Package org.h2.bnf

Class Bnf

java.lang.Object
org.h2.bnf.Bnf
public class Bnf extends Object
This class can read a file that is similar to BNF (Backus-Naur form). It is made specially to support SQL grammar.

  • Constructor Details

    • Bnf

      public Bnf()

  • Method Details

    • getInstance

      public static Bnf getInstance(Reader csv) throws SQLException, IOException
      Create an instance using the grammar specified in the CSV file.
      Parameters:
      csv - if not specified, the help.csv is used
      Returns:
      a new instance
      Throws:
      SQLException - on failure
      IOException - on failure

    • addAlias

      public void addAlias(String name, String replacement)
      Add an alias for a rule.
      Parameters:
      name - for example "procedure"
      replacement - for example "@func@"

    • visit

      public void visit(BnfVisitor visitor, String s)
      Parse the syntax and let the rule call the visitor.
      Parameters:
      visitor - the visitor
      s - the syntax to parse

    • startWithSpace

      public static boolean startWithSpace(String s)
      Check whether the statement starts with a whitespace.
      Parameters:
      s - the statement
      Returns:
      if the statement is not empty and starts with a whitespace

    • getRuleMapKey

      public static String getRuleMapKey(String token)
      Convert convert ruleLink to rule_link.
      Parameters:
      token - the token
      Returns:
      the rule map key

    • getRuleHead

      public RuleHead getRuleHead(String title)
      Get the rule head for the given title.
      Parameters:
      title - the title
      Returns:
      the rule head, or null

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • getNextTokenList

      public HashMap<String,String> getNextTokenList(String query)
      Get the list of tokens that can follow. This is the main autocomplete method. The returned map for the query 'S' may look like this: 
       key: 1#SELECT, value: ELECT
 key: 1#SET, value: ET
      Parameters:
      query - the start of the statement
      Returns:
      the map of possible token types / tokens

    • linkStatements

      public void linkStatements()
      Cross-link all statements with each other. This method is called after updating the topics.

    • updateTopic

      public void updateTopic(String topic, DbContextRule rule)
      Update a topic with a context specific rule. This is used for autocomplete support.
      Parameters:
      topic - the topic
      rule - the database context rule

    • getStatements

      public ArrayList<RuleHead> getStatements()
      Get the list of possible statements.
      Returns:
      the list of statements

    • getTokenizer

      public static StringTokenizer getTokenizer(String s)
      Get the tokenizer for the given syntax.
      Parameters:
      s - the syntax
      Returns:
      the tokenizer