/**
* 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.index;
import java.io.IOException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hive.conf.HiveConf;
import org.apache.hadoop.hive.ql.Context;
import org.apache.hadoop.hive.ql.parse.ASTNode;
import org.apache.hadoop.hive.ql.parse.BaseSemanticAnalyzer;
import org.apache.hadoop.hive.ql.parse.ParseContext;
import org.apache.hadoop.hive.ql.parse.ParseDriver;
import org.apache.hadoop.hive.ql.parse.ParseException;
import org.apache.hadoop.hive.ql.parse.ParseUtils;
import org.apache.hadoop.hive.ql.parse.QB;
import org.apache.hadoop.hive.ql.parse.SemanticAnalyzer;
import org.apache.hadoop.hive.ql.parse.SemanticAnalyzerFactory;
import org.apache.hadoop.hive.ql.parse.SemanticException;
/**
* RewriteParseContextGenerator is a class that offers methods to generate operator tree
* for input queries. It is implemented on lines of the analyzeInternal(..) method
* of {@link SemanticAnalyzer} but it creates only the ParseContext for the input query command.
* It does not optimize or generate map-reduce tasks for the input query.
* This can be used when you need to create operator tree for an internal query.
*
*/
public final class RewriteParseContextGenerator {
private static final Log LOG = LogFactory.getLog(RewriteParseContextGenerator.class.getName());
private RewriteParseContextGenerator(){
}
/**
* Parse the input {@link String} command and generate a ASTNode tree.
* @param conf
* @param command
* @return the parse context
* @throws SemanticException
*/
public static ParseContext generateOperatorTree(HiveConf conf,
String command) throws SemanticException{
Context ctx;
ParseContext subPCtx = null;
try {
ctx = new Context(conf);
ParseDriver pd = new ParseDriver();
ASTNode tree = pd.parse(command, ctx);
tree = ParseUtils.findRootNonNullToken(tree);
BaseSemanticAnalyzer sem = SemanticAnalyzerFactory.get(conf, tree);
assert(sem instanceof SemanticAnalyzer);
doSemanticAnalysis((SemanticAnalyzer) sem, tree, ctx);
subPCtx = ((SemanticAnalyzer) sem).getParseContext();
LOG.info("Sub-query Semantic Analysis Completed");
} catch (IOException e) {
LOG.error("IOException in generating the operator " +
"tree for input command - " + command + " " , e);
LOG.error(org.apache.hadoop.util.StringUtils.stringifyException(e));
throw new SemanticException(e.getMessage(), e);
} catch (ParseException e) {
LOG.error("ParseException in generating the operator " +
"tree for input command - " + command + " " , e);
LOG.error(org.apache.hadoop.util.StringUtils.stringifyException(e));
throw new SemanticException(e.getMessage(), e);
} catch (SemanticException e) {
LOG.error("SemanticException in generating the operator " +
"tree for input command - " + command + " " , e);
LOG.error(org.apache.hadoop.util.StringUtils.stringifyException(e));
throw new SemanticException(e.getMessage(), e);
}
return subPCtx;
}
/**
* For the input ASTNode tree, perform a semantic analysis and check metadata
* Generate a operator tree and return the {@link ParseContext} instance for the operator tree.
*
* @param ctx
* @param sem
* @param ast
* @return
* @throws SemanticException
*/
private static void doSemanticAnalysis(SemanticAnalyzer sem,
ASTNode ast, Context ctx) throws SemanticException {
QB qb = new QB(null, null, false);
ASTNode child = ast;
ParseContext subPCtx = ((SemanticAnalyzer) sem).getParseContext();
subPCtx.setContext(ctx);
((SemanticAnalyzer) sem).initParseCtx(subPCtx);
LOG.info("Starting Sub-query Semantic Analysis");
sem.doPhase1(child, qb, sem.initPhase1Ctx());
LOG.info("Completed phase 1 of Sub-query Semantic Analysis");
sem.getMetaData(qb);
LOG.info("Completed getting MetaData in Sub-query Semantic Analysis");
LOG.info("Sub-query Abstract syntax tree: " + ast.toStringTree());
sem.genPlan(qb);
LOG.info("Sub-query Completed plan generation");
}
}