/**
* 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.hadoop.hive.ql.optimizer.calcite.translator;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Stack;
import org.apache.hadoop.hive.ql.ErrorMsg;
import org.apache.hadoop.hive.ql.exec.ColumnInfo;
import org.apache.hadoop.hive.ql.lib.Node;
import org.apache.hadoop.hive.ql.lib.NodeProcessorCtx;
import org.apache.hadoop.hive.ql.parse.ASTNode;
import org.apache.hadoop.hive.ql.parse.BaseSemanticAnalyzer;
import org.apache.hadoop.hive.ql.parse.HiveParser;
import org.apache.hadoop.hive.ql.parse.RowResolver;
import org.apache.hadoop.hive.ql.parse.SemanticException;
import org.apache.hadoop.hive.ql.parse.TypeCheckCtx;
import org.apache.hadoop.hive.ql.parse.TypeCheckProcFactory;
import org.apache.hadoop.hive.ql.plan.ExprNodeColumnDesc;
import org.apache.hadoop.hive.ql.plan.ExprNodeConstantDesc;
import org.apache.hadoop.hive.ql.plan.ExprNodeDesc;
/**
* JoinCondTypeCheckProcFactory is used by Calcite planner(CBO) to generate Join Conditions from Join Condition AST.
* Reasons for sub class:
* 1. Additional restrictions on what is supported in Join Conditions
* 2. Column handling is different
* 3. Join Condn expr has two input RR as opposed to one.
*/
/**
* TODO:<br>
* 1. Could we use combined RR instead of list of RR ?<br>
* 2. Use Column Processing from TypeCheckProcFactory<br>
* 3. Why not use GB expr ?
*/
public class JoinCondTypeCheckProcFactory extends TypeCheckProcFactory {
public static Map<ASTNode, ExprNodeDesc> genExprNode(ASTNode expr, TypeCheckCtx tcCtx)
throws SemanticException {
return TypeCheckProcFactory.genExprNode(expr, tcCtx, new JoinCondTypeCheckProcFactory());
}
/**
* Processor for table columns.
*/
public static class JoinCondColumnExprProcessor extends ColumnExprProcessor {
@Override
public Object process(Node nd, Stack<Node> stack, NodeProcessorCtx procCtx,
Object... nodeOutputs) throws SemanticException {
JoinTypeCheckCtx ctx = (JoinTypeCheckCtx) procCtx;
if (ctx.getError() != null) {
return null;
}
ASTNode expr = (ASTNode) nd;
ASTNode parent = stack.size() > 1 ? (ASTNode) stack.get(stack.size() - 2) : null;
if (expr.getType() != HiveParser.TOK_TABLE_OR_COL) {
ctx.setError(ErrorMsg.INVALID_COLUMN.getMsg(expr), expr);
return null;
}
assert (expr.getChildCount() == 1);
String tableOrCol = BaseSemanticAnalyzer.unescapeIdentifier(expr.getChild(0).getText());
boolean qualifiedAccess = (parent != null && parent.getType() == HiveParser.DOT);
ColumnInfo colInfo = null;
if (!qualifiedAccess) {
colInfo = getColInfo(ctx, null, tableOrCol, expr);
// It's a column.
return new ExprNodeColumnDesc(colInfo);
} else if (hasTableAlias(ctx, tableOrCol, expr)) {
return null;
} else {
// Qualified column access for which table was not found
throw new SemanticException(ErrorMsg.INVALID_TABLE_ALIAS.getMsg(expr));
}
}
private static boolean hasTableAlias(JoinTypeCheckCtx ctx, String tabName, ASTNode expr)
throws SemanticException {
int tblAliasCnt = 0;
for (RowResolver rr : ctx.getInputRRList()) {
if (rr.hasTableAlias(tabName))
tblAliasCnt++;
}
if (tblAliasCnt > 1) {
throw new SemanticException(ErrorMsg.AMBIGUOUS_TABLE_OR_COLUMN.getMsg(expr));
}
return (tblAliasCnt == 1) ? true : false;
}
private static ColumnInfo getColInfo(JoinTypeCheckCtx ctx, String tabName, String colAlias,
ASTNode expr) throws SemanticException {
ColumnInfo tmp;
ColumnInfo cInfoToRet = null;
for (RowResolver rr : ctx.getInputRRList()) {
tmp = rr.get(tabName, colAlias);
if (tmp != null) {
if (cInfoToRet != null) {
throw new SemanticException(ErrorMsg.AMBIGUOUS_TABLE_OR_COLUMN.getMsg(expr));
}
cInfoToRet = tmp;
}
}
return cInfoToRet;
}
}
/**
* Factory method to get ColumnExprProcessor.
*
* @return ColumnExprProcessor.
*/
@Override
public ColumnExprProcessor getColumnExprProcessor() {
return new JoinCondColumnExprProcessor();
}
/**
* The default processor for typechecking.
*/
public static class JoinCondDefaultExprProcessor extends DefaultExprProcessor {
@Override
protected List<String> getReferenceableColumnAliases(TypeCheckCtx ctx) {
JoinTypeCheckCtx jCtx = (JoinTypeCheckCtx) ctx;
List<String> possibleColumnNames = new ArrayList<String>();
for (RowResolver rr : jCtx.getInputRRList()) {
possibleColumnNames.addAll(rr.getReferenceableColumnAliases(null, -1));
}
return possibleColumnNames;
}
@Override
protected ExprNodeColumnDesc processQualifiedColRef(TypeCheckCtx ctx, ASTNode expr,
Object... nodeOutputs) throws SemanticException {
String tableAlias = BaseSemanticAnalyzer.unescapeIdentifier(expr.getChild(0).getChild(0)
.getText());
// NOTE: tableAlias must be a valid non-ambiguous table alias,
// because we've checked that in TOK_TABLE_OR_COL's process method.
ColumnInfo colInfo = getColInfo((JoinTypeCheckCtx) ctx, tableAlias,
((ExprNodeConstantDesc) nodeOutputs[1]).getValue().toString(), expr);
if (colInfo == null) {
ctx.setError(ErrorMsg.INVALID_COLUMN.getMsg(expr.getChild(1)), expr);
return null;
}
return new ExprNodeColumnDesc(colInfo.getType(), colInfo.getInternalName(), tableAlias,
colInfo.getIsVirtualCol());
}
private static ColumnInfo getColInfo(JoinTypeCheckCtx ctx, String tabName, String colAlias,
ASTNode expr) throws SemanticException {
ColumnInfo tmp;
ColumnInfo cInfoToRet = null;
for (RowResolver rr : ctx.getInputRRList()) {
tmp = rr.get(tabName, colAlias);
if (tmp != null) {
if (cInfoToRet != null) {
throw new SemanticException(ErrorMsg.AMBIGUOUS_TABLE_OR_COLUMN.getMsg(expr));
}
cInfoToRet = tmp;
}
}
return cInfoToRet;
}
}
/**
* Factory method to get DefaultExprProcessor.
*
* @return DefaultExprProcessor.
*/
@Override
public DefaultExprProcessor getDefaultExprProcessor() {
return new JoinCondDefaultExprProcessor();
}
}