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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.lens.driver.es;
import java.util.ArrayList;
import java.util.List;
import org.apache.lens.cube.parse.HQLParser;
import org.apache.lens.driver.es.exceptions.InvalidQueryException;
import org.apache.lens.driver.es.translator.ASTCriteriaVisitor;
import org.apache.lens.driver.es.translator.ASTVisitor;
import org.apache.lens.driver.es.translator.CriteriaVisitorFactory;
import org.apache.lens.server.api.error.LensException;
import org.apache.commons.lang3.Validate;
import org.apache.hadoop.hive.ql.lib.Node;
import org.apache.hadoop.hive.ql.parse.ASTNode;
import org.apache.hadoop.hive.ql.parse.HiveParser;
import com.google.common.collect.Lists;
import lombok.NonNull;
import lombok.RequiredArgsConstructor;
/**
* This traverses ASTNode in inorder fashion.
* More visitors (translation/validation) can be added.
* Any SQL query can be converted to ASTNode and can be traversed using this traversal
*
* Currently this traversal is limited for elastic search. So naming it this way.
*
* Look at the constructor for usage.
*/
@RequiredArgsConstructor
public final class ASTTraverserForES {
/**
* the root node of the ASTNode
*/
@NonNull
private final ASTNode rootQueryNode;
/**
* The basic query visitor
*/
@NonNull
private final ASTVisitor visitor;
/**
* the criteria visitor factory,
* traversal has to create multiple criteria visitor objects for
* nested criteria. The impl of factory would determine the type of
* criteria visitor
*/
@NonNull
private final CriteriaVisitorFactory criteriaVisitorFactory;
public void accept() throws InvalidQueryException {
traverseSelects();
traverseTableName();
traverseCriteria();
traverseGroupBy();
traverseOrderBy();
traverseLimit();
visitor.completeVisit();
}
/**
* Visit select expressions
*/
public void traverseSelects() throws InvalidQueryException {
final ASTNode selectNode = HQLParser.findNodeByPath(rootQueryNode, HiveParser.TOK_INSERT, HiveParser.TOK_SELECT);
if (selectNode == null) {
throw new InvalidQueryException("No columns are selected!");
}
try {
for (Node selectExp : selectNode.getChildren()) {
final Node innerNode = Helper.getFirstChild(selectExp);
final String alias = Helper.getAliasFromSelectExpr(selectExp);
if (innerNode.getName().equals(String.valueOf(HiveParser.TOK_FUNCTION))) {
Validate.isTrue(innerNode.getChildren().size() == 2);
visitor.visitAggregation(
Helper.getFirstChild(innerNode).toString(),
Helper.getColumnNameFrom(innerNode.getChildren().get(1)),
alias
);
} else if (innerNode.getName().equals(String.valueOf(HiveParser.TOK_ALLCOLREF))) {
visitor.visitAllCols();
} else if (innerNode.getName().equals(String.valueOf(HiveParser.TOK_TABLE_OR_COL))
|| innerNode.toString().equals(".")) {
visitor.visitSimpleSelect(
Helper.getColumnNameFrom(innerNode),
alias
);
} else {
throw new InvalidQueryException(selectExp.getName() + " seems to be invalid");
}
}
} catch (Exception e) {
throw new InvalidQueryException("Exception while traversing select expressions", e);
}
}
/**
* Visit table name
*/
private void traverseTableName() throws InvalidQueryException {
try {
final ASTNode dbSchemaTable = HQLParser.findNodeByPath(
rootQueryNode,
HiveParser.TOK_FROM,
HiveParser.TOK_TABREF,
HiveParser.TOK_TABNAME);
Validate.notNull(dbSchemaTable, "Index and type not present");
Validate.isTrue(dbSchemaTable.getChildren().size() == 2, "Index and type not present");
final String dbSchema = dbSchemaTable.getChild(0).getText();
final String tableName = dbSchemaTable.getChild(1).getText();
visitor.visitFrom(dbSchema, tableName);
} catch (Exception e) {
throw new InvalidQueryException("Error while traversing table name "
+ "- Expected grammar .. from .", e);
}
}
/**
* Visit criteria
*/
private void traverseCriteria() throws InvalidQueryException {
try {
final ASTNode criteriaNode = HQLParser.findNodeByPath(rootQueryNode,
HiveParser.TOK_INSERT, HiveParser.TOK_WHERE);
if (criteriaNode != null) {
visitor.visitCriteria(traverseCriteriaRecursively(Helper.getFirstChild(criteriaNode)));
}
} catch (Exception e) {
throw new InvalidQueryException("Exception while traversing criteria", e);
}
}
private ASTCriteriaVisitor traversePredicate(Node whereClause, PredicateInfo predicateInfo)
throws InvalidQueryException {
final ASTCriteriaVisitor childVisitor = criteriaVisitorFactory.getInstance();
final ArrayList rightExpressions = Lists.newArrayList();
final List rightExpList = whereClause.getChildren();
String leftCol;
switch (predicateInfo.predicateType) {
case BETWEEN:
Validate.isTrue(rightExpList.size()==5, "Atleast one right expression needed");
rightExpressions.add(whereClause.getChildren().get(3).toString());
rightExpressions.add(whereClause.getChildren().get(4).toString());
leftCol = whereClause.getChildren().get(2).getChildren().get(1).toString();
break;
case IN:
case NOT_IN:
Validate.isTrue(rightExpList.size()>2, "Atleast one right expression needed");
for (Node node : whereClause.getChildren().subList(2, whereClause.getChildren().size())) {
rightExpressions.add(node.toString());
}
leftCol = whereClause.getChildren().get(1).getChildren().get(0).toString();
break;
case SIMPLE:
Validate.isTrue(rightExpList.size()>1, "Atleast one right expression needed");
for(Node rightExp : rightExpList.subList(1, rightExpList.size())) {
rightExpressions.add(rightExp.toString());
}
leftCol = Helper.getLeftColFromPredicate(whereClause);
break;
default:
throw new InvalidQueryException("No handlers for predicate " + predicateInfo.predicateType);
}
childVisitor.visitPredicate(predicateInfo.predicateOp
, leftCol
, rightExpressions);
return childVisitor;
}
private ASTCriteriaVisitor traverseLogicalOperator(Node whereClause, LogicalOpInfo logicalOpInfo)
throws InvalidQueryException {
final ASTCriteriaVisitor childVisitor = criteriaVisitorFactory.getInstance();
final List childVisitors = Lists.newArrayList();
for (Node node : whereClause.getChildren()) {
childVisitors.add(traverseCriteriaRecursively(node));
}
childVisitor.visitLogicalOp(logicalOpInfo.logicalOperator, childVisitors);
return childVisitor;
}
private ASTCriteriaVisitor traverseCriteriaRecursively(Node whereClause) throws InvalidQueryException {
final CriteriaInfo criteriaInfo = Helper.getCriteriaInfo(whereClause);
switch (criteriaInfo.criteriaType) {
case PREDICATE:
return traversePredicate(whereClause, (PredicateInfo) criteriaInfo);
case LOGICAL:
return traverseLogicalOperator(whereClause, (LogicalOpInfo) criteriaInfo);
default:
throw new InvalidQueryException("Expecting a predicate or logical operator but got this "
+ whereClause.toString());
}
}
/**
* Visit group by
*/
private void traverseGroupBy() throws InvalidQueryException {
try {
final ASTNode groupByNode = HQLParser.findNodeByPath(rootQueryNode,
HiveParser.TOK_INSERT, HiveParser.TOK_GROUPBY);
if (groupByNode != null) {
for (Node groupBy : groupByNode.getChildren()) {
visitor.visitGroupBy(Helper.getColumnNameFrom(groupBy));
}
}
} catch (Exception e) {
throw new InvalidQueryException("Exception while parsing group by", e);
}
}
/**
* Visit order by
*/
private void traverseOrderBy() throws InvalidQueryException {
try {
final ASTNode orderByNode = HQLParser.findNodeByPath(rootQueryNode,
HiveParser.TOK_INSERT, HiveParser.TOK_ORDERBY);
if (orderByNode != null) {
for (Node orderBy : orderByNode.getChildren()) {
visitor.visitOrderBy(
Helper.getColumnNameFrom(Helper.getFirstChild(orderBy)),
orderBy.getName().equals(String.valueOf(HiveParser.TOK_TABSORTCOLNAMEDESC))
?
ASTVisitor.OrderBy.DESC
:
ASTVisitor.OrderBy.ASC
);
}
}
} catch (Exception e) {
throw new InvalidQueryException("Exception while parsing order by", e);
}
}
/**
* Visit limit
*/
private void traverseLimit() throws InvalidQueryException {
try {
final ASTNode limitNode = HQLParser.findNodeByPath(rootQueryNode,
HiveParser.TOK_INSERT, HiveParser.TOK_LIMIT);
if (limitNode != null) {
visitor.visitLimit(Integer.parseInt(Helper.getFirstChild(limitNode).toString()));
}
} catch (Exception e) {
throw new InvalidQueryException("Error while parsing limit, format should be limit ", e);
}
}
private enum PredicateType {SIMPLE, IN, NOT_IN, BETWEEN};
private enum CriteriaType {PREDICATE, LOGICAL}
private enum LogicalOpType {UNARY, BINARY}
private static class CriteriaInfo {
final CriteriaType criteriaType;
public CriteriaInfo(CriteriaType criteriaType) {
this.criteriaType = criteriaType;
}
}
private static class LogicalOpInfo extends CriteriaInfo{
final String logicalOperator;
final LogicalOpType logicalOpType;
public LogicalOpInfo(String logicalOperator, LogicalOpType logicalOpType) {
super(CriteriaType.LOGICAL);
this.logicalOperator = logicalOperator;
this.logicalOpType = logicalOpType;
}
}
private static class PredicateInfo extends CriteriaInfo {
final PredicateType predicateType;
final String predicateOp;
public PredicateInfo(String operator, PredicateType predicateType) {
super(CriteriaType.PREDICATE);
this.predicateType = predicateType;
this.predicateOp = operator;
}
}
private static class Helper {
private static List predicates
= Lists.newArrayList("!=", "=", ">", "<", "<=", ">=", "between", "in", "not in");
private static List unaryLogicalOps = Lists.newArrayList("not", "!");
private static List binaryLogicalOps = Lists.newArrayList("and", "or", "&", "|", "&&", "||");
private static List logicalOps = Lists.newArrayList();
static {
logicalOps.addAll(unaryLogicalOps);
logicalOps.addAll(binaryLogicalOps);
}
private static String getAliasFromSelectExpr(Node selectExp) {
return selectExp.getChildren().size() == 2
?
selectExp.getChildren().get(1).toString()
:
null;
}
private static CriteriaInfo getCriteriaInfo(Node whereClause) throws InvalidQueryException {
String whereRoot = whereClause.toString();
if (Helper.unaryLogicalOps.contains(whereRoot)) {
return new LogicalOpInfo(whereRoot, LogicalOpType.UNARY);
} else if (Helper.binaryLogicalOps.contains(whereRoot)) {
return new LogicalOpInfo(whereRoot, LogicalOpType.BINARY);
} else if (Helper.predicates.contains(whereRoot)) {
return new PredicateInfo(whereRoot, PredicateType.SIMPLE);
} else if (whereRoot.equals("TOK_FUNCTION") && whereClause.getChildren().get(0).toString().equals("between")) {
return new PredicateInfo("between", PredicateType.BETWEEN);
} else if (whereRoot.equals("TOK_FUNCTION") && whereClause.getChildren().get(0).toString().equals("in")) {
return new PredicateInfo("in", PredicateType.IN);
} else if (whereRoot.equals("TOK_FUNCTION") && whereClause.getChildren().get(0).toString().equals("not in")) {
return new PredicateInfo("not in", PredicateType.NOT_IN);
} else {
throw new InvalidQueryException("Could not get criteria info for where clause " + whereRoot);
}
}
private static Node getFirstChild(Node node) throws LensException {
try {
return node.getChildren().get(0);
} catch (Exception e) {
throw new LensException("Expecting a non empty first child for " + node.toString(), e);
}
}
private static String getLeftColFromPredicate(Node predicateNode) throws InvalidQueryException {
try {
return getColumnNameFrom(getFirstChild(predicateNode));
} catch (Exception e) {
throw new InvalidQueryException("Only simple predicates of the grammar
= is supported as of now", e);
}
}
private static String getColumnNameFrom(Node columnNode) {
final StringBuilder stringBuilder = new StringBuilder();
HQLParser.toInfixString((ASTNode) columnNode, stringBuilder);
return stringBuilder.toString().replaceAll("[() ]", "");
}
}
}
