Class VariableInput
- java.lang.Object
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- java.awt.Component
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- java.awt.TextComponent
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- java.awt.TextField
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- edu.hws.jcm.awt.VariableInput
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- All Implemented Interfaces:
InputObject
,Tieable
,Value
,java.awt.image.ImageObserver
,java.awt.MenuContainer
,java.io.Serializable
,javax.accessibility.Accessible
public class VariableInput extends java.awt.TextField implements InputObject, Tieable, Value
A VariableInput is an input box into which the user can type a real number value, which becomes the value of an associated Variable. The value of the Variable can change only when the VariableInput's checkInput() method is called (usually by a Controller). See the Controller class for more information.Whenever checkInput is called, an error of type JCMError might be generated. If throwErrors is true, this error is thrown; if it is false, the error is caught, the value of the variable is set to Double.NaN, and no error is thrown. The error message associated with the error can be retrieved by calling getErrorMessage(), if desired. (This value is null if no error occurred the last time checkInput was called.)
A VariableInput is a Value, so it can be used directly where a Value object is needed.
An VariableInput will ordinarily be registered with a Controller in TWO ways: It's added to a Controller with the Controller's add() method. This makes the Controller call the VariableInput's checkInput() method during the Controller's compute() method. Secondly, a Controller is set as the "onUserAction" property. This causes the Controller's compute() method to be called when the user presses return in the VariableInput box. This is optional-- you might, for example, only want the Controller to compute() when a Compute button is pressed. You can also set the VariableInput's onTextChange property to a Controller that you want to compute every time the text in the box changes.
After the VariableInput is created, it is possible to specify the largest and smallest allowed values for the variable. It is also possible to specify what sytle of input is allowed. The style can be to allow any constant expression, constant real numbers only, or integers only. Set these parameters with setMin(), setMax(), and setInputStyle(). For setInputStyle(), the legal parameter values are VariableInput.EXPRESSION, VariableInput.REAL, and VariableInput.INTEGER. The default input style is EXPRESSION.
- See Also:
- Serialized Form
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Field Summary
Fields Modifier and Type Field Description protected java.lang.String
errorMessage
Error message from the most recent time checkInput() as called.static int
EXPRESSION
A constant for use in the setInputStyle() method.protected int
inputStyle
One of the constant values EXPRESSION, REAL, or INTEGER, specifying the style of input.static int
INTEGER
A constant for use in the setInputStyle() method.protected double
maxValue
Largest allowable value.protected double
minValue
Smallest allowable value.protected java.lang.String
previousContents
This is set to true if the text in the box has been changed since the last time the value of the variable was checked by checkInput().static int
REAL
A constant for use in the setInputStyle() method.protected long
serialNumber
This serial number is increased each time the value of the variable changes.protected boolean
throwErrors
True if an error should be thrown when checkInput() is calles and the contents do not define a legal number.protected edu.hws.jcm.awt.VariableInput.VI
variable
The Variable that represents the value of this input box.
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Constructor Summary
Constructors Constructor Description VariableInput()
Create an unnamed VariableInput with initial contents "0".VariableInput(java.lang.String name, java.lang.String initialString)
Construct a VariableInput with the given name and initial String (which can both be null).VariableInput(java.lang.String name, java.lang.String initialString, Parser parser)
Create a VariableInput just as in the constructor VariableInput(String,String).
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
addTo(Parser p)
A convenience method that registers this VariableInput's variable with Parser p (but only if both p and the name of the variable are non-null).void
checkInput()
Check whether the contents are valid, and change the value of the associated variable if the new contents do not match the current value.protected double
convertInput(java.lang.String num)
Convert a string into a real value.java.lang.String
getErrorMessage()
Get error message from previous call to checkInput().int
getInputStyle()
Return the input style, which determines what types of things are allowed in the input box.double
getMax()
Return the maximum value that will be accepted in this VariableInput box.double
getMin()
Return the minimum value that will be accepted in this VariableInput box.Controller
getOnTextChange()
Return the Controller, if any, that is notified when the text in this input box changesController
getOnUserAction()
Return the Controller, if any, that is notified when the user presses return in this text-input box.long
getSerialNumber()
Return this object's serial number, which increases whenever the value of the associated variable changes.boolean
getThrowErrors()
Return the value of the throwErrors property.double
getVal()
Return the value of the associated variable, which might not reflect the value of the contents of the input box.Variable
getVariable()
Get the associated variable for the VariableInput box.void
notifyControllerOnChange(Controller c)
Method required by InputObject interface; in this class, it simply calls setOnUserAction(c).void
processActionEvent(java.awt.event.ActionEvent evt)
Overridden to call onUserAction.compute() if onUserAction is non-null.void
processTextEvent(java.awt.event.TextEvent evt)
Overridden to call onUserAction.compute() if onUserAction is non-null.void
setInputStyle(int style)
Specify what types of things are allowed in the input box.void
setMax(double max)
Specify the largest allowed value for the content of this VariableInput box.void
setMin(double min)
Specify the smallest allowed value for the content of this VariableInput box.void
setName(java.lang.String name)
Set the name of the variable.void
setOnTextChange(Controller c)
If the Controller, cm is non-null, then its compute() method will be called whenever the text in this input box changes.void
setOnUserAction(Controller c)
If the Controller, c, is non-null, then its compute() method will be called whenever the user presses the return key while typing in this text-input box.void
setText(java.lang.String text)
This overrides the setText() method from the TextField class so that it will also force the contents to be checked the next time the checkInput() method is called.void
setThrowErrors(boolean throwErrors)
Set the throwErrors property.void
setVal(double d)
Set the value of the associated variable.void
sync(Tie tie, Tieable newest)
Synchronize serial number and value with newest, unless this VariableInput is itself newest.JCMPanel
withLabel()
Convenience method for creating a component containing this VariableInput together with a label of the form "= ". JCMPanel
withLabel(java.awt.Color back, java.awt.Color fore)
Convenience method for creating a component containing this VariableInput together with a label of the form "name = ".-
Methods inherited from class java.awt.TextField
addActionListener, addNotify, echoCharIsSet, getAccessibleContext, getActionListeners, getColumns, getEchoChar, getListeners, getMinimumSize, getMinimumSize, getPreferredSize, getPreferredSize, minimumSize, minimumSize, paramString, preferredSize, preferredSize, processEvent, removeActionListener, setColumns, setEchoChar, setEchoCharacter
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Methods inherited from class java.awt.TextComponent
addTextListener, enableInputMethods, getBackground, getCaretPosition, getInputMethodRequests, getSelectedText, getSelectionEnd, getSelectionStart, getText, getTextListeners, isEditable, removeNotify, removeTextListener, select, selectAll, setBackground, setCaretPosition, setEditable, setSelectionEnd, setSelectionStart
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Methods inherited from class java.awt.Component
action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, createVolatileImage, createVolatileImage, deliverEvent, disable, disableEvents, dispatchEvent, doLayout, enable, enable, enableEvents, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getAlignmentX, getAlignmentY, getBaseline, getBaselineResizeBehavior, getBounds, getBounds, getColorModel, getComponentAt, getComponentAt, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeys, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphics, getGraphicsConfiguration, getHeight, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getKeyListeners, getLocale, getLocation, getLocation, getLocationOnScreen, getMaximumSize, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, invalidate, isBackgroundSet, isCursorSet, isDisplayable, isDoubleBuffered, isEnabled, isFocusable, isFocusCycleRoot, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isOpaque, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, layout, list, list, list, list, list, locate, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paint, paintAll, postEvent, prepareImage, prepareImage, print, printAll, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, requestFocus, requestFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, requestFocusInWindow, reshape, resize, resize, revalidate, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeys, setFocusTraversalKeysEnabled, setFont, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setMaximumSize, setMinimumSize, setMixingCutoutShape, setPreferredSize, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle, update, validate
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Field Detail
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variable
protected edu.hws.jcm.awt.VariableInput.VI variable
The Variable that represents the value of this input box. (VI is a private nested class inside VariableInput.)
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throwErrors
protected boolean throwErrors
True if an error should be thrown when checkInput() is calles and the contents do not define a legal number. True by default.
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errorMessage
protected java.lang.String errorMessage
Error message from the most recent time checkInput() as called. Null if there was no error.
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serialNumber
protected long serialNumber
This serial number is increased each time the value of the variable changes.
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previousContents
protected java.lang.String previousContents
This is set to true if the text in the box has been changed since the last time the value of the variable was checked by checkInput().
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minValue
protected double minValue
Smallest allowable value.
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maxValue
protected double maxValue
Largest allowable value.
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inputStyle
protected int inputStyle
One of the constant values EXPRESSION, REAL, or INTEGER, specifying the style of input.
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EXPRESSION
public static final int EXPRESSION
A constant for use in the setInputStyle() method. Any constant expression is allowed.- See Also:
- Constant Field Values
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REAL
public static final int REAL
A constant for use in the setInputStyle() method. Only real numbers are allowed.- See Also:
- Constant Field Values
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INTEGER
public static final int INTEGER
A constant for use in the setInputStyle() method. Only integers are allowed.- See Also:
- Constant Field Values
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Constructor Detail
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VariableInput
public VariableInput()
Create an unnamed VariableInput with initial contents "0".
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VariableInput
public VariableInput(java.lang.String name, java.lang.String initialString)
Construct a VariableInput with the given name and initial String (which can both be null). If initialString is null, the string "0" is used. No error occurs in the constructor if the initialString does not represent a legal value (A string rather than a double is used for initialization since the initial content can be an expression such as "pi/2".) If name is not null, it is used as the name of the VariableInput component as well as the name of the associated variable.
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VariableInput
public VariableInput(java.lang.String name, java.lang.String initialString, Parser parser)
Create a VariableInput just as in the constructor VariableInput(String,String). Then, if both parser and name are non-null, register the associated variable with the parser.
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Method Detail
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getVariable
public Variable getVariable()
Get the associated variable for the VariableInput box. You will need this, for example, if you want to register the variable with a Parser.
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withLabel
public JCMPanel withLabel()
Convenience method for creating a component containing this VariableInput together with a label of the form "= ". This version uses default colors for the label, which are inherited from the containing component.
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withLabel
public JCMPanel withLabel(java.awt.Color back, java.awt.Color fore)
Convenience method for creating a component containing this VariableInput together with a label of the form "name = ". Uses the given background and foreground colors for the label and the panel. The colors can be null to use the defaults, which will be inherited from the containing Component.
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setName
public void setName(java.lang.String name)
Set the name of the variable. This should not be called while the variable is registered with a Parser. The name of the VariableInput Component is also set to name, if the name is non=null.- Overrides:
setName
in classjava.awt.Component
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addTo
public void addTo(Parser p)
A convenience method that registers this VariableInput's variable with Parser p (but only if both p and the name of the variable are non-null).
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setOnUserAction
public void setOnUserAction(Controller c)
If the Controller, c, is non-null, then its compute() method will be called whenever the user presses the return key while typing in this text-input box.
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getOnUserAction
public Controller getOnUserAction()
Return the Controller, if any, that is notified when the user presses return in this text-input box.
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notifyControllerOnChange
public void notifyControllerOnChange(Controller c)
Method required by InputObject interface; in this class, it simply calls setOnUserAction(c). This is meant to be called by JCMPanel.gatherInputs().- Specified by:
notifyControllerOnChange
in interfaceInputObject
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setOnTextChange
public void setOnTextChange(Controller c)
If the Controller, cm is non-null, then its compute() method will be called whenever the text in this input box changes. Furthermore, the throwErrors property will be set to false, to avoid throwing multiple errors while the user is typing. (You can change it back to true if you want by calling setThrowErrors(true).)
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getOnTextChange
public Controller getOnTextChange()
Return the Controller, if any, that is notified when the text in this input box changes
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getVal
public double getVal()
Return the value of the associated variable, which might not reflect the value of the contents of the input box. The value of the variable changes only when the checkInput() method is called, or when the setVal() method is called. Call checkInput() first, if you want to be sure of getting the same value that is currently shown in the box.
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setVal
public void setVal(double d)
Set the value of the associated variable. Also sets the content of the input box.
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setThrowErrors
public void setThrowErrors(boolean throwErrors)
Set the throwErrors property. If the value is true, then an error will be thrown by the checkInput() method when the contents of the VariableInput box are not legal. Otherwise, no error is thrown; the value of the variable is just set to Double.NaN.
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getThrowErrors
public boolean getThrowErrors()
Return the value of the throwErrors property.
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setMin
public void setMin(double min)
Specify the smallest allowed value for the content of this VariableInput box.
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getMin
public double getMin()
Return the minimum value that will be accepted in this VariableInput box.
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setMax
public void setMax(double max)
Specify the largest allowed value for the content of this VariableInput box.
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getMax
public double getMax()
Return the maximum value that will be accepted in this VariableInput box.
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setInputStyle
public void setInputStyle(int style)
Specify what types of things are allowed in the input box. The value of the parameter, style, must be one of the constants VariableInput.EXPRESSION, VariableInput.REAL, or VariableInput.INTEGER. If not, the call to setInputStyle is ignored.
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getInputStyle
public int getInputStyle()
Return the input style, which determines what types of things are allowed in the input box. The returned value is one of the contstants EXPRESSION, REAL, or INTEGER
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getErrorMessage
public java.lang.String getErrorMessage()
Get error message from previous call to checkInput(). Returns null if there was no error.
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checkInput
public void checkInput()
Check whether the contents are valid, and change the value of the associated variable if the new contents do not match the current value. This might throw an error of type JCMError, if throwErrors is true. This is usually called by a Controller.- Specified by:
checkInput
in interfaceInputObject
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getSerialNumber
public long getSerialNumber()
Return this object's serial number, which increases whenever the value of the associated variable changes.- Specified by:
getSerialNumber
in interfaceTieable
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sync
public void sync(Tie tie, Tieable newest)
Synchronize serial number and value with newest, unless this VariableInput is itself newest. This is required by the Tieable interface, and is usually called by an object of type Tie.
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convertInput
protected double convertInput(java.lang.String num)
Convert a string into a real value. The parameter is taken from the input box when this method is called by VI.checkInput() Throw a JCMError if any error is found in the input.- Parameters:
num
- String to be converted- Returns:
- the real value.
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setText
public void setText(java.lang.String text)
This overrides the setText() method from the TextField class so that it will also force the contents to be checked the next time the checkInput() method is called.- Overrides:
setText
in classjava.awt.TextField
- Parameters:
text
- change text to this.
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processActionEvent
public void processActionEvent(java.awt.event.ActionEvent evt)
Overridden to call onUserAction.compute() if onUserAction is non-null. This is not meant to be called directly.- Overrides:
processActionEvent
in classjava.awt.TextField
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processTextEvent
public void processTextEvent(java.awt.event.TextEvent evt)
Overridden to call onUserAction.compute() if onUserAction is non-null. This is not meant to be called directly.- Overrides:
processTextEvent
in classjava.awt.TextComponent
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