@SuppressWarnings("unchecked")
private void expression() {
term();
while (token == Lexer.OR) {
NonTerminal or = NodeFactory.createNonTerminal(token);
or.setLeft(root);
term();
or.setRight(root);
root = or;
}
}
@SuppressWarnings("unchecked")
private void term() {
factor();
while (token == Lexer.AND) {
NonTerminal and = NodeFactory.createNonTerminal(token);
and.setLeft(root);
factor();
and.setRight(root);
root = and;
}
}
private void value() {
if (token == Lexer.VARIABLE || token == Lexer.NUMBER) {
root = NodeFactory.createTerminal(token, lexer.getValue());
if (token == Lexer.VARIABLE && allowedIdentifiers != null) {
if (!allowedIdentifiers.contains(root.getSymbol()))
throw new MalformedExpressionException(
String.format("Unknown identifier '%s'", root.getSymbol()));
}
token = lexer.nextToken();
} else {
throw new MalformedExpressionException(
String.format("Value instead of <%s> expected.", token));
}
}
@SuppressWarnings("unchecked")
private void condition() {
value();
if (token == Lexer.GREATER
|| token == Lexer.GREATEROREQUAL
|| token == Lexer.LESS
|| token == Lexer.LESSOREQUAL
|| token == Lexer.EQUAL
|| token == Lexer.NOTEQUAL) {
NonTerminal condition = NodeFactory.createNonTerminal(token);
condition.setLeft(root);
token = lexer.nextToken();
value();
condition.setRight(root);
root = condition;
} else {
throw new MalformedExpressionException(
String.format("Conditional operator instead of <%s> expected.", token));
}
}