com.google.zetasql.resolvedast.ResolvedColumn Maven / Gradle / Ivy
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/*
* Copyright 2019 Google LLC
*
* Licensed 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.google.zetasql.resolvedast;
import com.google.common.base.Preconditions;
import com.google.zetasql.Type;
import java.io.Serializable;
import java.util.List;
import java.util.Objects;
/**
* A column produced by part of a query (e.g. a scan or subquery).
*
* This is used in the column_list of a resolved AST node to represent a "slot" in the "tuple"
* produced by that logical operator. This is also used in expressions in ResolvedColumnRef to point
* at the column selected during name resolution.
*
*
The column_id is the definitive identifier for a ResolvedColumn, and the column_id should be
* used to match a ResolvedColumnRef in an expression to the scan that produces that column.
* column_ids are unique within a query. If the same table is scanned multiple times, distinct
* column_ids will be chosen for each scan.
*
*
Joins and other combining nodes may propagate ResolvedColumns from their inputs, with the same
* column_ids.
*/
public final class ResolvedColumn implements Serializable {
private final long id;
private final String tableName;
private final String name;
private final Type type;
// TODO: add annotationMap field after adding full implementation of AnnotationMap.
public ResolvedColumn(long id, String tableName, String name, Type type) {
this.id = id;
this.tableName = Preconditions.checkNotNull(tableName);
this.name = Preconditions.checkNotNull(name);
this.type = Preconditions.checkNotNull(type);
}
public long getId() {
return id;
}
public String getTableName() {
return tableName;
}
public String getName() {
return name;
}
public Type getType() {
return type;
}
public String debugString() {
return tableName + "." + name + "#" + id;
}
public String shortDebugString() {
return name + "#" + id;
}
@Override
public String toString() {
return debugString();
}
public boolean isDefaultValue() {
return id == -1;
}
/**
* Format a list of ResolvedColumns. Uses an abbreviated outputformat if all columns have the same
* tableName.
*
*
The implementation is nearly identical to the C++ implementation in
* ResolvedColumnListToString. Since the outputs must be the same, the implementations should be
* similar to make changes to the output easier.
*/
public static String toString(List columns) {
if (columns.isEmpty()) {
return "[]";
}
String commonTableName = columns.get(0).tableName;
// Use the regular format if we have only one column.
boolean useCommonTableName = columns.size() > 1;
for (int i = 1; i < columns.size(); i++) {
if (!columns.get(i).tableName.equals(commonTableName)) {
useCommonTableName = false;
break;
}
}
StringBuilder sb = new StringBuilder();
if (useCommonTableName) {
sb.append(commonTableName).append(".[");
for (ResolvedColumn column : columns) {
if (column != columns.get(0)) {
sb.append(", ");
}
sb.append(column.shortDebugString());
}
} else {
sb.append("[");
for (ResolvedColumn column : columns) {
if (column != columns.get(0)) {
sb.append(", ");
}
sb.append(column.debugString());
}
}
sb.append("]");
return sb.toString();
}
@Override
/** To provide parity with resolved_column.h, equality is defined using columnId only. */
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o instanceof ResolvedColumn) {
ResolvedColumn other = (ResolvedColumn) o;
return Objects.equals(this.id, other.id);
}
return false;
}
@Override
/** To provide parity with resolved_column.h, hashCode is defined using columnId only. */
public int hashCode() {
return Objects.hashCode(id);
}
}