Package org.apache.derby.iapi.sql.compile

Interface ASTVisitor

  • All Superinterfaces:
    Visitor
    public interface ASTVisitor
extends Visitor

    A Visitor which handles nodes in Derby's abstract syntax trees. In addition to this contract, it is expected that an ASTVisitor will have a 0-arg constructor. You use an ASTVisitor like this: 

     // initialize your visitor
 MyASTVisitor myVisitor = new MyASTVisitor();
 myVisitor.initializeVisitor();
 languageConnectionContext.setASTVisitor( myVisitor );

 // then run your queries.
 ...

 // when you're done inspecting query trees, release resources and
 // remove your visitor
 languageConnectionContext.setASTVisitor( null );
 myVisitor.teardownVisitor();

    • Method Detail

      • initializeVisitor

        void initializeVisitor()
                throws StandardException
        Initialize the Visitor before processing any trees. User-written code calls this method before poking the Visitor into the LanguageConnectionContext. For example, an implementation of this method might open a trace file.
        Throws:
        StandardException

      • teardownVisitor

        void teardownVisitor()
              throws StandardException
        Final call to the Visitor. User-written code calls this method when it is done inspecting query trees. For instance, an implementation of this method might release resources, closing files it has opened.
        Throws:
        StandardException

      • begin

        void begin​(java.lang.String statementText,
           int phase)
    throws StandardException
        The compiler calls this method just before walking a query tree.
        Parameters:
        statementText - Text used to create the tree.
        phase - of compilation (AFTER_PARSE, AFTER_BIND, or AFTER_OPTIMIZE).
        Throws:
        StandardException

      • end

        void end​(int phase)
  throws StandardException
        The compiler calls this method when it's done walking a tree.
        Parameters:
        phase - of compilation (AFTER_PARSE, AFTER_BIND, or AFTER_OPTIMIZE).
        Throws:
        StandardException