ShowFunctionsStmt.java

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// Copyright 2012 Cloudera Inc.
//
// Licensed 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 com.cloudera.impala.analysis;

import com.cloudera.impala.authorization.Privilege;
import com.cloudera.impala.common.AnalysisException;
import com.cloudera.impala.thrift.TFunctionCategory;
import com.cloudera.impala.thrift.TShowFunctionsParams;
import com.google.common.base.Preconditions;

public class ShowFunctionsStmt 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_;

  // Category of functions to be shown. Always set.
  private final TFunctionCategory fnCategory_;

  // Set during analysis
  private String postAnalysisDb_;

  public ShowFunctionsStmt(String db, String pattern, TFunctionCategory fnCategory) {
    Preconditions.checkNotNull(fnCategory);
    parsedDb_ = db;
    pattern_ = pattern;
    fnCategory_ = fnCategory;
  }

  public String getDb() {
    Preconditions.checkNotNull(postAnalysisDb_);
    return postAnalysisDb_;
  }

  public String getPattern() { return pattern_; }

  @Override
  public String toSql() {
    String fnCategory = (fnCategory_ == null) ? "" : fnCategory_.toString() + " ";
    if (pattern_ == null) {
      return "SHOW " + fnCategory + "FUNCTIONS";
    } else {
      return "SHOW " + fnCategory + "FUNCTIONS LIKE '" + pattern_ + "'";
    }
  }

  @Override
  public void analyze(Analyzer analyzer) throws AnalysisException {
    postAnalysisDb_ = (parsedDb_ == null ? analyzer.getDefaultDb() : parsedDb_);
    if (analyzer.getDb(postAnalysisDb_, Privilege.VIEW_METADATA) == null) {
      throw new AnalysisException(Analyzer.DB_DOES_NOT_EXIST_ERROR_MSG + postAnalysisDb_);
    }
  }

  public TShowFunctionsParams toThrift() {
    TShowFunctionsParams params = new TShowFunctionsParams();
    params.setCategory(fnCategory_);
    params.setDb(getDb());
    params.setShow_pattern(getPattern());
    return params;
  }
}