}
private void assertStringConstant(Expression exp) {
if (exp==null) return;
if (!(exp instanceof ConstantExpression)) {
source.getErrorCollector().addErrorAndContinue(new SyntaxErrorMessage(new SyntaxException(
"Expected a String constant.", exp.getLineNumber(), exp.getColumnNumber()),
source));
}
ConstantExpression ce = (ConstantExpression) exp;
if (!(ce.getValue() instanceof String)) {
source.getErrorCollector().addErrorAndContinue(new SyntaxErrorMessage(new SyntaxException(
"Expected a String constant.", exp.getLineNumber(), exp.getColumnNumber()),
source));
}
}