accessiblehtml.java

Mobile 应用程序使用 Java Micro Edition (Java ME) 平台

	     * presented to a blind user to give an indication of the purpose
	     * of the icon.
	     *
	     * @return the description of the icon
	     */
	    public String getAccessibleIconDescription() {
		return ((ImageView)getView()).getAltText();
	    }
	
	    /**
	     * Sets the description of the icon.  This is meant to be a brief
	     * textual description of the object.  For example, it might be
	     * presented to a blind user to give an indication of the purpose
	     * of the icon.
	     *
	     * @param description the description of the icon
	     */
	    public void setAccessibleIconDescription(String description) {
	    }
	
	    /**
	     * Gets the width of the icon
	     *
	     * @return the width of the icon.
	     */
	    public int getAccessibleIconWidth() {
		if (width == -1) {
		    width = getImageSize(HTML.Attribute.WIDTH);
		}
		return width;
	    }
	    
	    /**
	     * Gets the height of the icon
	     *
	     * @return the height of the icon.
	     */
	    public int getAccessibleIconHeight() {
		if (height == -1) {
		    height = getImageSize(HTML.Attribute.HEIGHT);
		}
		return height;
	    }
	}
	// ... end AccessibleIconImplementation
    }


    /**
     * TableElementInfo encapsulates information about a HTML.Tag.TABLE.
     * To make access fast it crates a grid containing the children to
     * allow for access by row, column. TableElementInfo will contain
     * TableRowElementInfos, which will contain TableCellElementInfos.
     * Any time one of the rows or columns becomes invalid the table is
     * invalidated.  This is because any time one of the child attributes
     * changes the size of the grid may have changed.
     */
    private class TableElementInfo extends ElementInfo 
        implements Accessible {

	protected ElementInfo caption;

        /**
         * Allocation of the table by row x column. There may be holes (eg 
         * nulls) depending upon the html, any cell that has a rowspan/colspan
         * > 1 will be contained multiple times in the grid.
         */
        private TableCellElementInfo[][] grid;


        TableElementInfo(Element e, ElementInfo parent) {
            super(e, parent);
        }

	public ElementInfo getCaptionInfo() {
	    return caption;
	}

        /**
         * Overriden to update the grid when validating.
         */
        protected void validate() {
            super.validate();
            updateGrid();
        }

        /**
         * Overriden to only alloc instances of TableRowElementInfos.
         */
        protected void loadChildren(Element e) {

            for (int counter = 0; counter < e.getElementCount(); counter++) {
                Element child = e.getElement(counter);
                AttributeSet attrs = child.getAttributes();

                if (attrs.getAttribute(StyleConstants.NameAttribute) ==
                                       HTML.Tag.TR) {
                    addChild(new TableRowElementInfo(child, this, counter));

                } else if (attrs.getAttribute(StyleConstants.NameAttribute) ==
                                       HTML.Tag.CAPTION) {
		    // Handle captions as a special case since all other
		    // children are table rows.
		    caption = createElementInfo(child, this);
		}
            }
        }

        /**
         * Updates the grid.
         */
        private void updateGrid() {
            // Determine the max row/col count.
            int delta = 0;
            int maxCols = 0;
            int rows = 0;
            for (int counter = 0; counter < getChildCount(); counter++) {
                TableRowElementInfo row = getRow(counter);
                int prev = 0;
                for (int y = 0; y < delta; y++) {
                    prev = Math.max(prev, getRow(counter - y - 1).
                                    getColumnCount(y + 2));
                }
                delta = Math.max(row.getRowCount(), delta);
                delta--;
                maxCols = Math.max(maxCols, row.getColumnCount() + prev);
            }
            rows = getChildCount() + delta;

            // Alloc
            grid = new TableCellElementInfo[rows][];
            for (int counter = 0; counter < rows; counter++) {
                grid[counter] = new TableCellElementInfo[maxCols];
            }
            // Update
            for (int counter = 0; counter < rows; counter++) {
                getRow(counter).updateGrid(counter);
            }
        }

        /**
         * Returns the TableCellElementInfo at the specified index.
         */
        public TableRowElementInfo getRow(int index) {
            return (TableRowElementInfo)getChild(index);
        }

        /**
         * Returns the TableCellElementInfo by row and column.
         */
        public TableCellElementInfo getCell(int r, int c) {
            if (validateIfNecessary() && r < grid.length &&
                                         c < grid[0].length) {
                return grid[r][c];
            }
            return null;
        }

        /**
         * Returns the rowspan of the specified entry.
         */
        public int getRowExtentAt(int r, int c) {
            TableCellElementInfo cell = getCell(r, c);

            if (cell != null) {
                int rows = cell.getRowCount();
                int delta = 1;

                while ((r - delta) >= 0 && grid[r - delta][c] == cell) {
                    delta++;
                }
                return rows - delta + 1;
            }
            return 0;
        }

        /**
         * Returns the colspan of the specified entry.
         */
        public int getColumnExtentAt(int r, int c) {
            TableCellElementInfo cell = getCell(r, c);

            if (cell != null) {
                int cols = cell.getColumnCount();
                int delta = 1;

                while ((c - delta) >= 0 && grid[r][c - delta] == cell) {
                    delta++;
                }
                return cols - delta + 1;
            }
            return 0;
        }

        /**
         * Returns the number of rows in the table.
         */
        public int getRowCount() {
            if (validateIfNecessary()) {
                return grid.length;
            }
            return 0;
        }

        /**
         * Returns the number of columns in the table.
         */
        public int getColumnCount() {
            if (validateIfNecessary() && grid.length > 0) {
                return grid[0].length;
            }
            return 0;
        }

	// begin AccessibleTable implementation ...
	private AccessibleContext accessibleContext;
	
	public AccessibleContext getAccessibleContext() {
	    if (accessibleContext == null) {
		accessibleContext = new TableAccessibleContext(this);
	    }
	    return accessibleContext;
	}
	
	/*
	 * AccessibleContext for tables
	 */
	public class TableAccessibleContext extends HTMLAccessibleContext
            implements AccessibleTable {

	    private AccessibleHeadersTable rowHeadersTable;

	    public TableAccessibleContext(ElementInfo elementInfo) {
		super(elementInfo);
	    }
	    
	    /**
	     * Gets the accessibleName property of this object.  The accessibleName
	     * property of an object is a localized String that designates the purpose
	     * of the object.  For example, the accessibleName property of a label
	     * or button might be the text of the label or button itself.  In the
	     * case of an object that doesn't display its name, the accessibleName
	     * should still be set.  For example, in the case of a text field used
	     * to enter the name of a city, the accessibleName for the en_US locale
	     * could be 'city.'
	     *
	     * @return the localized name of the object; null if this 
	     * object does not have a name
	     *
	     * @see #setAccessibleName
	     */
	    public String getAccessibleName() {
		// return the role of the object
		return getAccessibleRole().toString();
	    }
	    
	    /**
	     * Gets the accessibleDescription property of this object.  If this
	     * property isn't set, returns the content type of this
	     * <code>JEditorPane</code> instead (e.g. "plain/text", "html/text").
	     *
	     * @return the localized description of the object; <code>null</code>
	     * 	if this object does not have a description
	     *
	     * @see #setAccessibleName
	     */
	    public String getAccessibleDescription() {
		return editor.getContentType();
	    }
	    
	    /**
	     * Gets the role of this object.  The role of the object is the generic
	     * purpose or use of the class of this object.  For example, the role
	     * of a push button is AccessibleRole.PUSH_BUTTON.  The roles in 
	     * AccessibleRole are provided so component developers can pick from
	     * a set of predefined roles.  This enables assistive technologies to
	     * provide a consistent interface to various tweaked subclasses of 
	     * components (e.g., use AccessibleRole.PUSH_BUTTON for all components
	     * that act like a push button) as well as distinguish between sublasses
	     * that behave differently (e.g., AccessibleRole.CHECK_BOX for check boxes
	     * and AccessibleRole.RADIO_BUTTON for radio buttons).
	     * <p>Note that the AccessibleRole class is also extensible, so 
	     * custom component developers can define their own AccessibleRole's
	     * if the set of predefined roles is inadequate.
	     *
	     * @return an instance of AccessibleRole describing the role of the object
	     * @see AccessibleRole
	     */
	    public AccessibleRole getAccessibleRole() {
		return AccessibleRole.TABLE;
	    }
	    
	    /**
	     * Gets the 0-based index of this object in its accessible parent.
	     *
	     * @return the 0-based index of this object in its parent; -1 if this 
	     * object does not have an accessible parent.
	     *
	     * @see #getAccessibleParent 
	     * @see #getAccessibleChildrenCount
	     * @gsee #getAccessibleChild
	     */
	    public int getAccessibleIndexInParent() {
		return elementInfo.getIndexInParent();
	    }
	    
	    /**
	     * Returns the number of accessible children of the object.
	     *
	     * @return the number of accessible children of the object.
	     */
	    public int getAccessibleChildrenCount() {
		return ((TableElementInfo)elementInfo).getRowCount() * 
		    ((TableElementInfo)elementInfo).getColumnCount();
	    }
	    
	    /**
	     * Returns the specified Accessible child of the object.  The Accessible
	     * children of an Accessible object are zero-based, so the first child 
	     * of an Accessible child is at index 0, the second child is at index 1,
	     * and so on.
	     *
	     * @param i zero-based index of child
	     * @return the Accessible child of the object
	     * @see #getAccessibleChildrenCount
	     */
	    public Accessible getAccessibleChild(int i) {
		int rowCount = ((TableElementInfo)elementInfo).getRowCount();
		int columnCount = ((TableElementInfo)elementInfo).getColumnCount();
		int r = i / rowCount;
		int c = i % columnCount;
		if (r < 0 || r >= rowCount || c < 0 || c >= columnCount) {
		    return null;
		} else {
		    return getAccessibleAt(r, c);
		}
	    }
	    
	    public AccessibleTable getAccessibleTable() {
		return this;
	    }
	    
	    /**
	     * Returns the caption for the table.
	     *
	     * @return the caption for the table
	     */
	    public Accessible getAccessibleCaption() {
		ElementInfo captionInfo = getCaptionInfo();
		if (captionInfo instanceof Accessible) {
		    return (Accessible)caption;
		} else {
		    return null;
		}
	    }
	    
	    /**
	     * Sets the caption for the table.
	     *
	     * @param a the caption for the table
	     */
	    public void setAccessibleCaption(Accessible a) {
	    }
	    
	    /**
	     * Returns the summary description of the table.
	     * 
	     * @return the summary description of the table
	     */
	    public Accessible getAccessibleSummary() {
		return null;	
	    }
	    
	    /**
	     * Sets the summary description of the table
	     *
	     * @param a the summary description of the table
	     */
	    public void setAccessibleSummary(Accessible a) {
	    }
	    
	    /**
	     * Returns the number of rows in the table.
	     *
	     * @return the number of rows in the table
	     */
	    public int getAccessibleRowCount() {
		return ((TableElementInfo)elementInfo).getRowCount();
	    }
	    
	    /**
	     * Returns the number of columns in the table.
	     *
	     * @return the number of columns in the table
	     */
	    public int getAccessibleColumnCount() {
		return ((TableElementInfo)elementInfo).getColumnCount();
	    }
	    
	    /**
	     * Returns the Accessible at a specified row and column
	     * in the table.
	     *
	     * @param r zero-based row of the table
	     * @param c zero-based column of the table
	     * @return the Accessible at the specified row and column
	     */
	    public Accessible getAccessibleAt(int r, int c) {
		TableCellElementInfo cellInfo = getCell(r, c);
		if (cellInfo != null) {
		    return cellInfo.getAccessible();
		} else {
		    return null;
		}
	    }
	    
	    /**
	     * Returns the number of rows occupied by the Accessible at
	     * a specified row and column in the table.
	     *
	     * @return the number of rows occupied by the Accessible at a
	     * given specified (row, column)
	     */
	    public int getAccessibleRowExtentAt(int r, int c) {
		return ((TableElementInfo)elementInfo).getRowExtentAt(r, c);
	    }
	    
	    /**
	     * Returns the number of columns occupied by the Accessible at
	     * a specified row and column in the table.
	     *
	     * @return the number of columns occupied by the Accessible at a
	     * given specified row and column
	     */
	    public int getAccessibleColumnExtentAt(int r, int c) {
		return ((TableElementInfo)elementInfo).getColumnExtentAt(r, c);
	    }
	    
	    /**
	     * Returns the row headers as an AccessibleTable.
	     *
	     * @return an AccessibleTable representing the row
	     * headers
	     */
	    public AccessibleTable getAccessibleRowHeader() {