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Converting line and column coordinate to a caret position for a JSON debugger

I am building a small Java utility (using Jackson) to catch errors in Java files, and one part of it is a text area, in which you might paste some JSON context and it will tell you the line and column where it's found it:
I am using the error message to take out the line and column as a string and print it out in the interface for someone using it.
This is the JSON sample I'm working with, and there is an intentional error beside "age", where it's missing a colon:
{
"name": "mkyong.com",
"messages": ["msg 1", "msg 2", "msg 3"],
"age" 100
}
What I want to do is also highlight the problematic area in a cyan color, and for that purpose, I have this code for the button that validates what's inserted in the text area:
cmdValidate.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
functionsClass ops = new functionsClass();
String JSONcontent = JSONtextArea.getText();
Results obj = new Results();
ops.validate_JSON_text(JSONcontent, obj);
String result = obj.getResult();
String caret = obj.getCaret();
//String lineNum = obj.getLineNum();
//showStatus(result);
if(result==null) {
textAreaError.setText("JSON code is valid!");
} else {
textAreaError.setText(result);
Highlighter.HighlightPainter cyanPainter;
cyanPainter = new DefaultHighlighter.DefaultHighlightPainter(Color.cyan);
int caretPosition = Integer.parseInt(caret);
int lineNumber = 0;
try {
lineNumber = JSONtextArea.getLineOfOffset(caretPosition);
} catch (BadLocationException e2) {
// TODO Auto-generated catch block
e2.printStackTrace();
}
try {
JSONtextArea.getHighlighter().addHighlight(lineNumber, caretPosition + 1, cyanPainter);
} catch (BadLocationException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
}
});
}
The "addHighlight" method works with a start range, end range and a color, which didn't become apparent to me immediately, thinking I had to get the reference line based on the column number. Some split functions to extract the numbers, I assigned 11 (in screenshot) to a caret value, not realizing that it only counts character positions from the beginning of the string and represents the end point of the range.
For reference, this is the class that does the work behind the scenes, and the error handling at the bottom is about extracting the line and column numbers. For the record, "x" is the error message that would generate out of an invalid file.
package parsingJSON;
import java.io.IOException;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
public class functionsClass extends JSONTextCompare {
public boolean validate_JSON_text(String JSONcontent, Results obj) {
boolean valid = false;
try {
ObjectMapper objMapper = new ObjectMapper();
JsonNode validation = objMapper.readTree(JSONcontent);
valid = true;
}
catch (JsonParseException jpe){
String x = jpe.getMessage();
printTextArea(x, obj);
//return part_3;
}
catch (IOException ioe) {
String x = ioe.getMessage();
printTextArea(x, obj);
//return part_3;
}
return valid;
}
public void printTextArea(String x, Results obj) {
// TODO Auto-generated method stub
System.out.println(x);
String err = x.substring(x.lastIndexOf("\n"));
String parts[] = err.split(";");
//String part 1 is the discarded leading edge that is the closing brackets of the JSON content
String part_2 = parts[1];
//split again to get rid of the closing square bracket
String parts2[] = part_2.split("]");
String part_3 = parts2[0];
//JSONTextCompare feedback = new JSONTextCompare();
//split the output to get the exact location of the error to communicate back and highlight it in the JSONTextCompare class
//first need to get the line number from the output
String[] parts_lineNum = part_3.split("line: ");
String[] parts_lineNum_final = parts_lineNum[1].split(", column:");
String lineNum = parts_lineNum_final[0];
String[] parts_caret = part_3.split("column: ");
String caret = parts_caret[1];
System.out.println(caret);
obj.setLineNum(lineNum);
obj.setCaret(caret);
obj.setResult(part_3);
System.out.println(part_3);
}
}
Screenshot for what the interface currently looks like:
Long story short - how do I turn the coordinates Line 4, Col 11 into a caret value (e.g. it's value 189, for the sake of argument) that I can use to get the highlighter to work properly. Some kind of custom parsing formula might be possible, but in general, is that even possible to do?

how do I turn the coordinates Line 4, Col 11 into a caret value (e.g. it's value 189,
Check out: Text Utilities for methods that might be helpful when working with text components. It has methods like:
centerLineInScrollPane
getColumnAtCaret
getLineAtCaret
getLines
gotoStartOfLine
gotoFirstWordOnLine
getWrappedLines
In particular the gotoStartOfLine() method contains code you can modify to get the offset of the specified row/column.offset.
The basic code would be:
int line = 4;
int column = 11;
Element root = textArea.getDocument().getDefaultRootElement();
int offset = root.getElement( line - 1 ).getStartOffset() + column;
System.out.println(offset);

The way it works is essentially counting the number of characters in each line, up until the line in which the error is occurring, and adding the caretPosition to that sum of characters, which is what the Highlighter needs to apply the marking to the correct location.
I've added the code for the Validate button for context.
functionsClass ops = new functionsClass();
String JSONcontent = JSONtextArea.getText();
Results obj = new Results();
ops.validate_JSON_text(JSONcontent, obj);
String result = obj.getResult();
String caret = obj.getCaret();
String lineNum = obj.getLineNum();
//showStatus(result);
if(result==null) {
textAreaError.setText("JSON code is valid!");
} else {
textAreaError.setText(result);
Highlighter.HighlightPainter cyanPainter;
cyanPainter = new DefaultHighlighter.DefaultHighlightPainter(Color.cyan);
//the column number as per the location of the error
int caretPosition = Integer.parseInt(caret); //JSONtextArea.getCaretPosition();
//the line number as per the location of the error
int lineNumber = Integer.parseInt(lineNum);
//get the number of characters in the string up to the line in which the error is found
int totalChars = 0;
int counter = 0; //used to only go to the line above where the error is located
String[] lines = JSONcontent.split("\\r?\\n");
for (String line : lines) {
counter = counter + 1;
//as long as we're above the line of the error (lineNumber variable), keep counting characters
if (counter < lineNumber)
{
totalChars = totalChars + line.length();
}
//if we are at the line that contains the error, only add the caretPosition value to get the final position where the highlighting should go
if (counter == lineNumber)
{
totalChars = totalChars + caretPosition;
break;
}
}
//put down the highlighting in the area where the JSON file is having a problem
try {
JSONtextArea.getHighlighter().addHighlight(totalChars - 2, totalChars + 2, cyanPainter);
} catch (BadLocationException e1) {
// TODO Auto-generated catch block
e1.getMessage();
}
}
The contents of the JSON file is treated as a string, and that's why I'm also iterating through it in that fashion. There are certainly better ways to go through lines in the string, and I'll add some reference topics on SO:
What is the easiest/best/most correct way to iterate through the characters of a string in Java? - Link
Check if a string contains \n - Link
Split Java String by New Line - Link
What is the best way to iterate over the lines of a Java String? - Link
Generally a combination of these led to this solution, and I am also not targeting it for use on very large JSON files.
A screenshot of the output, with the interface highlighting the same area that Notepad++ would complain about, if it could debug code:
I'll post the project on GitHub after I clean it up and comment it some, and will give a link to that later, but for now, hopefully this helps the next dev in a similar situation.

Java SQL problem executing query through CallableStatement with parameter

I have a problem in a CallableStatement that execute a stored procedure query which accept a parameter.
I have a list of string that contains the query like:
{call query5_immatricolati(?)}
I have a list of string that contains the parameter like
String cds = "L-INF";
I have no SQL syntax error when I run but the result set doesn't have any value.
The expected result of the execution is that i could create an object by receiving data from the result set.
Here is the code:
for (int i = 0; i < INDICATORI.getInstance().getListaIndicatori().size();) {
for (int j = 0; j < INDICATORI.getInstance().getListaQuery().size();) {
if (INDICATORI.getInstance().getListaIndicatori().get(i).equals("iC00a")) {
for (String cds : CDS.getInstance().getCds().values()) {
ArrayList<indicatore> lista = new ArrayList<indicatore>();
String query = INDICATORI.getInstance().getListaQuery().get(j);
try {
CallableStatement cb = DB.getInstance().getConnection().prepareCall(query);
cb.setString(1, cds);
DB.getInstance().setResultSet(cb.executeQuery());
} catch (SQLException e) {
e.printStackTrace();
}
try {
while (DB.getInstance().getResultSet().next()) {
iC00a obj = new iC00a();
obj.setId(counter);
obj.setAnnoIscrizione(DB.getInstance().getResultSet().getString(1));
obj.setIscrittiPrimoAnno(DB.getInstance().getResultSet().getInt(2));
lista.add(obj);
counter++;
}
} catch (SQLException e) {
e.printStackTrace();
}
map.getInstance().getMap().put(INDICATORI.getInstance().getListaIndicatori().get(i)+cds, lista);
counter=0;
}
}
i++;
j++;
}
}
I tried to manually set in cb.setString(1,cds) the value like cb.setString(1,"L-INF") AND IT WORKS !!!
But I can't set manually the parameter, I need to iterate with for each loop each string and dynamically insert as parameter.
Why if I set the parameter manually like a string it works instead if i give a string variable not ?
Could anyone tell me what I'm doing wrong?

After a lot of attempts, I've found the solution.
The problem is in your variable cdsbecause it could have white spaces before or after.
Try:
cb.setString(1,cds.strip());
For me it worked.

LensKit: LensKit demo is not reading my data file

When I run the LensKit demo program I get this error:
[main] ERROR org.grouplens.lenskit.data.dao.DelimitedTextRatingCursor - C:\Users\sean\Desktop\ml-100k\u - Copy.data:4: invalid input, skipping line
I reworked the ML 100k data set so that it only holds this line although I dont see how this would effect it:
196 242 3 881250949
186 302 3 891717742
22 377 1 878887116
244
Here is the code I am using too:
public class HelloLenskit implements Runnable {
public static void main(String[] args) {
HelloLenskit hello = new HelloLenskit(args);
try {
hello.run();
} catch (RuntimeException e) {
System.err.println(e.getMessage());
System.exit(1);
}
}
private String delimiter = "\t";
private File inputFile = new File("C:\\Users\\sean\\Desktop\\ml-100k\\u - Copy.data");
private List<Long> users;
public HelloLenskit(String[] args) {
int nextArg = 0;
boolean done = false;
while (!done && nextArg < args.length) {
String arg = args[nextArg];
if (arg.equals("-e")) {
delimiter = args[nextArg + 1];
nextArg += 2;
} else if (arg.startsWith("-")) {
throw new RuntimeException("unknown option: " + arg);
} else {
inputFile = new File(arg);
nextArg += 1;
done = true;
}
}
users = new ArrayList<Long>(args.length - nextArg);
for (; nextArg < args.length; nextArg++) {
users.add(Long.parseLong(args[nextArg]));
}
}
public void run() {
// We first need to configure the data access.
// We will use a simple delimited file; you can use something else like
// a database (see JDBCRatingDAO).
EventDAO base = new SimpleFileRatingDAO(inputFile, "\t");
// Reading directly from CSV files is slow, so we'll cache it in memory.
// You can use SoftFactory here to allow ratings to be expunged and re-read
// as memory limits demand. If you're using a database, just use it directly.
EventDAO dao = new EventCollectionDAO(Cursors.makeList(base.streamEvents()));
// Second step is to create the LensKit configuration...
LenskitConfiguration config = new LenskitConfiguration();
// ... configure the data source
config.bind(EventDAO.class).to(dao);
// ... and configure the item scorer. The bind and set methods
// are what you use to do that. Here, we want an item-item scorer.
config.bind(ItemScorer.class)
.to(ItemItemScorer.class);
// let's use personalized mean rating as the baseline/fallback predictor.
// 2-step process:
// First, use the user mean rating as the baseline scorer
config.bind(BaselineScorer.class, ItemScorer.class)
.to(UserMeanItemScorer.class);
// Second, use the item mean rating as the base for user means
config.bind(UserMeanBaseline.class, ItemScorer.class)
.to(ItemMeanRatingItemScorer.class);
// and normalize ratings by baseline prior to computing similarities
config.bind(UserVectorNormalizer.class)
.to(BaselineSubtractingUserVectorNormalizer.class);
// There are more parameters, roles, and components that can be set. See the
// JavaDoc for each recommender algorithm for more information.
// Now that we have a factory, build a recommender from the configuration
// and data source. This will compute the similarity matrix and return a recommender
// that uses it.
Recommender rec = null;
try {
rec = LenskitRecommender.build(config);
} catch (RecommenderBuildException e) {
throw new RuntimeException("recommender build failed", e);
}
// we want to recommend items
ItemRecommender irec = rec.getItemRecommender();
assert irec != null; // not null because we configured one
// for users
for (long user: users) {
// get 10 recommendation for the user
List<ScoredId> recs = irec.recommend(user, 10);
System.out.format("Recommendations for %d:\n", user);
for (ScoredId item: recs) {
System.out.format("\t%d\n", item.getId());
}
}
}
}
I am really lost on this one and would appreciate any help. Thanks for your time.

The last line of your input file only contains one field. Each input file line needs to contain 3 or 4 fields.

Mysql: Get Strings?

I try to receive all names out of my database.
I did write this code:
public static String getCmdCommand(int resultCount) throws Exception {
try {
// This will load the MySQL driver, each DB has its own driver
Class.forName("com.mysql.jdbc.Driver");
// Setup the connection with the DB
connect = DriverManager.getConnection(""+MyBot.mysqlDbPath+"",""+MyBot.mysqlDbUsername+"",""+MyBot.mysqlDbPassword+"");
PreparedStatement zpst=null;
ResultSet zrs=null;
zpst=connect.prepareStatement("SELECT `befehlsname` FROM `eigenebenutzerbefehle`");
zrs=zpst.executeQuery();
if(zrs.next()){
return zrs.getString(resultCount);
}else{
return "-none-";
}
}catch (Exception e) {
throw e;
} finally {
close();
}
}
and i start the method by running a loop:
for(int i = 0; i <= cmdAmount-1; i++){
try {
eebBenutzerBefehl = dao.getCmdCommand(i);
} catch (Exception e) {
e.printStackTrace();
}
}
cmdAmount is a integer with the valuable of the total fields inside the database.
so i.e My database holds name1 name2 name3, is it wrong to call them like this? :
return zrs.getString(resultCount);
which should be:
zrs.getString(0) = name1
zrs.getString(1) = name2
zrs.getString(2) = name3
I always receive java.sql.SQLException: Column Index out of range, perhaps it just continue to check the first entry only in the database :confused:

return zrs.getString(resultCount);
The getString() method should be given the index of the column you want to return which is always going to be the same. You should pass in a constant here such as 0.
Also, you should open the database only once rather than over and over again in that one method by passing in the "connect" variable as a parameter.
Here's what I would do if you are wanting to retrieve the name from each row of the table.
public static ArrayList<String> getCmdCommand(Connection connect) throws Exception {
try {
PreparedStatement zpst=null;
ResultSet zrs=null;
ArrayList<String> names = new ArrayList<String>();
zpst=connect.prepareStatement("SELECT `befehlsname` FROM `eigenebenutzerbefehle`");
zrs=zpst.executeQuery();
// The result set contains all the names retrieved from the call to the database, so
// you just need to iterate through them all and store them in a list.
while(zrs.next()) {
names.add(zrs.getString(0));
}
} catch (Exception e) {
throw e;
} finally {
close();
}
return names;
}
You don't need to tell it how many fields there are because it will figure that out itself.
Class.forName("com.mysql.jdbc.Driver");
Connection connect = DriverManager.getConnection(""+MyBot.mysqlDbPath+"",""+MyBot.mysqlDbUsername+"",""+MyBot.mysqlDbPassword+"");
try {
ArrayList<String> names = dao.getCmdCommand(connect);
} catch (Exception e) {
e.printStackTrace();
}
if(names.size() < 1) {
// " - none - "
}

Better handling of number format exception in android

I've got the following code snippet that I'm thinking of refactoring to a more abstract application exception handler but I want to make sure I've got it as tidy as possible first
Any suggestions on how to improve this code or make it more resuable
int id = -1;
final StringBuilder errorMessage = new StringBuilder("Bad Input Value: ");
try {
id = Integer.parseInt(edtId.getText().toString());
} catch (final NumberFormatException e) {
errorMessage.append("Failed to parse id " + e.getMessage());
}
if (id < 0) {
errorToast(errorMessage.toString());
} else {
//go ahead an retreive values from database knowing the id has been parsed
//correctly to a positive int.
}

Why pre-assign id to a magic number?
try {
int id=Integer.parseInt(edtId.getText().toString());
//go on as normal
} catch (NumberFormatException e) {
//handle error
}