Пример #1
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    @Override
    public int _handleToken(ParseContext ctx) throws InvalidQueryException {
      Token token = ctx.getTokens()[ctx.getCurrentTokensIndex()];
      ctx.getPrecedingExpression().setLeftOperand(token.getValue());

      return 1;
    }
Пример #2
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  /**
   * Generate a Predicate instance from an array of tokens. Each input token contains a type and a
   * value.
   *
   * <p>Based on the token type and location, the tokens are first translated into a list of
   * expressions, both relational and logical. These expressions are then merged into a tree of
   * expressions with a single root following operator precedence and explicit grouping rules.
   * Depending on the query, this merging of expressions into a tree of expressions may occur in
   * several passes, one pass per level of precedence starting at the highest level of precedence.
   *
   * <p>The predicate is built by traversing the expression tree in-order with each node expressing
   * itself as a predicate.
   *
   * @param tokens an array of tokens which represent the query, each token contains type and value
   *     information
   * @return a new predicate instance based on the supplied tokens
   * @throws InvalidQueryException if unable to parse the tokens and produce a predicate
   */
  public Predicate parse(Token[] tokens) throws InvalidQueryException {
    ParseContext ctx = parseExpressions(tokens);

    List<Expression> listExpressions = ctx.getExpressions();
    List<Expression> listMergedExpressions =
        mergeExpressions(listExpressions, ctx.getMaxPrecedence());

    return listMergedExpressions.isEmpty() ? null : listMergedExpressions.get(0).toPredicate();
  }
Пример #3
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    @Override
    public int _handleToken(ParseContext ctx) throws InvalidQueryException {
      Token token = ctx.getTokens()[ctx.getCurrentTokensIndex()];
      RelationalOperator relationalOp = RelationalOperatorFactory.createOperator(token.getValue());
      // todo: use factory to create expression
      ctx.addExpression(new RelationalExpression(relationalOp));

      return 1;
    }
Пример #4
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    @Override
    public int _handleToken(ParseContext ctx) throws InvalidQueryException {
      Token token = ctx.getTokens()[ctx.getCurrentTokensIndex()];
      LogicalOperator logicalOp =
          LogicalOperatorFactory.createOperator(token.getValue(), ctx.getPrecedenceLevel());
      ctx.updateMaxPrecedence(logicalOp.getPrecedence());
      ctx.addExpression(LogicalExpressionFactory.createLogicalExpression(logicalOp));

      return 1;
    }
Пример #5
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  /**
   * Create parse context from an array of tokens. The parse context contains a list of expressions
   * and other information about the expressions an parsed tokens.
   *
   * @param tokens an array of tokens which represent the query, each token contains type and value
   *     information
   * @return a parse context which contains a list of expressions
   * @throws InvalidQueryException if unable to properly parse the tokens into a parse context
   */
  private ParseContext parseExpressions(Token[] tokens) throws InvalidQueryException {
    ParseContext ctx = new ParseContext(tokens);

    while (ctx.getCurrentTokensIndex() < tokens.length) {
      TOKEN_HANDLERS.get(tokens[ctx.getCurrentTokensIndex()].getType()).handleToken(ctx);
    }

    if (ctx.getPrecedenceLevel() != 0) {
      throw new InvalidQueryException("Invalid query string: mismatched parentheses.");
    }

    return ctx;
  }
Пример #6
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    @Override
    public int _handleToken(ParseContext ctx) throws InvalidQueryException {
      Token[] tokens = ctx.getTokens();
      int idx = ctx.getCurrentTokensIndex();
      Token token = tokens[idx];
      RelationalOperator relationalOp = RelationalOperatorFactory.createOperator(token.getValue());

      ctx.addExpression(new RelationalExpression(relationalOp));
      ctx.setCurrentTokensIndex(++idx);

      TokenHandler propertyHandler = new PropertyOperandTokenHandler();
      propertyHandler.handleToken(ctx);

      // handle right operand if applicable to operator
      idx = ctx.getCurrentTokensIndex();
      if (ctx.getCurrentTokensIndex() < tokens.length
          && tokens[idx].getType().equals(Token.TYPE.VALUE_OPERAND)) {
        TokenHandler valueHandler = new ValueOperandTokenHandler();
        valueHandler.handleToken(ctx);
      }

      // skip closing bracket
      idx = ctx.getCurrentTokensIndex();
      if (idx >= tokens.length || tokens[idx].getType() != Token.TYPE.BRACKET_CLOSE) {
        throw new InvalidQueryException("Missing closing bracket for in expression.");
      }
      return 1;
    }
Пример #7
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    /**
     * Process a token. Handles common token processing functionality then delegates to the
     * individual concrete handlers.
     *
     * @param ctx the current parse context
     * @throws InvalidQueryException if unable to process the token
     */
    public void handleToken(ParseContext ctx) throws InvalidQueryException {
      Token token = ctx.getTokens()[ctx.getCurrentTokensIndex()];
      if (!validate(ctx.getPreviousTokenType())) {
        throw new InvalidQueryException(
            "Unexpected token encountered in query string. Last Token Type="
                + ctx.getPreviousTokenType()
                + ", Current Token[type="
                + token.getType()
                + ", value='"
                + token.getValue()
                + "']");
      }
      ctx.setTokenType(token.getType());

      int idxIncrement = _handleToken(ctx);
      ctx.setCurrentTokensIndex(ctx.getCurrentTokensIndex() + idxIncrement);
    }
Пример #8
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    @Override
    public int _handleToken(ParseContext ctx) throws InvalidQueryException {
      ctx.decPrecedenceLevel(Operator.MAX_OP_PRECEDENCE);

      return 1;
    }
Пример #9
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 @Override
 public int _handleToken(ParseContext ctx) {
   ctx.incPrecedenceLevel(Operator.MAX_OP_PRECEDENCE);
   return 1;
 }