/**
* 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.parse;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hive.ql.exec.ColumnInfo;
import org.apache.hadoop.hive.ql.exec.RowSchema;
/**
* Implementation of the Row Resolver.
*
*/
public class RowResolver implements Serializable{
private static final long serialVersionUID = 1L;
private RowSchema rowSchema;
private HashMap<String, LinkedHashMap<String, ColumnInfo>> rslvMap;
private HashMap<String, String[]> invRslvMap;
private Map<String, ASTNode> expressionMap;
// TODO: Refactor this and do in a more object oriented manner
private boolean isExprResolver;
@SuppressWarnings("unused")
private static final Log LOG = LogFactory.getLog(RowResolver.class.getName());
public RowResolver() {
rowSchema = new RowSchema();
rslvMap = new HashMap<String, LinkedHashMap<String, ColumnInfo>>();
invRslvMap = new HashMap<String, String[]>();
expressionMap = new HashMap<String, ASTNode>();
isExprResolver = false;
}
/**
* Puts a resolver entry corresponding to a source expression which is to be
* used for identical expression recognition (e.g. for matching expressions
* in the SELECT list with the GROUP BY clause). The convention for such
* entries is an empty-string ("") as the table alias together with the
* string rendering of the ASTNode as the column alias.
*/
public void putExpression(ASTNode node, ColumnInfo colInfo) {
String treeAsString = node.toStringTree();
expressionMap.put(treeAsString, node);
put("", treeAsString, colInfo);
}
/**
* Retrieves the ColumnInfo corresponding to a source expression which
* exactly matches the string rendering of the given ASTNode.
*/
public ColumnInfo getExpression(ASTNode node) throws SemanticException {
return get("", node.toStringTree());
}
/**
* Retrieves the source expression matching a given ASTNode's
* string rendering exactly.
*/
public ASTNode getExpressionSource(ASTNode node) {
return expressionMap.get(node.toStringTree());
}
public void put(String tab_alias, String col_alias, ColumnInfo colInfo) {
if (tab_alias != null) {
tab_alias = tab_alias.toLowerCase();
}
col_alias = col_alias.toLowerCase();
if (rowSchema.getSignature() == null) {
rowSchema.setSignature(new ArrayList<ColumnInfo>());
}
rowSchema.getSignature().add(colInfo);
LinkedHashMap<String, ColumnInfo> f_map = rslvMap.get(tab_alias);
if (f_map == null) {
f_map = new LinkedHashMap<String, ColumnInfo>();
rslvMap.put(tab_alias, f_map);
}
f_map.put(col_alias, colInfo);
String[] qualifiedAlias = new String[2];
qualifiedAlias[0] = tab_alias;
qualifiedAlias[1] = col_alias;
invRslvMap.put(colInfo.getInternalName(), qualifiedAlias);
}
public boolean hasTableAlias(String tab_alias) {
return rslvMap.get(tab_alias.toLowerCase()) != null;
}
/**
* Gets the column Info to tab_alias.col_alias type of a column reference. I
* the tab_alias is not provided as can be the case with an non aliased
* column, this function looks up the column in all the table aliases in this
* row resolver and returns the match. It also throws an exception if the
* column is found in multiple table aliases. If no match is found a null
* values is returned.
*
* This allows us to interpret both select t.c1 type of references and select
* c1 kind of refereneces. The later kind are what we call non aliased column
* references in the query.
*
* @param tab_alias
* The table alias to match (this is null if the column reference is
* non aliased)
* @param col_alias
* The column name that is being searched for
* @return ColumnInfo
* @throws SemanticException
*/
public ColumnInfo get(String tab_alias, String col_alias) throws SemanticException {
col_alias = col_alias.toLowerCase();
ColumnInfo ret = null;
if (tab_alias != null) {
tab_alias = tab_alias.toLowerCase();
HashMap<String, ColumnInfo> f_map = rslvMap.get(tab_alias);
if (f_map == null) {
return null;
}
ret = f_map.get(col_alias);
} else {
boolean found = false;
for (LinkedHashMap<String, ColumnInfo> cmap : rslvMap.values()) {
for (Map.Entry<String, ColumnInfo> cmapEnt : cmap.entrySet()) {
if (col_alias.equalsIgnoreCase(cmapEnt.getKey())) {
if (found) {
throw new SemanticException("Column " + col_alias
+ " Found in more than One Tables/Subqueries");
}
found = true;
ret = cmapEnt.getValue();
}
}
}
}
return ret;
}
public ArrayList<ColumnInfo> getColumnInfos() {
return rowSchema.getSignature();
}
/**
* Get a list of non-hidden column names
* @param max the maximum number of columns to return
* @return a list of non-hidden column names no greater in size than max
*/
public List<String> getNonHiddenColumnNames(int max) {
List<String> columnNames = new ArrayList<String>();
int count = 0;
for (ColumnInfo columnInfo : getColumnInfos()) {
if (max > 0 && count >= max) {
break;
}
if (!columnInfo.isHiddenVirtualCol()) {
columnNames.add(columnInfo.getInternalName());
count++;
}
}
return columnNames;
}
public HashMap<String, ColumnInfo> getFieldMap(String tabAlias) {
if (tabAlias == null) {
return rslvMap.get(null);
} else {
return rslvMap.get(tabAlias.toLowerCase());
}
}
public int getPosition(String internalName) {
int pos = -1;
for (ColumnInfo var : rowSchema.getSignature()) {
++pos;
if (var.getInternalName().equals(internalName)) {
return pos;
}
}
return -1;
}
public Set<String> getTableNames() {
return rslvMap.keySet();
}
public String[] reverseLookup(String internalName) {
return invRslvMap.get(internalName);
}
public void setIsExprResolver(boolean isExprResolver) {
this.isExprResolver = isExprResolver;
}
public boolean getIsExprResolver() {
return isExprResolver;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
for (Map.Entry<String, LinkedHashMap<String, ColumnInfo>> e : rslvMap
.entrySet()) {
String tab = e.getKey();
sb.append(tab + "{");
HashMap<String, ColumnInfo> f_map = e.getValue();
if (f_map != null) {
for (Map.Entry<String, ColumnInfo> entry : f_map.entrySet()) {
sb.append("(" + entry.getKey() + "," + entry.getValue().toString()
+ ")");
}
}
sb.append("} ");
}
return sb.toString();
}
public RowSchema getRowSchema() {
return rowSchema;
}
public HashMap<String, LinkedHashMap<String, ColumnInfo>> getRslvMap() {
return rslvMap;
}
public HashMap<String, String[]> getInvRslvMap() {
return invRslvMap;
}
public Map<String, ASTNode> getExpressionMap() {
return expressionMap;
}
public void setExprResolver(boolean isExprResolver) {
this.isExprResolver = isExprResolver;
}
public void setRowSchema(RowSchema rowSchema) {
this.rowSchema = rowSchema;
}
public void setRslvMap(HashMap<String, LinkedHashMap<String, ColumnInfo>> rslvMap) {
this.rslvMap = rslvMap;
}
public void setInvRslvMap(HashMap<String, String[]> invRslvMap) {
this.invRslvMap = invRslvMap;
}
public void setExpressionMap(Map<String, ASTNode> expressionMap) {
this.expressionMap = expressionMap;
}
}