rtarootview.java~1~

具有不同语法高亮的编辑器实例

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        /** 
         * Returns the number of views in this view.  Since
         * this view simply wraps the root of the view hierarchy
         * it has exactly one child.
         *
         * @return the number of views
         * @see #getView
         */
        public int getViewCount() {
            return 1;
        }


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        /**
         * Fetches the factory to be used for building the
         * various view fragments that make up the view that
         * represents the model.  This is what determines
         * how the model will be represented.  This is implemented
         * to fetch the factory provided by the associated
         * EditorKit unless that is null, in which case this
         * simply returns the BasicTextUI itself which allows
         * subclasses to implement a simple factory directly without
         * creating extra objects.  
         *
         * @return the factory
         */
        public ViewFactory getViewFactory() {
            EditorKit kit = ui.getEditorKit(editor);
            ViewFactory f = kit.getViewFactory();
            if (f != null) {
                return f;
            }
            return ui;
        }


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	/**
	 * Returns the child view index representing the given position in
	 * the model.  This is implemented to return the index of the only
	 * child.
	 *
	 * @param pos the position >= 0
	 * @return  index of the view representing the given position, or 
	 *   -1 if no view represents that position
	 * @since 1.3
	 */
        public int getViewIndex(int pos, Position.Bias b) {
	    return 0;
	}
    

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        /**
         * Gives notification that something was inserted into the document
         * in a location that this view is responsible for.
         *
         * @param e the change information from the associated document
         * @param a the current allocation of the view
         */
        public void insertUpdate(DocumentEvent e, Shape a) {
            if (view != null)
                view.insertUpdate(e, a, getViewFactory());
        }
        

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	/**
	 * Provides a mapping from the document model coordinate space
	 * to the coordinate space of the view mapped to it.
	 *
	 * @param pos the position to convert
	 * @param a the allocated region to render into
	 * @return the bounding box of the given position
	 */
	public Shape modelToView(int pos, Shape a, Position.Bias b)
									throws BadLocationException {
		if (view != null) {
			return view.modelToView(pos, a, b);
		}
		return null;
	}


/*****************************************************************************/


	/**
	 * Provides a mapping from the document model coordinate space
	 * to the coordinate space of the view mapped to it.
	 *
	 * @param p0 the position to convert >= 0
	 * @param b0 the bias toward the previous character or the
	 *  next character represented by p0, in case the 
	 *  position is a boundary of two views. 
	 * @param p1 the position to convert >= 0
	 * @param b1 the bias toward the previous character or the
	 *  next character represented by p1, in case the 
	 *  position is a boundary of two views. 
	 * @param a the allocated region to render into
	 * @return the bounding box of the given position is returned
	 * @exception BadLocationException  if the given position does
	 *   not represent a valid location in the associated document
	 * @exception IllegalArgumentException for an invalid bias argument
	 * @see View#viewToModel
	 */
	public Shape modelToView(int p0, Position.Bias b0,
						int p1, Position.Bias b1,
						Shape a) throws BadLocationException {
		if (view != null)
			return view.modelToView(p0, b0, p1, b1, a);
		return null;
	}


/*****************************************************************************/


	/**
	 * Renders the view.
	 *
	 * @param g the graphics context
	 * @param allocation the region to render into
	 */
	public void paint(Graphics g, Shape allocation) {
		if (view != null) {
			Rectangle alloc = (allocation instanceof Rectangle) ?
						(Rectangle)allocation : allocation.getBounds();
			setSize(alloc.width, alloc.height);
			view.paint(g, allocation);
		}
	}
        

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        /**
         * Specifies that a preference has changed.
         * Child views can call this on the parent to indicate that
         * the preference has changed.  The root view routes this to
         * invalidate on the hosting component.
         * <p>
         * This can be called on a different thread from the
         * event dispatching thread and is basically unsafe to
         * propagate into the component.  To make this safe,
         * the operation is transferred over to the event dispatching 
         * thread for completion.  It is a design goal that all view
         * methods be safe to call without concern for concurrency,
         * and this behavior helps make that true.
         *
         * @param child the child view
         * @param width true if the width preference has changed
         * @param height true if the height preference has changed
         */ 
        public void preferenceChanged(View child, boolean width, boolean height) {
            editor.revalidate();
        }


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        /**
         * Gives notification that something was removed from the document
         * in a location that this view is responsible for.
         *
         * @param e the change information from the associated document
         * @param a the current allocation of the view
         */
        public void removeUpdate(DocumentEvent e, Shape a) {
            if (view != null) {
                view.removeUpdate(e, a, getViewFactory());
            }
        }


/*****************************************************************************/


	/**
	 * Sets the view parent.
	 *
	 * @param parent the parent view
	 */
	public void setParent(View parent) {
		throw new Error("Can't set parent on root view");
	}


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	/**
	 * Sets the view that this view displays.
	 *
	 * @param v The view.
	 */
	void setView(View v) {

		View oldView = view;
		view = null;
		if (oldView != null) {
			// get rid of back reference so that the old
			// hierarchy can be garbage collected.
			oldView.setParent(null);
		}
		if (v != null) {
			v.setParent(this);
		}
		view = v;
	}


/*****************************************************************************/


	/**
	 * Provides a mapping from the view coordinate space to the logical
	 * coordinate space of the model.
	 *
	 * @param x x coordinate of the view location to convert
	 * @param y y coordinate of the view location to convert
	 * @param a the allocated region to render into
	 * @return the location within the model that best represents the
	 *    given point in the view
	 */
	public int viewToModel(float x, float y, Shape a, Position.Bias[] bias) {
		if (view != null)
			return view.viewToModel(x, y, a, bias);
		return -1;
	}


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        /**
         * Breaks this view on the given axis at the given length.
         *
         * @param axis may be either X_AXIS or Y_AXIS
         * @param len specifies where a break is desired in the span
         * @param the current allocation of the view
         * @return the fragment of the view that represents the given span
         *   if the view can be broken, otherwise null
         */
        public View breakView(int axis, float len, Shape a) {
            throw new Error("Can't break root view");
        }


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        /**
         * Determines the resizability of the view along the
         * given axis.  A value of 0 or less is not resizable.
         *
         * @param axis may be either X_AXIS or Y_AXIS
         * @return the weight
         */
        public int getResizeWeight(int axis) {
            if (view != null) {
                return view.getResizeWeight(axis);
            }
            return 0;
        }


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        /**
         * Sets the view size.
         *
         * @param width the width
         * @param height the height
         */
        public void setSize(float width, float height) {
            if (view != null) {
                view.setSize(width, height);
            }
        }


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}