org.apache.calcite.rex.RexLocalRef 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 org.apache.calcite.rex;
import org.apache.calcite.rel.type.RelDataType;
import org.apache.calcite.sql.SqlKind;
import java.util.List;
import java.util.Objects;
/**
* Local variable.
*
* Identity is based upon type and index. We want multiple references to the
* same slot in the same context to be equal. A side effect is that references
* to slots in different contexts which happen to have the same index and type
* will be considered equal; this is not desired, but not too damaging, because
* of the immutability.
*
*
Variables are immutable.
*/
public class RexLocalRef extends RexSlot {
//~ Static fields/initializers ---------------------------------------------
// array of common names, to reduce memory allocations
@SuppressWarnings("MismatchedQueryAndUpdateOfCollection")
private static final List NAMES = new SelfPopulatingList("$t", 30);
//~ Constructors -----------------------------------------------------------
/**
* Creates a local variable.
*
* @param index Index of the field in the underlying row type
* @param type Type of the column
*/
public RexLocalRef(int index, RelDataType type) {
super(createName(index), index, type);
assert type != null;
assert index >= 0;
}
//~ Methods ----------------------------------------------------------------
@Override public SqlKind getKind() {
return SqlKind.LOCAL_REF;
}
public boolean equals(Object obj) {
return this == obj
|| obj instanceof RexLocalRef
&& this.type == ((RexLocalRef) obj).type
&& this.index == ((RexLocalRef) obj).index;
}
public int hashCode() {
return Objects.hash(type, index);
}
public R accept(RexVisitor visitor) {
return visitor.visitLocalRef(this);
}
public R accept(RexBiVisitor visitor, P arg) {
return visitor.visitLocalRef(this, arg);
}
private static String createName(int index) {
return NAMES.get(index);
}
}
// End RexLocalRef.java