It would be useful, if TextField/TextInputControl had some properties, which allow the developer to restrict the user input.

e.g. some useful properties would be:

maxLength (user cannot input more than X characters, as it exists in HTML).
restrict (as it exists in Flex: http://livedocs.adobe.com/flex/3/html/help.html?content=Working_with_Text_11.html )

Please also consider, that input can happen by context menu and CTRL+V, too (do not rely on KeyEvents).


Sample:


import javafx.beans.property.IntegerProperty;
import javafx.beans.property.SimpleIntegerProperty;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.scene.control.TextField;

/**
 * A text field, which restricts the user's input.
 */
public class AdvancedTextField extends TextField {

    private StringProperty restrict = new SimpleStringProperty();

    private IntegerProperty maxLength = new SimpleIntegerProperty(-1);

    public int getMaxLength() {
        return maxLength.get();
    }

    /**
     * Sets the max length of the text field.
     *
     * @param maxLength The max length.
     */
    public void setMaxLength(int maxLength) {
        this.maxLength.set(maxLength);
    }

    /**
     * Sets a regular expression character class which restricts the user input.<br/>
     * E.g. [0-9] only allows numeric values.
     *
     * @param restrict The regular expression.
     */
    public void setRestrict(String restrict) {
        this.restrict.set(restrict);
    }

    public String getRestrict() {
        return restrict.get();
    }

    public StringProperty restrictProperty() {
        return restrict;
    }

    public IntegerProperty maxLengthProperty() {
        return maxLength;
    }

    public AdvancedTextField() {

        textProperty().addListener(new ChangeListener<String>() {

            private boolean ignore;

            @Override
            public void changed(ObservableValue<? extends String> observableValue, String s, String s1) {
                if (ignore)
                    return;
                if (maxLength.get() > -1 && s1.length() > maxLength.get()) {
                    ignore = true;
                    setText(s1.substring(0, maxLength.get()));
                    ignore = false;
                }

                if (restrict.get() != null && !restrict.get().equals("") && !s1.matches(restrict.get() + "*")) {
                    ignore = true;
                    setText(s);
                    ignore = false;
                }
            }
        });
    }
}