The following pieces of source code come from our goodie JNumberField. It is a Java JTextField that only accepts
numeric values. This is a very usefull component as it means that within the software no checking of the validity
has to be performed when the String taken from the JTextField has to be converted into a number (a double).
Also it means that no error messages have to be constructed when the user erroneously types a text into a textfield
where only input of a number is meant.
Here are some pieces of the code :
package JosAertsBeans;
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.Toolkit.*;
public class JNumberField extends JTextField implements KeyListener, CaretListener, FocusListener {
/** Constructor with input for the length of the field. */
public JNumberField (int Columns) {
... }
/** Constructor without input. */
public JNumberField() {
... }
/** Handle the key typed event from the text field. */
public void keyTyped(KeyEvent evtKey) {
... }
/** Transform the contents of the field to a double */
public double getDoubleValue() {
... }
All comments that are included between /** and */ and immediately preceeding the constructor and method declarations
are automatically retrieved using the javadoc tool and put into an HTML file.
An additional advantage is that when a reusable component is used for which the source code is not available (think about purchased components), the API will always be available (the seller delivers the contract of the reusable compound), so that the developer can use the component without having to know or understand the actual implementation, and that also this piece of the application (although no source code) is well-documented.
The full HTML page (as automatically retrieved - no manual editing !) of our JNumberField goodie is given below:
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| SUMMARY: INNER | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD | ||||||
java.lang.Object
|
+--java.awt.Component
|
+--java.awt.Container
|
+--javax.swing.JComponent
|
+--javax.swing.text.JTextComponent
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+--javax.swing.JTextField
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+--JosAertsBeans.JNumberField
| Inner classes inherited from class javax.swing.JTextField |
javax.swing.JTextField.AccessibleJTextField |
| Inner classes inherited from class javax.swing.text.JTextComponent |
javax.swing.text.JTextComponent.AccessibleJTextComponent,
javax.swing.text.JTextComponent.KeyBinding |
| Inner classes inherited from class javax.swing.JComponent |
javax.swing.JComponent.AccessibleJComponent |
| Fields inherited from class javax.swing.JTextField |
notifyAction |
| Fields inherited from class javax.swing.text.JTextComponent |
DEFAULT_KEYMAP,
FOCUS_ACCELERATOR_KEY |
| Fields inherited from class javax.swing.JComponent |
accessibleContext,
listenerList,
TOOL_TIP_TEXT_KEY,
ui,
UNDEFINED_CONDITION,
WHEN_ANCESTOR_OF_FOCUSED_COMPONENT,
WHEN_FOCUSED,
WHEN_IN_FOCUSED_WINDOW |
| Fields inherited from class java.awt.Component |
BOTTOM_ALIGNMENT,
CENTER_ALIGNMENT,
LEFT_ALIGNMENT,
RIGHT_ALIGNMENT,
TOP_ALIGNMENT |
| Constructor Summary | |
JNumberField()
Constructor without input. |
|
JNumberField(int Columns)
Constructor with input for the length of the columns. |
|
| Method Summary | |
double |
atof(java.lang.String s)
Converts a string of digits to a double |
void |
caretUpdate(javax.swing.event.CaretEvent evtCaret)
Handle the caret update event from the text field. |
void |
errorInput(java.awt.event.KeyEvent evtKey)
Handle an invalid input and gives a beep |
void |
focusGained(java.awt.event.FocusEvent evtFocus)
Handle the focus Gained event from the text field. |
void |
focusLost(java.awt.event.FocusEvent evtFocus)
Handle the focus Lost event from the text field. |
double |
getDoubleValue()
Returns a double from the JNumberField |
boolean |
isFieldEmpty()
Checks whether the field is empty |
void |
keyPressed(java.awt.event.KeyEvent evtKey)
Handle the key pressed event from the text field. |
void |
keyReleased(java.awt.event.KeyEvent evtKey)
Handle the key released event from the text field. |
void |
keyTyped(java.awt.event.KeyEvent evtKey)
Handle the key typed event from the text field. |
void |
noValidField()
Method for an invalid field, gives a beep |
void |
resetParameters()
Reset all paramaters for validity checking |
| Methods inherited from class javax.swing.JTextField |
addActionListener,
createDefaultModel,
fireActionPerformed,
getAccessibleContext,
getActions,
getColumns,
getColumnWidth,
getHorizontalAlignment,
getHorizontalVisibility,
getPreferredSize,
getScrollOffset,
getUIClassID,
isValidateRoot,
paramString,
postActionEvent,
removeActionListener,
scrollRectToVisible,
setActionCommand,
setColumns,
setFont,
setHorizontalAlignment,
setScrollOffset |
| Methods inherited from class javax.swing.text.JTextComponent |
addCaretListener,
addKeymap,
copy,
cut,
fireCaretUpdate,
getCaret,
getCaretColor,
getCaretPosition,
getDisabledTextColor,
getDocument,
getFocusAccelerator,
getHighlighter,
getInputMethodRequests,
getKeymap,
getKeymap,
getMargin,
getPreferredScrollableViewportSize,
getScrollableBlockIncrement,
getScrollableTracksViewportHeight,
getScrollableTracksViewportWidth,
getScrollableUnitIncrement,
getSelectedText,
getSelectedTextColor,
getSelectionColor,
getSelectionEnd,
getSelectionStart,
getText,
getText,
getUI,
isEditable,
isFocusTraversable,
isOpaque,
loadKeymap,
modelToView,
moveCaretPosition,
paste,
processComponentKeyEvent,
processInputMethodEvent,
read,
removeCaretListener,
removeKeymap,
removeNotify,
replaceSelection,
select,
selectAll,
setCaret,
setCaretColor,
setCaretPosition,
setDisabledTextColor,
setDocument,
setEditable,
setEnabled,
setFocusAccelerator,
setHighlighter,
setKeymap,
setMargin,
setOpaque,
setSelectedTextColor,
setSelectionColor,
setSelectionEnd,
setSelectionStart,
setText,
setUI,
updateUI,
viewToModel,
write |
| Methods inherited from class javax.swing.JComponent |
addAncestorListener,
addNotify,
addPropertyChangeListener,
addVetoableChangeListener,
computeVisibleRect,
contains,
createToolTip,
firePropertyChange,
firePropertyChange,
firePropertyChange,
firePropertyChange,
firePropertyChange,
firePropertyChange,
firePropertyChange,
firePropertyChange,
firePropertyChange,
fireVetoableChange,
getActionForKeyStroke,
getAlignmentX,
getAlignmentY,
getAutoscrolls,
getBorder,
getBounds,
getClientProperty,
getComponentGraphics,
getConditionForKeyStroke,
getDebugGraphicsOptions,
getGraphics,
getHeight,
getInsets,
getInsets,
getLocation,
getMaximumSize,
getMinimumSize,
getNextFocusableComponent,
getRegisteredKeyStrokes,
getRootPane,
getSize,
getToolTipLocation,
getToolTipText,
getToolTipText,
getTopLevelAncestor,
getVisibleRect,
getWidth,
getX,
getY,
grabFocus,
hasFocus,
isDoubleBuffered,
isFocusCycleRoot,
isLightweightComponent,
isManagingFocus,
isOptimizedDrawingEnabled,
isPaintingTile,
isRequestFocusEnabled,
paint,
paintBorder,
paintChildren,
paintComponent,
paintImmediately,
paintImmediately,
processFocusEvent,
processKeyEvent,
processMouseMotionEvent,
putClientProperty,
registerKeyboardAction,
registerKeyboardAction,
removeAncestorListener,
removePropertyChangeListener,
removeVetoableChangeListener,
repaint,
repaint,
requestDefaultFocus,
requestFocus,
resetKeyboardActions,
reshape,
revalidate,
setAlignmentX,
setAlignmentY,
setAutoscrolls,
setBackground,
setBorder,
setDebugGraphicsOptions,
setDoubleBuffered,
setForeground,
setMaximumSize,
setMinimumSize,
setNextFocusableComponent,
setPreferredSize,
setRequestFocusEnabled,
setToolTipText,
setUI,
setVisible,
unregisterKeyboardAction,
update |
| Methods inherited from class java.awt.Container |
add,
add,
add,
add,
add,
addContainerListener,
addImpl,
countComponents,
deliverEvent,
doLayout,
findComponentAt,
findComponentAt,
getComponent,
getComponentAt,
getComponentAt,
getComponentCount,
getComponents,
getLayout,
insets,
invalidate,
isAncestorOf,
layout,
list,
list,
locate,
minimumSize,
paintComponents,
preferredSize,
print,
printComponents,
processContainerEvent,
processEvent,
remove,
remove,
removeAll,
removeContainerListener,
setLayout,
validate,
validateTree |
| Methods inherited from class java.awt.Component |
action,
add,
addComponentListener,
addFocusListener,
addInputMethodListener,
addKeyListener,
addMouseListener,
addMouseMotionListener,
addPropertyChangeListener,
bounds,
checkImage,
checkImage,
coalesceEvents,
contains,
createImage,
createImage,
disable,
disableEvents,
dispatchEvent,
enable,
enable,
enableEvents,
enableInputMethods,
getBackground,
getBounds,
getColorModel,
getComponentOrientation,
getCursor,
getDropTarget,
getFont,
getFontMetrics,
getForeground,
getInputContext,
getLocale,
getLocation,
getLocationOnScreen,
getName,
getParent,
getPeer,
getSize,
getToolkit,
getTreeLock,
gotFocus,
handleEvent,
hide,
imageUpdate,
inside,
isDisplayable,
isEnabled,
isLightweight,
isShowing,
isValid,
isVisible,
keyDown,
keyUp,
list,
list,
list,
location,
lostFocus,
mouseDown,
mouseDrag,
mouseEnter,
mouseExit,
mouseMove,
mouseUp,
move,
nextFocus,
paintAll,
postEvent,
prepareImage,
prepareImage,
printAll,
processComponentEvent,
processMouseEvent,
remove,
removeComponentListener,
removeFocusListener,
removeInputMethodListener,
removeKeyListener,
removeMouseListener,
removeMouseMotionListener,
removePropertyChangeListener,
repaint,
repaint,
repaint,
resize,
resize,
setBounds,
setBounds,
setComponentOrientation,
setCursor,
setDropTarget,
setLocale,
setLocation,
setLocation,
setName,
setSize,
setSize,
show,
show,
size,
toString,
transferFocus |
| Methods inherited from class java.lang.Object |
clone,
equals,
finalize,
getClass,
hashCode,
notify,
notifyAll,
wait,
wait,
wait |
| Constructor Detail |
public JNumberField(int Columns)
public JNumberField()
| Method Detail |
public void keyTyped(java.awt.event.KeyEvent evtKey)
public void keyPressed(java.awt.event.KeyEvent evtKey)
public void keyReleased(java.awt.event.KeyEvent evtKey)
public void caretUpdate(javax.swing.event.CaretEvent evtCaret)
public void focusGained(java.awt.event.FocusEvent evtFocus)
public void focusLost(java.awt.event.FocusEvent evtFocus)
public double getDoubleValue()
public double atof(java.lang.String s)
public boolean isFieldEmpty()
public void errorInput(java.awt.event.KeyEvent evtKey)
public void noValidField()
public void resetParameters()
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| SUMMARY: INNER | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD | ||||||