org.apache.hadoop.hive.ql.parse.HiveSemanticAnalyzerHook Maven / Gradle / Ivy
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* to you under the Apache License, Version 2.0 (the
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* 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
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package org.apache.hadoop.hive.ql.parse;
import java.io.Serializable;
import java.util.List;
import org.apache.hadoop.hive.ql.exec.Task;
import org.apache.hadoop.hive.ql.hooks.Hook;
/**
* HiveSemanticAnalyzerHook allows Hive to be extended with custom
* logic for semantic analysis of QL statements. This interface
* and any Hive internals it exposes are currently
* "limited private and evolving" (unless otherwise stated elsewhere)
* and intended mainly for use by the Howl project.
*
*
*
* Note that the lifetime of an instantiated hook object is scoped to
* the analysis of a single statement; hook instances are never reused.
*/
public interface HiveSemanticAnalyzerHook extends Hook {
/**
* Invoked before Hive performs its own semantic analysis on
* a statement. The implementation may inspect the statement AST and
* prevent its execution by throwing a SemanticException.
* Optionally, it may also augment/rewrite the AST, but must produce
* a form equivalent to one which could have
* been returned directly from Hive's own parser.
*
* @param context context information for semantic analysis
*
* @param ast AST being analyzed and optionally rewritten
*
* @return replacement AST (typically the same as the original AST unless the
* entire tree had to be replaced; must not be null)
*/
public ASTNode preAnalyze(
HiveSemanticAnalyzerHookContext context,
ASTNode ast) throws SemanticException;
/**
* Invoked after Hive performs its own semantic analysis on a
* statement (including optimization).
* Hive calls postAnalyze on the same hook object
* as preAnalyze, so the hook can maintain state across the calls.
*
* @param context context information for semantic analysis
* @param rootTasks root tasks produced by semantic analysis;
* the hook is free to modify this list or its contents
*/
public void postAnalyze(
HiveSemanticAnalyzerHookContext context,
List> rootTasks) throws SemanticException;
}