I am trying to comment a particulate statement.
My first approach is to return a comment in case statement is an 'Expression Statement' and expression is a particular 'Method Call Expression'.
new ModifierVisitor<Object>() {
public Visitable visit(ExpressionStmt expStmt, Object arg) {
Expression exp = expStmt.getExpression();
if (exp.isMethodCallExpr()) {
// My other logic goes here
return new LineComment(expStmt.toString());
}
}
}
But it failed while dumping the unit back to string.
java.lang.ClassCastException: com.github.javaparser.ast.comments.LineComment cannot be cast to com.github.javaparser.ast.stmt.Statement
at com.github.javaparser.printer.DefaultPrettyPrinterVisitor.visit(DefaultPrettyPrinterVisitor.java:1329)
at com.github.javaparser.printer.DefaultPrettyPrinterVisitor.visit(DefaultPrettyPrinterVisitor.java:163)
at com.github.javaparser.ast.stmt.BlockStmt.accept(BlockStmt.java:76)
at com.github.javaparser.printer.DefaultPrettyPrinterVisitor.visit(DefaultPrettyPrinterVisitor.java:1220)
at com.github.javaparser.printer.DefaultPrettyPrinterVisitor.visit(DefaultPrettyPrinterVisitor.java:163)
at com.github.javaparser.ast.body.MethodDeclaration.accept(MethodDeclaration.java:104)
at com.github.javaparser.printer.DefaultPrettyPrinterVisitor.printMembers(DefaultPrettyPrinterVisitor.java:190)
at com.github.javaparser.printer.DefaultPrettyPrinterVisitor.visit(DefaultPrettyPrinterVisitor.java:419)
at com.github.javaparser.printer.DefaultPrettyPrinterVisitor.visit(DefaultPrettyPrinterVisitor.java:163)
at com.github.javaparser.ast.body.ClassOrInterfaceDeclaration.accept(ClassOrInterfaceDeclaration.java:98)
at com.github.javaparser.printer.DefaultPrettyPrinterVisitor.visit(DefaultPrettyPrinterVisitor.java:325)
at com.github.javaparser.printer.DefaultPrettyPrinterVisitor.visit(DefaultPrettyPrinterVisitor.java:163)
at com.github.javaparser.ast.CompilationUnit.accept(CompilationUnit.java:133)
at com.github.javaparser.printer.DefaultPrettyPrinter.print(DefaultPrettyPrinter.java:104)
at com.github.javaparser.ast.Node.toString(Node.java:320)
As it suggests that you can replace a 'Statement' with another statement so instead I tried another approach to replace the statement and with an 'Empty Statement'. It kind of worked for me but the output does not look good as it leaves extra ';' after the commented line.
At third I tried to go deeper and instead of replacing the statement I tried to replace the expression with an comment. That too failed as mentioned in SO - Javaparser comment expression.
Any idea how to fix this ?
I tried a workaround which does not feel like a good solution, but gives me the expected result for now:
BlockStmt blockStmt = (BlockStmt) expStmt.getParentNode().get();
blockStmt.getStatement(blockStmt.getStatements().indexOf(expStmt) + 1).setLineComment(expStmt.toString());
return null;
Related
The code below is action taken when a button is clicked on a simple form. The problem comes with the one if/else block. The If line is not terminated. The Else line is not terminated. But I have a consistent error that my Else exists without an If. I can't see why. I need someone smarter than me to identify what is going on here.
Thank you in advance!
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
FileFilter filter;
filter = new FileNameExtensionFilter("Comma Separated Value files","csv","txt");
JFileChooser chooser;
chooser = new JFileChooser();
chooser.addChoosableFileFilter(filter);
chooser.setFileSelectionMode(JFileChooser.FILES_ONLY);
int showDialog = chooser.showDialog(this, null);
File selectedFile = chooser.getSelectedFile();
String filename;
filename = selectedFile.getAbsolutePath();
if (filter.accept(selectedFile))
{
jTextField2.setText(filename);
jTextField2.setBackground(Color.white);
else
jTextField2.setText("You Did NOT Select a CSV File.");
jTextField2.setForeground(Color.black);
jTextField2.setBackground(Color.red);
}
}
You are missing the bracket '}' after "jTextField2.setBackground(Color.white);" and else.code is here
if (filter.accept(selectedFile))
{
jTextField2.setText(filename);
jTextField2.setBackground(Color.white);
}
else
{
jTextField2.setText("You Did NOT Select a CSV File.");
jTextField2.setForeground(Color.black);
jTextField2.setBackground(Color.red);
}
The SYNTAX for if-else Block looks like this:-
if {
// statements
} else {
//statements
}
Now if you are having only ONE statement inside the if Or else part then you can afford to skip the curly braces{ } otherwise you surely need to put those curly braces as compiler looks for it can terminate the execution of if statement.
However, it is always recommended to use the braces even if u have only ONE statement inside the if or else part as it improves the readability of the code.
You need to close your "if" and "else" blocks.
Example: if {} else {}.
if (filter.accept(selectedFile)) {
jTextField2.setText(filename);
jTextField2.setBackground(Color.white);
} else {
jTextField2.setText("You Did NOT Select a CSV File.");
jTextField2.setForeground(Color.black);
jTextField2.setBackground(Color.red);
}
The if's closing bracket is missing just before the else.
I'm having problems in understanding a part of the meaning of binding certain variable types in PDO and mysqli if the type given, in my case, seems to be meaningless. In the following code, the type bound (like i or s) gets ignored. The table row "wert_sortierung" in the database is INT(11). Regardingless if $val_int is really integer or not and if I bind it via i,s / PDO::PARAM_INT or _STR, the query always works, no break, no error or warning, that the types in the binding and database or variable itself don't fit.
<?
class PDOTest {
protected $pdo;
function __construct(){
$usr="usr";
$pwd="pwd";
$host="localhost";
$db="db";
$val_int="I'm a string";
$val_str="OP";
$querystring="SELECT wert_langtext FROM TB_wert WHERE wert_sortierung = ? AND wert_CD = ?";
try {
$db_info = "mysql:host=$host;dbname=$db"; // usually provided via require_once and during construction
$this->pdo = new PDO($db_info, $usr, $pwd);
$this->pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$this->pdo->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
$stmt = $this->pdo->prepare($querystring);
$stmt->bindValue(1,$val_int,PDO::PARAM_INT);
$stmt->bindValue(2,$val_str,PDO::PARAM_STR);
$stmt->execute();
$row_return = $stmt->fetchAll(PDO::FETCH_ASSOC);
$this->varprint($row_return);
$this->pdo = NULL;
}
catch (PDOException $ex) {
printf ('Es spricht:');
$this->printerror("Fehla! (" . $ex->getMessage() . ")");
$this->pdo = NULL;
exit();
}
printf("<br />-------<br />");
//Added for comparison
$mysqli = new mysqli($host, $usr, $pwd, $db);
$m_stmt = $mysqli->prepare($querystring);
$m_stmt->bind_param('is',$val_int, $val_str);
$m_stmt->execute();
$m_stmt->bind_result($row_return);
$m_stmt->fetch();
$this->varprint($row_return);
$m_stmt->close();
$mysqli->close();
}
private function printerror($txt) {
printf("<p><font color=\"#ff0000\">%s</font></p>\n",
htmlentities($txt));
}
private function varprint($var) {
echo "<br />";
echo "<pre>";
echo var_dump($var);
echo "</pre>";
}
}
new PDOTest();
?>
Please can anyone point out my error in reasoning.
It is actually Mysql's loose-typing that that deceived you.
As a matter of fact, regular Mysql queries can accept strings for the numberic values all right:
SELECT wert_langtext FROM TB_wert WHERE wert_sortierung = '1' AND wert_CD = '1';
while prepared statement just following this behavior.
However, a contrary situation is not that harmless. Addressing a string value with a number
SELECT wert_langtext FROM TB_wert WHERE wert_sortierung = 1;
will cause infinite number of warnings in case of wert_sortierung being of string type and some unexpected behavior, like matching for ALL the rows.
So, as a general advise I would suggest to always use 's' by default. The only drawback is PDO's emulated prepares and it can be easily worked around.
So, to answer your question explicitly - prepared statements just allow the same behavior as regular queries, adding nothing to it. Everything that possible with a regular query, is possible with prepared statement as well. And no, binding do not validate your data (however it should. Imn my class I test integer placeholders and throw an exception if no numeric value given)
I've noticed that when ordering by a datetime column in CI with active record, it's treating the column as a string, or int.
Example:
$this->db->limit(12);
$this->db->where('subscribed',1);
$this->db->join('profiles','profiles.user_id=users.id');
$this->db->where('active',1);
$this->db->select('users.thumbUpload,users.vanity_url');
$this->db->select('users.created_on as time');
$this->db->order_by('time');
$query = $this->db->get('users');
This is where users.created_on is a datetime field. Firstly, is it because active record is rendering time escaped, or is it something else? And if it is, can I prevent the escaping on order_by somehow?
Also, stackoverflow, please stop autocorrecting 'datetime' to 'date time'. It's annoying.
Cheers!
When you set second argument as false, function wont check and escape string. Try this
$this->db->select('users.created_on as time', FALSE);
Or for you query use
$this->db->order_by('users.created_on', 'DESC'); //or ASC
And for complex queries
$this->db->query("query");
According to the signature of the method in core files of CI (currently 2.2), it does not have any option to allow to choose whether or not to escape.
// The original prototype of the order_by()
public function order_by($orderby, $direction = '') {
// Definition
}
As you see there is not argument as $escape = true in the argument list. One way to do so is to hack this core file (I normally do not suggest it, since if you upgrade CI to a newer version later, then these changes will be lost, but if you do not intend to do so, it is OK to use it).
To do so, first change the prototype as:
public function order_by($orderby, $direction = '', $escape = true) {
// Definition
}
And then check the conditions in the following parts of definition:
// Line 842
if($escape){
$part = $this->_protect_identifiers(trim($part));
}else {
$part = trim($part);
}
// Line 856
if($escape){
$orderby = $this->_protect_identifiers($orderby);
}
When you call it, to prevent the escaping:
$this->db->order_by($ORDERBY_CLAUSE, null, false);
I know, poorly worded question not sure how else to ask though.
I always seem to end up in the error branch regardless of what i'm entering and can't figure out where i'm screwing this up. i'm using a particular flavor of Lex/YACC called GPPG which just sets this all up for use with C#
Here is my Y
method : L_METHOD L_VALUE ')' { System.Diagnostics.Debug.WriteLine("Found a method: Name:" + $1.Data ); }
| error { System.Diagnostics.Debug.WriteLine("Not valid in this statement context ");/*Throw new exception*/ }
;
here's my Lex
\'[^']*\' {this.yylval.Data = yytext.Replace("'",""); return (int)Tokens.L_VALUE;}
[a-zA-Z0-9]+\( {this.yylval.Data = yytext; return (int)Tokens.L_METHOD;}
The idea is that i should be able to pass
Method('value') to it and have it properly recognize that this is correct syntax
ultimately the plan is to execute the Method passing the various parameters as values
i've also tried several derivations. for example:
method : L_METHOD '(' L_VALUE ')' { System.Diagnostics.Debug.WriteLine("Found a method: Name:" + $1.Data ); }
| error { System.Diagnostics.Debug.WriteLine("Not valid in this statement context: ");/*Throw new exception*/ }
;
\'[^']*\' {this.yylval.Data = yytext.Replace("'",""); return (int)Tokens.L_VALUE;}
[a-zA-Z0-9]+ {this.yylval.Data = yytext; return (int)Tokens.L_METHOD;}
You need a lex rule to return the punctuation tokens 'as-is' so that the yacc grammar can recognize them. Something like:
[()] { return *yytext; }
added to your second example should do the trick.
I got this parameter:
$objDbCmd.Parameters.Add("#telephone", [System.Data.SqlDbType]::VarChar, 18) | Out-Null;
$objDbCmd.Parameters["#telephone"].Value = $objUser.Telephone;
Where the string $objUser.Telephone can be empty. If it's empty, how can I convert it to [DBNull]::Value?
I tried:
if ([string]:IsNullOrEmpty($objUser.Telephone)) { $objUser.Telephone = [DBNull]::Value };
But that gives me the error:
Exception calling "ExecuteNonQuery" with "0" argument(s): "Failed to convert parameter value from a ResultPropertyValueCollection to a String."
And if I convert it to a string, it inserts an empty string "", and not DBNull.
How can this be accomplished?
Thanks.
In PowerShell, you can treat null/empty strings as a boolean.
$x = $null
if ($x) { 'this wont print' }
$x = ""
if ($x) { 'this wont print' }
$x = "blah"
if ($x) { 'this will' }
So.... having said that you can do:
$Parameter.Value = $(if ($x) { $x } else { [DBNull]::Value })
But I'd much rather wrap this up in a function like:
function CatchNull([String]$x) {
if ($x) { $x } else { [DBNull]::Value }
}
I don't know about powershell, but in C# I would do something like this:
if ([string]::IsNullOrEmpty($objUser.Telephone))
{
$objDbCmd.Parameters["#telephone"].Value = [DBNull]::Value;
}
else
{
$objDbCmd.Parameters["#telephone"].Value = $objUser.Telephone;
}
Always append +"" at the end of db values...
$command.Parameters["#EmployeeType"].Value= $ADResult.EmployeeType + ""
Many years later, let me clarify:
Josh's answer shows a helpful simplification for testing strings for emptiness (relying on PowerShell's implicit to-Boolean conversion[1]), but it is unrelated to Tommy's (the OP's) problem.
Instead, the error message
"Failed to convert parameter value from a ResultPropertyValueCollection to a String."
implies that it is the non-null case that caused the problem, because $objDbCmd.Parameters["#telephone"].Value expects either a string value or [DBNull]::Value, whereas $objUser.Telephone is of type [ResultPropertyValueCollection], i.e. a collection of values.
Thus, in the non-null case, a string value must be assigned, which must be derived from the collection; one option is to take the first collection element's value, another would be to join all values with a separator to form a single string, using, e.g., [string]::Join(';', $objUser.Telephone) or, if joining the elements with spaces is acceptable (not a good idea with multiple phone numbers), simply with "$($objUser.Telephone)".[2]
Detecting an empty collection via [string]:IsNullOrEmpty() actually worked, despite the type mismatch, due to how PowerShell implicitly stringifies collections when passing a value to a [string] typed method parameter.[2]
Similarly, using implicit to-Boolean conversion works as expected with collections too: an empty collection evaluates to $false, a non-empty one to $true (as long as there are either at least two elements or the only element by itself would be considered $true[1])
Therefore, one solution is to use the first telephone number entry:
$objDbCmd.Parameters["#telephone"].Value = if ($objUser.Telephone) {
$objUser.Telephone[0].ToString() # use first entry
} else {
[DBNull]::Value
}
Note: If $objUser.Telephone[0] directly returns a [string], you can omit the .ToString() call.
In PowerShell v7+ you can alternatively shorten the statement via a ternary conditional:
$objDbCmd.Parameters["#telephone"].Value =
$objUser.Telephone ? $objUser.Telephone[0].ToString() : [DBNull]::Value
[1] For a comprehensive summary of PowerShell's automatic to-Boolean conversions, see the bottom section of this answer.
[2] When implicitly converting a collection to a string, PowerShell joins the stringified elements of a collection with a single space as the separator by default; you can override the separator with the automatic $OFS variable, but that is rarely done in practice; e.g., array 'foo', 'bar' is converted to 'foo bar'; note that this conversion does not apply when you call the collection's .ToString() method explicitly, but it does apply inside expandable (interpolating) strings, e.g., "$array".