title.java

jfreechart安装程序和使用说明

        if (alignment == null) {
            throw new IllegalArgumentException("Null 'alignment' argument.");
        }
        if (this.horizontalAlignment != alignment) {
            this.horizontalAlignment = alignment;
            notifyListeners(new TitleChangeEvent(this));
        }
    }

    /**
     * Returns the vertical alignment of the title.
     *
     * @return the vertical alignment (never <code>null</code>).
     */
    public VerticalAlignment getVerticalAlignment() {
        return this.verticalAlignment;
    }

    /**
     * Sets the vertical alignment for the title, and notifies any registered
     * listeners of the change.
     *
     * @param alignment  the new vertical alignment (TOP, MIDDLE or BOTTOM, 
     *                   <code>null</code> not permitted).
     */
    public void setVerticalAlignment(VerticalAlignment alignment) {
        if (alignment == null) {
            throw new IllegalArgumentException("Argument 'alignment' cannot be null.");
        }
        if (this.verticalAlignment != alignment) {
            this.verticalAlignment = alignment;
            notifyListeners(new TitleChangeEvent(this));
        }
    }

    /**
     * Returns the spacer  which determines the blank space around the edges of the title.
     *
     * @return The spacer (never <code>null</code>).
     */
    public Spacer getSpacer() {
        return this.spacer;
    }

    /**
     * Sets the spacer for the title and sends a {@link TitleChangeEvent} to all registered 
     * listeners.
     *
     * @param spacer  the new spacer (<code>null</code> not permitted).
     */
    public void setSpacer(Spacer spacer) {
        if (spacer == null) {
            throw new NullPointerException("AbstractTitle.setSpacer(): null not permitted.");
        }
        if (!this.spacer.equals(spacer)) {
            this.spacer = spacer;
            notifyListeners(new TitleChangeEvent(this));
        }

    }

    /**
     * Returns the flag that indicates whether or not the notification mechanism is enabled.
     *
     * @return the flag.
     */
    public boolean getNotify() {
        return this.notify;
    }

    /**
     * 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.
     *
     * @param flag  the new value of the flag.
     */
    public void setNotify(boolean flag) {
        this.notify = flag;
    }

    /**
     * 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.
     *
     * @param g2  the graphics device.
     * @param height  the height.
     *
     * @return the preferred width of the title.
     */
    public abstract float getPreferredWidth(Graphics2D g2, float height);

    /**
     * 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.
     *
     * @param g2  the graphics device.
     * @param width  the width.
     *
     * @return the preferred height of the title.
     */
    public abstract float getPreferredHeight(Graphics2D g2, float width);

    /**
     * Draws the title on a Java 2D graphics device (such as the screen or a printer).
     *
     * @param g2  the graphics device.
     * @param area  the area allocated for the title.
     */
    public abstract void draw(Graphics2D g2, Rectangle2D area);

    /**
     * Returns a clone of the title.
     * <P>
     * 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.
     *
     * @return a clone of the title.
     *
     * @throws CloneNotSupportedException not thrown by this class, but it may be thrown by
     *         subclasses.
     */
    public Object clone() throws CloneNotSupportedException {

        Title duplicate = (Title) super.clone();
        duplicate.listenerList = new EventListenerList();
        // Spacer is immutable => same reference in clone OK
        return duplicate;
    }

    /**
     * Registers an object for notification of changes to the title.
     *
     * @param listener  the object that is being registered.
     */
    public void addChangeListener(TitleChangeListener listener) {
        this.listenerList.add(TitleChangeListener.class, listener);
    }

    /**
     * Unregisters an object for notification of changes to the chart title.
     *
     * @param listener  the object that is being unregistered.
     */
    public void removeChangeListener(TitleChangeListener listener) {
        this.listenerList.remove(TitleChangeListener.class, listener);
    }

    /**
     * Notifies all registered listeners that the chart title has changed in some way.
     *
     * @param event  an object that contains information about the change to the title.
     */
    protected void notifyListeners(TitleChangeEvent event) {

        if (this.notify) {

            Object[] listeners = this.listenerList.getListenerList();
            for (int i = listeners.length - 2; i >= 0; i -= 2) {
                if (listeners[i] == TitleChangeListener.class) {
                    ((TitleChangeListener) listeners[i + 1]).titleChanged(event);
                }
            }
        }

    }

    /**
     * Tests an object for equality with this title.
     *
     * @param obj  the object.
     *
     * @return <code>true</code> or <code>false</code>.
     */
    public boolean equals(Object obj) {

        if (obj == null) {
            return false;
        }

        if (obj == this) {
            return true;
        }

        if (obj instanceof Title) {

            Title t = (Title) obj;

            if (this.position != t.position) {
                return false;
            }
            if (this.horizontalAlignment != t.horizontalAlignment) {
                return false;
            }
            if (this.verticalAlignment != t.verticalAlignment) {
                return false;
            }
            if (!ObjectUtils.equal(this.spacer, t.spacer)) {
                return false;
            }
            if (this.notify != t.notify) {
                return false;
            }

            return true;

        }

        return false;

    }

    /**
     * Returns a hashcode for the title.
     * 
     * @return the hashcode.
     */
    public int hashCode() {
        int result = 193;
        result = 37 * result + ObjectUtils.hashCode(this.position);    
        result = 37 * result + ObjectUtils.hashCode(this.horizontalAlignment);    
        result = 37 * result + ObjectUtils.hashCode(this.verticalAlignment);    
        result = 37 * result + ObjectUtils.hashCode(this.spacer);    
        return result;
    }
        
    /**
     * Provides serialization support.
     *
     * @param stream  the output stream.
     *
     * @throws IOException  if there is an I/O error.
     */
    private void writeObject(ObjectOutputStream stream) throws IOException {
        stream.defaultWriteObject();
    }

    /**
     * Provides serialization support.
     *
     * @param stream  the input stream.
     *
     * @throws IOException  if there is an I/O error.
     * @throws ClassNotFoundException  if there is a classpath problem.
     */
    private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
        stream.defaultReadObject();
        this.listenerList = new EventListenerList();
    }

}