| // 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.impala.analysis; |
| |
| import org.apache.impala.authorization.Privilege; |
| import org.apache.impala.common.AnalysisException; |
| import org.apache.impala.thrift.TShowTablesParams; |
| |
| import com.google.common.base.Preconditions; |
| |
| /** |
| * Representation of a SHOW TABLES [pattern] statement. |
| * Acceptable syntax: |
| * |
| * SHOW TABLES |
| * SHOW TABLES "pattern" |
| * SHOW TABLES LIKE "pattern" |
| * SHOW TABLES IN database |
| * SHOW TABLES IN database "pattern" |
| * SHOW TABLES IN database LIKE "pattern" |
| * |
| * In Hive, the 'LIKE' is optional. Also SHOW TABLES unquotedpattern is accepted |
| * by the parser but returns no results. We don't support that syntax. |
| */ |
| public class ShowTablesStmt extends StatementBase { |
| // Pattern to match tables against. | denotes choice, * matches all strings |
| private final String pattern_; |
| |
| // DB (if any) as seen by the parser |
| private final String parsedDb_; |
| |
| // Set during analysis |
| private String postAnalysisDb_; |
| |
| /** |
| * Default constructor, which creates a show statement with the default |
| * database and no pattern (which returns all tables in the default database). |
| */ |
| public ShowTablesStmt() { |
| this(null, null); |
| } |
| |
| /** |
| * Constructs a show statement against the default database using the supplied |
| * pattern. |
| */ |
| public ShowTablesStmt(String pattern) { |
| this(null, pattern); |
| } |
| |
| /** |
| * General purpose constructor which builds a show statement that matches |
| * table names against a given pattern in the supplied database. |
| * |
| * If pattern is null, all tables in the supplied database match. |
| * If database is null, the default database is searched. |
| */ |
| public ShowTablesStmt(String database, String pattern) { |
| this.parsedDb_ = database; |
| this.pattern_ = pattern; |
| this.postAnalysisDb_ = null; |
| } |
| |
| public String getPattern() { return pattern_; } |
| |
| /** |
| * Can only be called after analysis, returns the name of the database that |
| * this show will search against. |
| */ |
| public String getDb() { |
| Preconditions.checkNotNull(postAnalysisDb_); |
| return postAnalysisDb_; |
| } |
| |
| @Override |
| public String toSql(ToSqlOptions options) { |
| if (pattern_ == null) { |
| if (parsedDb_ == null) { |
| return "SHOW TABLES"; |
| } else { |
| return "SHOW TABLES IN " + parsedDb_; |
| } |
| } else { |
| if (parsedDb_ == null) { |
| return "SHOW TABLES LIKE '" + pattern_ + "'"; |
| } else { |
| return "SHOW TABLES IN " + parsedDb_ + " LIKE '" + pattern_ + "'"; |
| } |
| } |
| } |
| |
| @Override |
| public void analyze(Analyzer analyzer) throws AnalysisException { |
| postAnalysisDb_ = (parsedDb_ == null ? analyzer.getDefaultDb() : parsedDb_); |
| if (analyzer.getDb(postAnalysisDb_, Privilege.ANY) == null) { |
| throw new AnalysisException(Analyzer.DB_DOES_NOT_EXIST_ERROR_MSG + postAnalysisDb_); |
| } |
| } |
| |
| public TShowTablesParams toThrift() { |
| TShowTablesParams params = new TShowTablesParams(); |
| params.setShow_pattern(getPattern()); |
| params.setDb(getDb()); |
| return params; |
| } |
| } |