org.jfree.chart
Class AbstractTitle

java.lang.Object
  |
  +--org.jfree.chart.AbstractTitle

All Implemented Interfaces:

java.lang.Cloneable, java.io.Serializable

Direct Known Subclasses:

ImageTitle, LegendTitle, TextTitle

public abstract class AbstractTitle

extends java.lang.Object

implements java.lang.Cloneable, java.io.Serializable

The base class for all chart titles.

A chart can have multiple titles, appearing at the top, bottom, left or right of the chart (defined by the constants TOP, BOTTOM, LEFT and RIGHT --- we also use the constants NORTH, SOUTH, EAST and WEST to remain consistent with java.awt.BorderLayout, as most developers will be familiar with that class).

Concrete implementations of this class will render text, images, and hence do the actual work of drawing titles.

Author:

David Berry

See Also:

Serialized Form

Field Summary

static int	BOTTOM Useful constant for the title position (also used for vertical alignment).
static int	CENTER Useful constant for the title alignment (horizontal or vertical).
static int	DEFAULT_HORIZONTAL_ALIGNMENT The default horizontal alignment.
static int	DEFAULT_POSITION The default title position.
static Spacer	DEFAULT_SPACER Default title spacer.
static int	DEFAULT_VERTICAL_ALIGNMENT The default vertical alignment.
static int	EAST Useful constant for the title position.
static int	LEFT Useful constant for the title position (also used for horizontal alignment).
static int	MIDDLE Useful constant for the title alignment (horizontal or vertical).
static int	NORTH Useful constant for the title position.
static int	RIGHT Useful constant for the title position (also used for horizontal alignment).
static int	SOUTH Useful constant for the title position.
static int	TOP Useful constant for the title position (also used for vertical alignment).
static int	WEST Useful constant for the title position.

Constructor Summary

protected	AbstractTitle() Creates a new title, using default attributes where necessary.
protected	AbstractTitle(int position, int horizontalAlignment, int verticalAlignment) Creates a new title, using default attributes where necessary.
protected	AbstractTitle(int position, int horizontalAlignment, int verticalAlignment, Spacer spacer) Constructs a new AbstractTitle.

Method Summary

void	addChangeListener(TitleChangeListener listener) Registers an object for notification of changes to the title.
java.lang.Object	clone() Returns a clone of the title.
abstract void	draw(java.awt.Graphics2D g2, java.awt.geom.Rectangle2D titleArea) Draws the title on a Java 2D graphics device (such as the screen or a printer).
boolean	equals(java.lang.Object obj) Tests an object for equality with this title.
int	getHorizontalAlignment() Returns the horizontal alignment of the title.
boolean	getNotify() Returns the flag that indicates whether or not the notification mechanism is enabled.
int	getPosition() Returns the relative position of the title---represented by one of four integer constants defined in this class: TOP, BOTTOM, RIGHT or LEFT (or the equivalent NORTH, SOUTH, EAST and WEST).
abstract double	getPreferredHeight(java.awt.Graphics2D g2) Returns the preferred height of the title.
abstract double	getPreferredWidth(java.awt.Graphics2D g2) Returns the preferred width of the title.
Spacer	getSpacer() Returns the spacer (determines the blank space around the edges) for this title.
int	getVerticalAlignment() Returns the vertical alignment of the title.
protected static boolean	isValidHorizontalAlignment(int code) Utility method for checking a horizontal alignment code.
abstract boolean	isValidPosition(int position) Returns true if the title can assume the specified location, and false otherwise.
protected static boolean	isValidVerticalAlignment(int code) Utility method for checking a vertical alignment code.
protected void	notifyListeners(TitleChangeEvent event) Notifies all registered listeners that the chart title has changed in some way.
void	removeChangeListener(TitleChangeListener listener) Unregisters an object for notification of changes to the chart title.
void	setHorizontalAlignment(int alignment) Sets the horizontal alignment for the title, and notifies any registered listeners of the change.
void	setNotify(boolean flag) Sets the flag that indicates whether or not the notification mechanism is enabled.
void	setPosition(int position) Sets the position for the title.
void	setSpacer(Spacer spacer) Sets the spacer for the title, and notifies registered listeners of the change.
void	setVerticalAlignment(int alignment) Sets the vertical alignment for the title, and notifies any registered listeners of the change.

Methods inherited from class java.lang.Object

finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

TOP

public static final int TOP

Useful constant for the title position (also used for vertical alignment).

See Also:

Constant Field Values

BOTTOM

public static final int BOTTOM

Useful constant for the title position (also used for vertical alignment).

See Also:

Constant Field Values

RIGHT

public static final int RIGHT

Useful constant for the title position (also used for horizontal alignment).

See Also:

Constant Field Values

LEFT

public static final int LEFT

Useful constant for the title position (also used for horizontal alignment).

See Also:

Constant Field Values

NORTH

public static final int NORTH

Useful constant for the title position.

See Also:

Constant Field Values

SOUTH

public static final int SOUTH

Useful constant for the title position.

See Also:

Constant Field Values

EAST

public static final int EAST

Useful constant for the title position.

See Also:

Constant Field Values

WEST

public static final int WEST

Useful constant for the title position.

See Also:

Constant Field Values

CENTER

public static final int CENTER

Useful constant for the title alignment (horizontal or vertical).

See Also:

Constant Field Values

MIDDLE

public static final int MIDDLE

Useful constant for the title alignment (horizontal or vertical).

See Also:

Constant Field Values

DEFAULT_POSITION

public static final int DEFAULT_POSITION

The default title position.

See Also:

Constant Field Values

DEFAULT_HORIZONTAL_ALIGNMENT

public static final int DEFAULT_HORIZONTAL_ALIGNMENT

The default horizontal alignment.

See Also:

Constant Field Values

DEFAULT_VERTICAL_ALIGNMENT

public static final int DEFAULT_VERTICAL_ALIGNMENT

The default vertical alignment.

See Also:

Constant Field Values

DEFAULT_SPACER

public static final Spacer DEFAULT_SPACER

Default title spacer.

Constructor Detail

AbstractTitle

protected AbstractTitle()

Creates a new title, using default attributes where necessary.

AbstractTitle

protected AbstractTitle(int position,
                        int horizontalAlignment,
                        int verticalAlignment)

Creates a new title, using default attributes where necessary.

Parameters:

position - the relative position of the title (TOP, BOTTOM, RIGHT and LEFT).

horizontalAlignment - the horizontal alignment of the title (LEFT, CENTER or RIGHT).

verticalAlignment - the vertical alignment of the title (TOP, MIDDLE or BOTTOM).

Throws:

java.lang.IllegalArgumentException - if an invalid location or alignment value is passed.

AbstractTitle

protected AbstractTitle(int position,
                        int horizontalAlignment,
                        int verticalAlignment,
                        Spacer spacer)

Constructs a new AbstractTitle.

This class defines constants for the valid position and alignment values --- an IllegalArgumentException will be thrown if invalid values are passed to this constructor.

Parameters:

position - the relative position of the title (TOP, BOTTOM, RIGHT and LEFT).

horizontalAlignment - the horizontal alignment of the title (LEFT, CENTER or RIGHT).

verticalAlignment - the vertical alignment of the title (TOP, MIDDLE or BOTTOM).

spacer - the amount of space to leave around the outside of the title.

Throws:

java.lang.IllegalArgumentException - if an invalid location or alignment value is passed.

Method Detail

getPosition

public int getPosition()

Returns the relative position of the title---represented by one of four integer constants defined in this class: TOP, BOTTOM, RIGHT or LEFT (or the equivalent NORTH, SOUTH, EAST and WEST).

Returns:

The title position.

setPosition

public void setPosition(int position)

Sets the position for the title.

Parameters:

position - the relative position of the title (use one of the constants TOP, BOTTOM, RIGHT and LEFT, or the equivalent NORTH, SOUTH, EAST and WEST).

getHorizontalAlignment

public int getHorizontalAlignment()

Returns the horizontal alignment of the title. The constants LEFT, CENTER and RIGHT (defined in this class) are used.

Returns:

the horizontal alignment of the title (LEFT, CENTER or RIGHT).

setHorizontalAlignment

public void setHorizontalAlignment(int alignment)

Sets the horizontal alignment for the title, and notifies any registered listeners of the change. The constants LEFT, CENTER and RIGHT (defined in this class) can be used to specify the alignment.

Parameters:

alignment - the new horizontal alignment (LEFT, CENTER or RIGHT).

getVerticalAlignment

public int getVerticalAlignment()

Returns the vertical alignment of the title. The constants TOP, MIDDLE and BOTTOM (defined in this class) are used.

Returns:

the vertical alignment of the title (TOP, MIDDLE or BOTTOM).

setVerticalAlignment

public void setVerticalAlignment(int alignment)

Sets the vertical alignment for the title, and notifies any registered listeners of the change. The constants TOP, MIDDLE and BOTTOM (defined in this class) can be used to specify the alignment.

Parameters:

alignment - the new vertical alignment (TOP, MIDDLE or BOTTOM).

getSpacer

public Spacer getSpacer()

Returns the spacer (determines the blank space around the edges) for this title.

Returns:

the spacer for this title.

setSpacer

public void setSpacer(Spacer spacer)

Sets the spacer for the title, and notifies registered listeners of the change.

Parameters:

spacer - the new spacer.

getNotify

public boolean getNotify()

Returns the flag that indicates whether or not the notification mechanism is enabled.

Returns:

the flag.

setNotify

public void setNotify(boolean flag)

Sets the flag that indicates whether or not the notification mechanism is enabled. There are certain situations (such as cloning) where you want to turn notification off temporarily.

Parameters:

flag - the new value of the flag.

isValidPosition

public abstract boolean isValidPosition(int position)

Returns true if the title can assume the specified location, and false otherwise.

Parameters:

position - the position.

Returns:

true if the title can assume the specified position.

getPreferredWidth

public abstract double getPreferredWidth(java.awt.Graphics2D g2)

Returns the preferred width of the title. When a title is displayed at the left or right of a chart, the chart will attempt to give the title enough space for it's preferred width.

Parameters:

g2 - the graphics device.

Returns:

the preferred width of the title.

getPreferredHeight

public abstract double getPreferredHeight(java.awt.Graphics2D g2)

Returns the preferred height of the title. When a title is displayed at the top or bottom of a chart, the chart will attempt to give the title enough space for it's preferred height.

Parameters:

g2 - the graphics device.

Returns:

the preferred height of the title.

draw

public abstract void draw(java.awt.Graphics2D g2,
                          java.awt.geom.Rectangle2D titleArea)

Draws the title on a Java 2D graphics device (such as the screen or a printer).

Parameters:

g2 - the graphics device.

titleArea - the area for drawing the title.

clone

public java.lang.Object clone()

Returns a clone of the title.

One situation when this is useful is when editing the title properties - you can edit a clone, and then it is easier to cancel the changes if necessary.

Overrides:

clone in class java.lang.Object

Returns:

a clone of the title.

addChangeListener

public void addChangeListener(TitleChangeListener listener)

Registers an object for notification of changes to the title.

Parameters:

listener - the object that is being registered.

removeChangeListener

public void removeChangeListener(TitleChangeListener listener)

Unregisters an object for notification of changes to the chart title.

Parameters:

listener - the object that is being unregistered.

notifyListeners

protected void notifyListeners(TitleChangeEvent event)

Notifies all registered listeners that the chart title has changed in some way.

Parameters:

event - an object that contains information about the change to the title.

isValidHorizontalAlignment

protected static boolean isValidHorizontalAlignment(int code)

Utility method for checking a horizontal alignment code.

Parameters:

code - the alignment code.

Returns:

true if alignment is LEFT|MIDDLE|RIGHT.

isValidVerticalAlignment

protected static boolean isValidVerticalAlignment(int code)

Utility method for checking a vertical alignment code.

Parameters:

code - the alignment code.

Returns:

true, if alignment is TOP|MIDDLE|BOTTOM.

equals

public boolean equals(java.lang.Object obj)

Tests an object for equality with this title.

Overrides:

equals in class java.lang.Object

Parameters:

obj - the object.

Returns:

true or false.