GObject (acm 2.1 API)

java.lang.Object
- acm.graphics.GObject

All Implemented Interfaces:

java.lang.Cloneable

Direct Known Subclasses:

GArc, GCompound, GImage, GLabel, GLine, GOval, GPen, GPolygon, GRect, GTurtle
```
public abstract class GObject
extends java.lang.Object
implements java.lang.Cloneable
```
This class is the common superclass of all graphical objects that can be displayed on a GCanvas. Because it is an abstract class, you are not allowed to construct an object whose class is GObject directly. What you do instead is construct one of the concrete subclasses like GRect or GLine. The purpose of this class definition is to define methods that apply to all graphical objects regardless of their specific class.

Constructor Summary

Constructors
Modifier Constructor and Description

protected GObject()
Constructs a new GObject and initializes its state.

Constructors
Modifier	Constructor and Description
`protected`	`GObject()` Constructs a new `GObject` and initializes its state.

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addActionListener(java.awt.event.ActionListener listener)` Adds an action listener to this graphical object.
`void`	`addMouseListener(java.awt.event.MouseListener listener)` Adds a mouse listener to this graphical object.
`void`	`addMouseMotionListener(java.awt.event.MouseMotionListener listener)` Adds a mouse motion listener to this graphical object.
`protected boolean`	`areMouseListenersEnabled()` Returns `true` if mouse listeners have ever been assigned to this object.
`protected static java.lang.String`	`colorName(java.awt.Color color)` Translates a color to a string representation.
`boolean`	`contains(double x, double y)` Checks to see whether a point is inside the object.
`boolean`	`contains(GPoint pt)` Checks to see whether a point is inside the object.
`void`	`fireActionEvent(java.awt.event.ActionEvent e)` Triggers an action event for this graphical object.
`void`	`fireActionEvent(java.lang.String actionCommand)` Triggers an action event for this graphical object with the specified action command.
`protected void`	`fireMouseListeners(java.awt.event.MouseEvent e)` Sends the event to the appropriate listener.
`abstract GRectangle`	`getBounds()` Returns the bounding box of this object, which is defined to be the smallest rectangle that covers everything drawn by the figure.
`java.awt.Color`	`getColor()` Returns the color used to display this object.
`protected java.awt.Component`	`getComponent()` Returns the component in which this object is installed, or `null` if none exists.
`double`	`getHeight()` Returns the height of this object, which is defined to be the height of the bounding box.
`GPoint`	`getLocation()` Returns the location of this object as a `GPoint`.
`protected java.awt.Color`	`getObjectColor()` This method returns the color set for this specific object, which may be `null`.
`GContainer`	`getParent()` Returns the parent of this object, which is the canvas or compound object in which it is enclosed.
`GDimension`	`getSize()` Returns the size of the bounding box for this object.
`double`	`getWidth()` Returns the width of this object, which is defined to be the width of the bounding box.
`double`	`getX()` Returns the x-coordinate of the object.
`double`	`getY()` Returns the y-coordinate of the object.
`boolean`	`isVisible()` Checks to see whether this object is visible.
`void`	`move(double dx, double dy)` Moves the object on the screen using the displacements `dx` and `dy`.
`void`	`movePolar(double r, double theta)` Moves the object using displacements given in polar coordinates.
`abstract void`	`paint(java.awt.Graphics g)` All subclasses of `GObject` must define a `paint` method which allows the object to draw itself on the `Graphics` context passed in as the parameter `g`.
`protected void`	`paintObject(java.awt.Graphics g)` Paints the object by setting up the necessary parameters and then dispatching to the `paint` procedure for this object.
`protected java.lang.String`	`paramString()` Returns a string indicating the parameters of this object.
`void`	`pause(double milliseconds)` Delays the calling thread for the specified time, which is expressed in milliseconds.
`void`	`removeActionListener(java.awt.event.ActionListener listener)` Removes an action listener from this graphical object.
`void`	`removeMouseListener(java.awt.event.MouseListener listener)` Removes a mouse listener from this graphical object.
`void`	`removeMouseMotionListener(java.awt.event.MouseMotionListener listener)` Removes a mouse motion listener from this graphical object.
`protected void`	`repaint()` Signals that the object needs to be repainted.
`void`	`sendBackward()` Moves this object one step toward the back in the z dimension.
`void`	`sendForward()` Moves this object one step toward the front in the z dimension.
`void`	`sendToBack()` Moves this object to the back of the display in the z dimension.
`void`	`sendToFront()` Moves this object to the front of the display in the z dimension.
`void`	`setColor(java.awt.Color color)` Sets the color used to display this object.
`void`	`setLocation(double x, double y)` Sets the location of this object to the point (`x`, `y`).
`void`	`setLocation(GPoint pt)` Sets the location of this object to the specified point.
`void`	`setParent(GContainer parent)` Sets the parent of this object, which should be called only by the `GContainer` in which this is installed.
`void`	`setVisible(boolean visible)` Sets whether this object is visible.
`protected void`	`start()` Starts a `GraphicsProgram` containing this object.
`protected void`	`start(java.lang.String[] args)` Starts a `GraphicsProgram` containing this object, passing it the specified arguments.
`java.lang.String`	`toString()` Overrides the `toString` method in `Object` to produce more readable output.
`protected void`	`updateEnabledList()` Tells the parent to update its list of enabled objects.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - GObject
```
protected GObject()
```
    Constructs a new GObject and initializes its state. This constructor is never called explicitly, but is instead invoked by the constructors of its subclasses.
- Method Detail
  - paint
```
public abstract void paint(java.awt.Graphics g)
```
    All subclasses of GObject must define a paint method which allows the object to draw itself on the Graphics context passed in as the parameter g.
    
    Parameters:
    
    g - The graphics context into which the painting is done
  - getBounds
```
public abstract GRectangle getBounds()
```
    Returns the bounding box of this object, which is defined to be the smallest rectangle that covers everything drawn by the figure. The coordinates of this rectangle do not necessarily match the location returned by getLocation. Given a GLabel object, for example, getLocation returns the coordinates of the point on the baseline at which the string begins; getBounds, by contrast, returns a rectangle that covers the entire window area occupied by the string.
    
    Returns:
    
    The bounding box for this object
  - setLocation
```
public void setLocation(double x,
                        double y)
```
    Sets the location of this object to the point (x, y).
    
    Parameters:
    
    x - The new x-coordinate for the object
    
    y - The new y-coordinate for the object
  - setLocation
```
public final void setLocation(GPoint pt)
```
    Sets the location of this object to the specified point.
    
    Parameters:
    
    pt - The new location for this object
  - getLocation
```
public GPoint getLocation()
```
    Returns the location of this object as a GPoint.
    
    Returns:
    
    The location of this object as a GPoint
  - getX
```
public double getX()
```
    Returns the x-coordinate of the object.
    
    Returns:
    
    The x-coordinate of the object
  - getY
```
public double getY()
```
    Returns the y-coordinate of the object.
    
    Returns:
    
    The y-coordinate of the object
  - move
```
public void move(double dx,
                 double dy)
```
    Moves the object on the screen using the displacements dx and dy.
    
    Parameters:
    
    dx - The distance to move the object in the x direction (positive is rightward)
    
    dy - The distance to move the object in the y direction (positive is downward)
  - movePolar
```
public final void movePolar(double r,
                            double theta)
```
    Moves the object using displacements given in polar coordinates. The parameter r specifies the distance to move and theta specifies the angle in which the motion occurs. The angle is measured in degrees increasing counterclockwise from the +x axis.
    
    Parameters:
    
    r - The distance to move
    
    theta - The angle in which to move, measured in degrees increasing counterclockwise from the +x axis
  - getSize
```
public GDimension getSize()
```
    Returns the size of the bounding box for this object.
    
    Returns:
    
    The size of this object
  - getWidth
```
public double getWidth()
```
    Returns the width of this object, which is defined to be the width of the bounding box.
    
    Returns:
    
    The width of this object on the screen
  - getHeight
```
public double getHeight()
```
    Returns the height of this object, which is defined to be the height of the bounding box.
    
    Returns:
    
    The height of this object on the screen
  - contains
```
public boolean contains(double x,
                        double y)
```
    Checks to see whether a point is inside the object. By default, this method simply checks to see if the point is inside the bounding box. Many subclasses will need to override this to check whether the point is contained in the shape.
    
    Parameters:
    
    x - The x-coordinate of the point being tested
    
    y - The y-coordinate of the point being tested
    
    Returns:
    
    true if the point (x, y) is inside the object, and false otherwise
  - contains
```
public final boolean contains(GPoint pt)
```
    Checks to see whether a point is inside the object.
    
    Parameters:
    
    pt - The point being tested
    
    Returns:
    
    true if the point is inside the object, and false otherwise
  - sendToFront
```
public void sendToFront()
```
    Moves this object to the front of the display in the z dimension. By moving it to the front, this object will appear to be on top of the other graphical objects on the display and may hide any objects that are further back.
  - sendToBack
```
public void sendToBack()
```
    Moves this object to the back of the display in the z dimension. By moving it to the back, this object will appear to be behind the other graphical objects on the display and may be obscured by other objects in front.
  - sendForward
```
public void sendForward()
```
    Moves this object one step toward the front in the z dimension. If it was already at the front of the stack, nothing happens.
  - sendBackward
```
public void sendBackward()
```
    Moves this object one step toward the back in the z dimension. If it was already at the back of the stack, nothing happens.
  - setColor
```
public void setColor(java.awt.Color color)
```
    Sets the color used to display this object.
    
    Parameters:
    
    color - The color used to display this object
  - getColor
```
public java.awt.Color getColor()
```
    Returns the color used to display this object.
    
    Returns:
    
    The color used to display this object
  - setVisible
```
public void setVisible(boolean visible)
```
    Sets whether this object is visible.
    
    Parameters:
    
    visible - true to make the object visible, false to hide it
  - isVisible
```
public boolean isVisible()
```
    Checks to see whether this object is visible.
    
    Returns:
    
    true if the object is visible, otherwise false
  - toString
```
public java.lang.String toString()
```
    Overrides the toString method in Object to produce more readable output.
    
    Overrides:
    
    toString in class java.lang.Object
  - getParent
```
public GContainer getParent()
```
    Returns the parent of this object, which is the canvas or compound object in which it is enclosed.
    
    Returns:
    
    The parent of this object
  - pause
```
public void pause(double milliseconds)
```
    Delays the calling thread for the specified time, which is expressed in milliseconds. Unlike Thread.sleep, this method never throws an exception.
    
    Parameters:
    
    milliseconds - The sleep time in milliseconds
  - addMouseListener
```
public void addMouseListener(java.awt.event.MouseListener listener)
```
    Adds a mouse listener to this graphical object.
    
    Parameters:
    
    listener - Any object that implements the MouseListener interface
  - removeMouseListener
```
public void removeMouseListener(java.awt.event.MouseListener listener)
```
    Removes a mouse listener from this graphical object.
    
    Parameters:
    
    listener - The listener object to remove
  - addMouseMotionListener
```
public void addMouseMotionListener(java.awt.event.MouseMotionListener listener)
```
    Adds a mouse motion listener to this graphical object.
    
    Parameters:
    
    listener - Any object that implements the MouseMotionListener interface
  - removeMouseMotionListener
```
public void removeMouseMotionListener(java.awt.event.MouseMotionListener listener)
```
    Removes a mouse motion listener from this graphical object.
    
    Parameters:
    
    listener - The listener object to remove
  - addActionListener
```
public void addActionListener(java.awt.event.ActionListener listener)
```
    Adds an action listener to this graphical object.
    
    Parameters:
    
    listener - Any object that implements the ActionListener interface
  - removeActionListener
```
public void removeActionListener(java.awt.event.ActionListener listener)
```
    Removes an action listener from this graphical object.
    
    Parameters:
    
    listener - The listener object to remove
  - fireActionEvent
```
public void fireActionEvent(java.lang.String actionCommand)
```
    Triggers an action event for this graphical object with the specified action command.
    
    Parameters:
    
    actionCommand - The action command to include in the event
  - fireActionEvent
```
public void fireActionEvent(java.awt.event.ActionEvent e)
```
    Triggers an action event for this graphical object.
    
    Parameters:
    
    e - The ActionEvent to fire
  - setParent
```
public void setParent(GContainer parent)
```
    Sets the parent of this object, which should be called only by the GContainer in which this is installed. The serialization behavior of the parent data depends on the parent type. Because a GCompound is serializable, it needs to be maintained in a nontransient variable; other parent classes are transient, so that these parents are not recorded in the serial form.
  - fireMouseListeners
```
protected void fireMouseListeners(java.awt.event.MouseEvent e)
```
    Sends the event to the appropriate listener.
    
    Parameters:
    
    e - The MouseEvent that triggered this response
  - areMouseListenersEnabled
```
protected boolean areMouseListenersEnabled()
```
    Returns true if mouse listeners have ever been assigned to this object.
    
    Returns:
    
    true if mouse listeners have been enabled in this object
  - start
```
protected void start()
```
    Starts a GraphicsProgram containing this object.
  - start
```
protected void start(java.lang.String[] args)
```
    Starts a GraphicsProgram containing this object, passing it the specified arguments.
    
    Parameters:
    
    args - The array of arguments
  - getObjectColor
```
protected java.awt.Color getObjectColor()
```
    This method returns the color set for this specific object, which may be null. It differs from getColor in that it does not walk up the containment chain.
  - paramString
```
protected java.lang.String paramString()
```
    Returns a string indicating the parameters of this object.
  - colorName
```
protected static java.lang.String colorName(java.awt.Color color)
```
    Translates a color to a string representation.
  - paintObject
```
protected void paintObject(java.awt.Graphics g)
```
    Paints the object by setting up the necessary parameters and then dispatching to the paint procedure for this object.
  - getComponent
```
protected java.awt.Component getComponent()
```
    Returns the component in which this object is installed, or null if none exists.
    
    Returns:
    
    The component in which this object is installed, or null if none exists
  - updateEnabledList
```
protected void updateEnabledList()
```
    Tells the parent to update its list of enabled objects.
  - repaint
```
protected void repaint()
```
    Signals that the object needs to be repainted.

Class GObject

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

GObject

Method Detail

paint

getBounds

setLocation

setLocation

getLocation

getX

getY

move

movePolar

getSize

getWidth

getHeight

contains

contains

sendToFront

sendToBack

sendForward

sendBackward

setColor

getColor

setVisible

isVisible

toString

getParent

pause

addMouseListener

removeMouseListener

addMouseMotionListener

removeMouseMotionListener

addActionListener

removeActionListener

fireActionEvent

fireActionEvent

setParent

fireMouseListeners

areMouseListenersEnabled

start

start

getObjectColor

paramString

colorName

paintObject

getComponent

updateEnabledList

repaint