private AST createFromElement(String text) {
AST ast =
ASTUtil.create(
fromClause.getASTFactory(),
implied
? IMPLIED_FROM
: FROM_FRAGMENT, // This causes the factory to instantiate the desired class.
text);
// Reset the node type, because the rest of the system is expecting FROM_FRAGMENT, all we wanted
// was
// for the factory to create the right sub-class. This might get reset again later on anyway to
// make the
// SQL generation simpler.
ast.setType(FROM_FRAGMENT);
return ast;
}
/**
* Returns an equivalent tree for (NOT (a relop b) ), for example:
*
* <pre>
* (NOT (GT a b) ) => (LE a b)
* </pre>
*
* @param x The sub tree to transform, the parent is assumed to be NOT.
* @return AST - The equivalent sub-tree.
*/
public AST negateNode(AST x) {
// TODO: switch statements are always evil! We already had bugs because
// of forgotten token types. Use polymorphism for this!
switch (x.getType()) {
case OR:
x.setType(AND);
x.setText("{and}");
negateNode(x.getFirstChild());
negateNode(x.getFirstChild().getNextSibling());
return x;
case AND:
x.setType(OR);
x.setText("{or}");
negateNode(x.getFirstChild());
negateNode(x.getFirstChild().getNextSibling());
return x;
case EQ:
x.setType(NE);
x.setText("{not}" + x.getText());
return x; // (NOT (EQ a b) ) => (NE a b)
case NE:
x.setType(EQ);
x.setText("{not}" + x.getText());
return x; // (NOT (NE a b) ) => (EQ a b)
case GT:
x.setType(LE);
x.setText("{not}" + x.getText());
return x; // (NOT (GT a b) ) => (LE a b)
case LT:
x.setType(GE);
x.setText("{not}" + x.getText());
return x; // (NOT (LT a b) ) => (GE a b)
case GE:
x.setType(LT);
x.setText("{not}" + x.getText());
return x; // (NOT (GE a b) ) => (LT a b)
case LE:
x.setType(GT);
x.setText("{not}" + x.getText());
return x; // (NOT (LE a b) ) => (GT a b)
case LIKE:
x.setType(NOT_LIKE);
x.setText("{not}" + x.getText());
return x; // (NOT (LIKE a b) ) => (NOT_LIKE a b)
case NOT_LIKE:
x.setType(LIKE);
x.setText("{not}" + x.getText());
return x; // (NOT (NOT_LIKE a b) ) => (LIKE a b)
case IN:
x.setType(NOT_IN);
x.setText("{not}" + x.getText());
return x;
case NOT_IN:
x.setType(IN);
x.setText("{not}" + x.getText());
return x;
case IS_NULL:
x.setType(IS_NOT_NULL);
x.setText("{not}" + x.getText());
return x; // (NOT (IS_NULL a b) ) => (IS_NOT_NULL a b)
case IS_NOT_NULL:
x.setType(IS_NULL);
x.setText("{not}" + x.getText());
return x; // (NOT (IS_NOT_NULL a b) ) => (IS_NULL a b)
case BETWEEN:
x.setType(NOT_BETWEEN);
x.setText("{not}" + x.getText());
return x; // (NOT (BETWEEN a b) ) => (NOT_BETWEEN a b)
case NOT_BETWEEN:
x.setType(BETWEEN);
x.setText("{not}" + x.getText());
return x; // (NOT (NOT_BETWEEN a b) ) => (BETWEEN a b)
/* This can never happen because this rule will always eliminate the child NOT.
case NOT:
return x.getFirstChild(); // (NOT (NOT x) ) => (x)
*/
default:
return super.negateNode(x); // Just add a 'not' parent.
}
}
public void initializeMethodNode(AST name, boolean inSelect) {
name.setType(SqlTokenTypes.METHOD_NAME);
String text = name.getText();
methodName = text.toLowerCase(); // Use the lower case function name.
this.inSelect = inSelect; // Remember whether we're in a SELECT clause or not.
}
