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.chemistry.opencmis.server.support.query;
  
  import org.antlr.runtime.BaseRecognizer;
  import org.antlr.runtime.RecognitionException;
  import org.antlr.runtime.TokenStream;
  import org.antlr.runtime.tree.CommonTree;
  import org.antlr.runtime.tree.TreeParser;
  import org.apache.chemistry.opencmis.commons.exceptions.CmisBaseException;
  import org.apache.chemistry.opencmis.commons.exceptions.CmisInvalidArgumentException;
  import org.apache.chemistry.opencmis.server.support.TypeManager;
  
  /**
   * Utility class to help parsing and processing a query statement using the
   * AntLR parser Subclasses have to implement methods that setup parser and query
   * walker and parse and process a query. This class provides common methods for
   * error handling and for storing the necessary opencmis objects for query
   * support
   * 
   * @param <T>
   *            AntLR tree grammar, will usually be a CmisQueryWalker but can be
   *            custom class for customized (extended) parsers
   */
  public abstract class QueryUtilBase<T extends TreeParser> {
  
      protected T walker;
      protected QueryObject queryObj;
      protected PredicateWalkerBase predicateWalker;
      protected String statement;
  
      protected CommonTree parserTree; // the ANTLR tree after parsing phase
      protected TokenStream tokens; // the ANTLR token stream
  
      /**
       * Perform the first phase of query processing. Setup lexer and parser,
       * parse the statement, check for syntax errors and create an AST
       * 
       * @return the abstract syntax tree of the parsed statement
       */
      public abstract CommonTree parseStatement() throws RecognitionException;
  
      /**
       * Perform the second phase of query processing, analyzes the select part,
       * check for semantic errors, fill the query object. Usually a walker will
       * be CmisQueryWalker (or subclass) if the supporting OpenCMIS query classes
       * are used.
       */
      public abstract void walkStatement() throws RecognitionException;
  
      /**
       * Fully process a query by parsing and walking it and setting up the
       * supporting objects
       */
      public void processStatement() throws RecognitionException {
          parseStatement();
          walkStatement();
      }
  
      protected QueryUtilBase(String statement, TypeManager tm, PredicateWalkerBase pw, QueryObject.ParserMode mode) {
          walker = null;
          queryObj = new QueryObject(tm);
          if (mode != null) {
          	queryObj.setSelectMode(mode);
          }
          predicateWalker = pw;
          this.statement = statement;
      }
  
      public T getWalker() {
          return walker;
      }
  
      public PredicateWalkerBase getPredicateWalker() {
          return predicateWalker;
      }
  
      public QueryObject getQueryObject() {
          return queryObj;
      }
  
      public String getStatement() {
          return statement;
      }
  
      /**
       * Same as traverseStatement but throws only CMIS Exceptions
       */
      public void processStatementUsingCmisExceptions() {
          try {
              processStatement();
          } catch (RecognitionException e) {
              String errorMsg = getErrorMessage(e);
              throw new CmisInvalidArgumentException(
                      "Processing of query statement failed with RecognitionException error: \n   " + errorMsg, e);
          } catch (CmisBaseException e) {
              throw e;
          } catch (Exception e) {
              throw new CmisInvalidArgumentException("Processing of query statement failed with exception: "
                      + e.getMessage(), e);
          }
      }
  
      public String getErrorMessage(RecognitionException e) {
          if (null == walker) {
              return e.toString();
          } else {
              return getErrorMessage(walker, e);
          }
      }
  
      private static String getErrorMessage(BaseRecognizer recognizer, RecognitionException e) {
          String[] tokenNames = recognizer.getTokenNames();
          String hdr = "Line " + e.line + ":" + e.charPositionInLine;
          String msg = recognizer.getErrorMessage(e, tokenNames);
          return hdr + " " + msg;
      }
  
  }