sql.fun.SqlArrayQueryConstructor},
* {@link org.apache.calcite.sql.fun.SqlMapQueryConstructor}, or
* {@link org.apache.calcite.sql.fun.SqlMultisetQueryConstructor}.</li>
* </ul>
*/
public class Collect extends SingleRel {
//~ Instance fields --------------------------------------------------------
//~ Constructors -----------------------------------------------------------
/**
* Creates a Collect.
*
* <p>Use {@link #create} unless you know what you're doing.
*
* @param cluster Cluster
* @param traitSet Trait set
* @param input Input relational expression
* @param rowType Row type
*/
protected Collect(
RelOptCluster cluster,
RelTraitSet traitSet,
RelNode input,
RelDataType rowType) {
super(cluster, traitSet, input);
this.rowType = requireNonNull(rowType, "rowType");
final SqlTypeName collectionType = getCollectionType(rowType);
switch (collectionType) {
case ARRAY:
case MAP:
case MULTISET:
break;
default:
throw new IllegalArgumentException("not a collection type "
+ collectionType);
}
}
@Deprecated // to be removed before 2.0
public Collect(
RelOptCluster cluster,
RelTraitSet traitSet,
RelNode input,
String fieldName) {
this(cluster, traitSet, input,
deriveRowType(cluster.getTypeFactory(), SqlTypeName.MULTISET, fieldName,
input.getRowType()));
}
/**
* Creates a Collect by parsing serialized output.
*/
public Collect(RelInput input) {
this(input.getCluster(), input.getTraitSet(), input.getInput(),
deriveRowType(input.getCluster().getTypeFactory(), SqlTypeName.MULTISET,
requireNonNull(input.getString("field"), "field"),
input.getInput().getRowType()));
}
//~ Methods ----------------------------------------------------------------
/**
* Creates a Collect.
*
* @param input Input relational expression
* @param rowType Row type
*/
public static Collect create(RelNode input, RelDataType rowType) {
final RelOptCluster cluster = input.getCluster();
final RelTraitSet traitSet =
cluster.traitSet().replace(Convention.NONE);
return new Collect(cluster, traitSet, input, rowType);
}
/**
* Creates a Collect.
*
* @param input Input relational expression
* @param collectionType ARRAY, MAP or MULTISET
* @param fieldName Name of the sole output field
*/
@Deprecated // to be removed before 2.0
public static Collect create(RelNode input,
SqlTypeName collectionType,
String fieldName) {
return create(input,
deriveRowType(input.getCluster().getTypeFactory(), collectionType,
fieldName, input.getRowType()));
}
/**
* Creates a Collect.
*
* @param input Input relational expression
* @param sqlKind SqlKind
* @param fieldName Name of the sole output field
*/
public static Collect create(RelNode input,
SqlKind sqlKind,
String fieldName) {
SqlTypeName collectionType = getCollectionType(sqlKind);
RelDataType rowType;
switch (sqlKind) {
case ARRAY_QUERY_CONSTRUCTOR:
case MAP_QUERY_CONSTRUCTOR:
case MULTISET_QUERY_CONSTRUCTOR:
rowType =
deriveRowType(input.getCluster().getTypeFactory(), collectionType,
fieldName,
SqlTypeUtil.deriveCollectionQueryComponentType(collectionType,
input.getRowType()));
break;
default:
rowType =
deriveRowType(input.getCluster().getTypeFactory(), collectionType,
fieldName, input.getRowType());
}
return create(input, rowType);
}
/** Returns the row type, guaranteed not null.
* (The row type is never null after initialization, but
* CheckerFramework can't deduce that references are safe.) */
protected final RelDataType rowType() {
return requireNonNull(rowType, "rowType");
}
@Override public final RelNode copy(RelTraitSet traitSet,
List<RelNode> inputs) {
return copy(traitSet, sole(inputs));
}
public RelNode copy(RelTraitSet traitSet, RelNode input) {
assert traitSet.containsIfApplicable(Convention.NONE);
return new Collect(getCluster(), traitSet, input, rowType());
}
@Override public RelWriter explainTerms(RelWriter pw) {
return super.explainTerms(pw)
.item("field", getFieldName());
}
/**
* Returns the name of the sole output field.
*
* @return name of the sole output field
*/
public String getFieldName() {
return Iterables.getOnlyElement(rowType().getFieldList()).getName();
}
/** Returns the collection type (ARRAY, MAP, or MULTISET). */
public SqlTypeName getCollectionType() {
return getCollectionType(rowType());
}
private static SqlTypeName getCollectionType(RelDataType rowType) {
return Iterables.getOnlyElement(rowType.getFieldList())
.getType().getSqlTypeName();
}
private static SqlTypeName getCollectionType(SqlKind sqlKind) {
switch (sqlKind) {
case ARRAY_QUERY_CONSTRUCTOR:
case ARRAY_VALUE_CONSTRUCTOR:
return SqlTypeName.ARRAY;
case MULTISET_QUERY_CONSTRUCTOR:
case MULTISET_VALUE_CONSTRUCTOR:
return SqlTypeName.MULTISET;
case MAP_QUERY_CONSTRUCTOR:
case MAP_VALUE_CONSTRUCTOR:
return SqlTypeName.MAP;
default:
throw new IllegalArgumentException("not a collection kind "
+ sqlKind);
}
}
@Override protected RelDataType deriveRowType() {
// this method should never be called; rowType is always set
throw new UnsupportedOperationException();
}
/**
* Derives the output row type of a Collect relational expression.
*
* @param rel relational expression
* @param fieldName name of sole output field
* @return output row type of a Collect relational expression
*/
@Deprecated // to be removed before 2.0
public static RelDataType deriveCollectRowType(
SingleRel rel,
String fieldName) {
RelDataType inputType = rel.getInput().getRowType();
assert inputType.isStruct();
return deriveRowType(rel.getCluster().getTypeFactory(),
SqlTypeName.MULTISET, fieldName, inputType);
}
/**
* Derives the output row type of a Collect relational expression.
*
* @param typeFactory Type factory
* @param collectionType MULTISET, ARRAY or MAP
* @param fieldName Name of sole output field
* @param elementType Element type
* @return output row type of a Collect relational expression
*/
public static RelDataType deriveRowType(RelDataTypeFactory typeFactory,
SqlTypeName collectionType, String fieldName, RelDataType elementType) {
final RelDataType type1;
switch (collectionType) {
case ARRAY:
type1 = SqlTypeUtil.createArrayType(typeFactory, elementType, false);
break;
case MULTISET:
type1 = SqlTypeUtil.createMultisetType(typeFactory, elementType, false);
break;
case MAP:
type1 = SqlTypeUtil.createMapTypeFromRecord(typeFactory, elementType);
break;
default:
throw new AssertionError(collectionType);
}
return typeFactory.createTypeWithNullability(
typeFactory.builder().add(fieldName, type1).build(), false);
}
}