content: /*
   * 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.cassandra.cql3;
  
  import org.antlr.runtime.ANTLRStringStream;
  import org.antlr.runtime.CharStream;
  import org.antlr.runtime.CommonTokenStream;
  import org.antlr.runtime.RecognitionException;
  import org.antlr.runtime.TokenStream;
  import org.apache.cassandra.exceptions.SyntaxException;
  
  /**
   * Helper class to encapsulate common code that calls one of the generated methods in {@code CqlParser}.
   */
  public final class CQLFragmentParser
  {
  
      @FunctionalInterface
      public interface CQLParserFunction<R>
      {
          R parse(CqlParser parser) throws RecognitionException;
      }
  
      public static <R> R parseAny(CQLParserFunction<R> parserFunction, String input, String meaning)
      {
          try
          {
              return parseAnyUnhandled(parserFunction, input);
          }
          catch (RuntimeException re)
          {
              throw new SyntaxException(String.format("Failed parsing %s: [%s] reason: %s %s",
                                                      meaning,
                                                      input,
                                                      re.getClass().getSimpleName(),
                                                      re.getMessage()));
          }
          catch (RecognitionException e)
          {
              throw new SyntaxException("Invalid or malformed " + meaning + ": " + e.getMessage());
          }
      }
  
      /**
       * Just call a parser method in {@link CqlParser} - does not do any error handling.
       */
      public static <R> R parseAnyUnhandled(CQLParserFunction<R> parserFunction, String input) throws RecognitionException
      {
          // Lexer and parser
          ErrorCollector errorCollector = new ErrorCollector(input);
          CharStream stream = new ANTLRStringStream(input);
          CqlLexer lexer = new CqlLexer(stream);
          lexer.addErrorListener(errorCollector);
  
          TokenStream tokenStream = new CommonTokenStream(lexer);
          CqlParser parser = new CqlParser(tokenStream);
          parser.addErrorListener(errorCollector);
  
          // Parse the query string to a statement instance
          R r = parserFunction.parse(parser);
  
          // The errorCollector has queue up any errors that the lexer and parser may have encountered
          // along the way, if necessary, we turn the last error into exceptions here.
          errorCollector.throwFirstSyntaxError();
  
          return r;
      }
  }
  