Cannot understand ComboBoxTableCell in a TableView - javafx-8

Question

I have read everything available on this site and others; I have cut and pasted every line of code ever written on this subject ( am willing to bet). This is what the result is:
final class Books extends Group {
private TableView table = new TableView();
private ObservableList<Book> data = FXCollections.observableArrayList();
final HBox hb = new HBox();
final TextField Title = new TextField();
final TextField Author = new TextField();
final TextField Publisher = new TextField();
final TextField Copywrite = new TextField();
final TextField ISBN = new TextField();
final Boolean CheckedOut = false;
final Label Whom;
final Button addButton = new Button("Add");
Boolean FirstRead = true;
public static class Book {
private final SimpleStringProperty title;
private final SimpleStringProperty author;
private final SimpleStringProperty publisher;
private final SimpleStringProperty copywrite;
private final SimpleStringProperty isbn;
private final BooleanProperty checkedout;
private final SimpleStringProperty who;
Book(String Titl, String Auth, String Publ,
String Cpywrit, String IsBn, Boolean ChkdOut, String WHO) {
this.title = new SimpleStringProperty(Titl);
this.author = new SimpleStringProperty(Auth);
this.publisher = new SimpleStringProperty(Publ);
this.copywrite = new SimpleStringProperty(Cpywrit);
this.isbn = new SimpleStringProperty(IsBn);
this.checkedout = new SimpleBooleanProperty(ChkdOut);
this.who = new SimpleStringProperty(WHO);
}
public boolean isCheckedOut() {
return checkedout.get();
}
public void setCheckedOut(boolean international) {
this.checkedout.set(international);
}
public BooleanProperty isCheckedOutProperty() {
return checkedout;
}
public String getTitle() {
return title.get();
}
public void setTitle(String Title) {
title.set(Title);
}
public String getAuthor() {
return author.get();
}
public void setAutor(String Author) {
author.set(Author);
}
public String getPublisher() {
return publisher.get();
}
public void setPublisher(String Publisher) {
publisher.set(Publisher);
}
public String getCopywrite() {
return copywrite.get();
}
public void setCopywrite(String Copywrite) {
copywrite.set(Copywrite);
}
public String getIsbn() {
return isbn.get();
}
public void setIsbn(String ISBN) {
isbn.set(ISBN);
}
public Boolean getIo() {
return checkedout.get();
}
public void setIo(Boolean CheckedOut) {
checkedout.set(CheckedOut);
}
public String getWho() {
return who.get();
}
public void setWho(String Who) {
who.set(Who);
}
public ObservableValue<String> whoProperty() {
return who;
}
}
public Books(final File User) throws IOException {
this.Whom = new Label("inLibrary");
this.data = FXCollections.<Book>observableArrayList(
(Book bk) -> new Observable[]{bk.isCheckedOutProperty()
});
final PhoneList p = new PhoneList(User);
final Label label = new Label("Book List");
label.setFont(new Font("Arial", 20));
table.setPrefSize(600, 400);
table.setEditable(true);
TableColumn nameCol = bookName();
TableColumn authorCol = bookAuthor();
TableColumn publisherCol = bookPublisher();
TableColumn copywriteCol = bookCopywrite();
TableColumn isbnCol = bookISBN();
final TableColumn<Book, Boolean> ioCol = new TableColumn<>("In/Out");
ioCol.setMinWidth(50);
ioCol.setEditable(true);
ioCol.setCellValueFactory(new PropertyValueFactory<>("isCheckedOut"));
final Callback<TableColumn<Book, Boolean>, TableCell<Book, Boolean>> iocellFactory = CheckBoxTableCell.forTableColumn(ioCol);
ioCol.setCellFactory((TableColumn<Book, Boolean> column) -> {
TableCell<Book, Boolean> iocell = iocellFactory.call(column);
iocell.setAlignment(Pos.CENTER);
return iocell;
});
ioCol.setCellFactory(iocellFactor
final TableColumn<String, Book> whoCol = new TableColumn<>("Who to");
whoCol.setMinWidth(100);
whoCol.setEditable(true);
whoCol.setCellValueFactory(new PropertyValueFactory<>("who"));
whoCol.setCellFactory(ComboBoxTableCell.forTableColumn(new StringConverter<Book>() {
#Override
public String toString(Book string) {
return string.getWho();
}
#Override
public Book fromString(String string) {
return null;
}
}, data));
AddBook(nameCol, authorCol, publisherCol, copywriteCol, isbnCol, ioCol, whoCol, User);
data.addListener((javafx.collections.ListChangeListener.Change<? extends Book> change) -> {
while (change.next()) {
if (change.wasUpdated() && FirstRead != true) {
try {
System.out.println("List changed");
writeFile(User);
} catch (IOException ex) {
Logger.getLogger(Books.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
});
final VBox vbox = new VBox();
vbox.setSpacing(5);
vbox.setPadding(new Insets(10, 0, 0, 10));
vbox.getChildren().addAll(label, table, hb);
getChildren().addAll(vbox);
try {
readFile(User);
} catch (Exception ex) {
Logger.getLogger(Books.class.getName()).log(Level.SEVERE, null, ex);
}
}
private TableColumn bookISBN() {
TableColumn isbnCol = new TableColumn("ISBN #");
isbnCol.setMinWidth(100);
isbnCol.setCellValueFactory(
new PropertyValueFactory<>("isbn"));
isbnCol.setCellFactory(TextFieldTableCell.forTableColumn());
return isbnCol;
}
private TableColumn bookCopywrite() {
TableColumn copywriteCol = new TableColumn("Copywrite");
copywriteCol.setMinWidth(100);
copywriteCol.setCellValueFactory(
new PropertyValueFactory<>("copywrite"));
copywriteCol.setCellFactory(TextFieldTableCell.forTableColumn());
return copywriteCol;
}
private TableColumn bookPublisher() {
TableColumn publisherCol = new TableColumn("Publisher");
publisherCol.setMinWidth(100);
publisherCol.setCellValueFactory(
new PropertyValueFactory<>("publisher"));
publisherCol.setCellFactory(TextFieldTableCell.forTableColumn());
return publisherCol;
}
private TableColumn bookAuthor() {
TableColumn authorCol = new TableColumn("Author");
authorCol.setMinWidth(100);
authorCol.setCellValueFactory(
new PropertyValueFactory<>("author"));
authorCol.setCellFactory(TextFieldTableCell.forTableColumn());
return authorCol;
}
private TableColumn bookName() {
TableColumn nameCol = new TableColumn("Title");
nameCol.setMaxWidth(100);
nameCol.setCellValueFactory(
new PropertyValueFactory<>("title"));
nameCol.setCellFactory(TextFieldTableCell.forTableColumn());
return nameCol;
}
private void AddBook(TableColumn nameCol, TableColumn authorCol, TableColumn publisherCol,
TableColumn copywriteCol, TableColumn isbnCol, TableColumn ioCol, TableColumn whoCol, final File User) {
table.setItems(data);
table.getColumns().addAll(nameCol, authorCol, publisherCol, copywriteCol, isbnCol, ioCol, whoCol);
addButton.setOnAction(
new EventHandler<ActionEvent>() {
#Override
public void handle(ActionEvent e) {
addBook();
try {
writeFile(User);
} catch (IOException ex) {
Logger.getLogger(Books.class.getName()).log(Level.SEVERE, null, ex);
}
}
private void addBook() {
data.add(new Book(
Title.getText(),
Author.getText(),
Publisher.getText(),
Copywrite.getText(),
ISBN.getText(),
CheckedOut,
Whom.getText()
));
Title.clear();
Author.clear();
Publisher.clear();
Copywrite.clear();
ISBN.clear();
}
});
hb.getChildren().addAll(Title, Author, Publisher,
Copywrite, ISBN, addButton);
hb.setSpacing(10);
Title.setPromptText("Tile of Book");
Title.setMaxWidth(nameCol.getPrefWidth());
Author.setMaxWidth(authorCol.getPrefWidth());
Author.setPromptText("Author");
Publisher.setMaxWidth(publisherCol.getPrefWidth());
Publisher.setPromptText("Publisher");
Copywrite.setMaxWidth(copywriteCol.getPrefWidth());
Copywrite.setPromptText("Year Copywrite");
ISBN.setMaxWidth(isbnCol.getPrefWidth());
ISBN.setPromptText("ISBN #");
}
private void writeFile(File User) throws IOException {
File file = new File(User + "/Books.txt");
FileWriter fw = new FileWriter(file);
BufferedWriter bw = new BufferedWriter(fw);
PrintWriter outFile = new PrintWriter(bw);
if (table.getItems() != null) {
data.stream().map((data1) -> {
if (data1.getTitle().equals("")) {
data1.setTitle("No_Title");
}
return data1;
}).map((data1) -> {
if (data1.getAuthor().equals("")) {
data1.setAutor("No_Author");
}
return data1;
}).map((data1) -> {
if (data1.getPublisher().equals("")) {
data1.setPublisher("No_Publisher");
}
return data1;
}).map((data1) -> {
if (data1.getCopywrite().equals("")) {
data1.setCopywrite("No_Copywrite");
}
return data1;
}).map((data1) -> {
if (data1.getIsbn().equals("")) {
data1.setIsbn("No_ISBN");
}
return data1;
}).map((data1) -> {
if (data1.getWho().equals("")) {
data1.setWho("InLibrary");
}
return data1;
}).map((data1) -> {
outFile.println(data1.getTitle());
return data1;
}).map((data1) -> {
outFile.println(data1.getAuthor());
return data1;
}).map((data1) -> {
outFile.println(data1.getPublisher());
return data1;
}).map((data1) -> {
outFile.println(data1.getCopywrite());
return data1;
}).map((data1) -> {
outFile.println(data1.getIsbn());
return data1;
}).map((data1) -> {
outFile.println(data1.getIo());
return data1;
}).forEach((data1) -> {
outFile.println(data1.getWho());
});
outFile.close();
}
}
private void readFile(File User) throws Exception {
try {
String name, author, publisher, copywrite, isbn, whom;
Boolean InOut;
try (Scanner inFile = new Scanner(new File(User + "/Books.txt"))) {
while (inFile.hasNextLine()) {
name = inFile.next();
author = inFile.next();
publisher = inFile.next();
copywrite = inFile.next();
isbn = inFile.next();
InOut = inFile.nextBoolean();
whom = inFile.next();
data.add(new Book(name, author, publisher, copywrite,
isbn, InOut, whom));
}
}
table.setItems(data);
} //insert catch statements
catch (FileNotFoundException exception) {
System.out.println("File not found");
} catch (ArrayIndexOutOfBoundsException AIOOBexception) {
System.out.println("Array Index is out of bounds");
} catch (IllegalArgumentException IAexception) {
System.out.println("Divide by zero error");
} catch (NoSuchElementException NAexception) {
}
FirstRead = false;
}
}
This gives the following error:
Exception in thread "JavaFX Application Thread" java.lang.ClassCastException: mediatracker.Books$Book cannot be cast to java.lang.String
at mediatracker.Books$1.toString(Books.java:198)
Line 198 starts:
whoCol.setCellFactory(ComboBoxTableCell.forTableColumn(new StringConverter<Book>() {
Can anyone type in the "theory" behind the ComboBoxTableCell, and list the parts necessary to accomoplish this. All I want to do is to change the value of the cell extracted from a PhoneList in another file.

Answer 1

I'm just going to assume that line 198 is
return (String) object ;
in the anonymous StringConverter's toString() method. When you post a question with a stack trace, always indicate which is the line in your code to which the exception is pointing.
First, it's always better to use generic types instead of raw types. So instead of
TableColumn whoCol = ...
you should have
TableColumn<S,T> whoCol = ...
where you replace S with the type of the data in the table and T with the type of the data in the column. Since you haven't given a complete example, I have no way of guessing what S is; from the error message it looks like the type of the data in the column might be Book.
Read the Javadocs for the method you are calling. They clearly state what the converter is:
converter - A StringConverter to convert the given item (of type T) to
a String for displaying to the user.
So, assuming that your TableColumn is displaying Books, and assuming data is of type ObservableList<Book>, you should have something like
ObservableList<Book> data = ... ;
TableColumn<S, Book> whoCol = new TableColumn<>("Who to");
// ...
whoCol.setCellFactory(ComboBoxTableCell.forTableColumn(new StringConverter<Book>() {
#Override
public String toString(Book book) {
// assuming your Book class defines a getTitle() method, and that's
// how you want to display it in your ComboBox:
return book.getTitle(); // or get a String from book some other way
}
#Override
public Book fromString(String string) {
// I think this is not actually used, as the combo box is not editable
// So you could probably safely just return null here.
// But in general:
Book book = ... ; // create a book from the string
return book ;
}
}, data));
Again, you replace S by whatever you are using for the type of the TableView; and again I had to make guesses at the type of your TableColumn as you didn't provide a complete example. But this should be enough for you to get the idea.

Answer 2

`final TableColumn<Book, String> whoCol = new TableColumn<>("Who to");
whoCol.setMinWidth(100);
whoCol.setEditable(true);
whoCol.setCellValueFactory(new PropertyValueFactory<>("who"));
whoCol.setCellFactory(ComboBoxTableCell.<Book, String>forTableColumn(p.data.get(myIndex()).toString()));
whoCol.setOnEditCommit((TableColumn.CellEditEvent<Book, String> t) -> {
((Book) t.getTableView().getItems().get(
t.getTablePosition().getRow()))
.setWho(t.getNewValue());
try {
writeFile(User);
} catch (IOException ex) {
Logger.getLogger(Books.class.getName()).log(Level.SEVERE, null, ex);
}
});`
This works - #James_D thank you for your aid - you sent me in the right direction

Answer 3

Your problems don't seem to have anything to do with a ComboBoxTableCell.
Your toString() method is wrong; you're trying to cast an Object to a String. That's (probably) why you're seeing a java.lang.ClassCastException. Can you verify which line is line 198?
Also, I notice all your fromString() method does is return its argument. What exactly are you trying to achieve here in this code snippet? Can you give us a little more background information?