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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
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 */
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:
* 1. Could we use combined RR instead of list of RR ?
* 2. Use Column Processing from TypeCheckProcFactory
* 3. Why not use GB expr ? */ public class JoinCondTypeCheckProcFactory extends TypeCheckProcFactory { public static Map 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 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 getReferenceableColumnAliases(TypeCheckCtx ctx) { JoinTypeCheckCtx jCtx = (JoinTypeCheckCtx) ctx; List possibleColumnNames = new ArrayList(); 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(); } }




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