org.apache.beehive.netui.tags.databinding.datagrid
Class AbstractCell

Object
  SimpleTagSupport
      AbstractSimpleTag
          AbstractDataGridHtmlTag
              AbstractCell

All Implemented Interfaces:

JspTag, SimpleTag, INetuiTag

Direct Known Subclasses:

AbstractHtmlTableCell, HeaderCell

public abstract class AbstractCell
extends AbstractDataGridHtmlTag

Abstract base class for JSP tags that render data grid cells. This class provides support to subclasses in several areas:

• formatting -- this class accepts instances of FormatTag.Formatter which can optionally be used by a subclass to perform formatting on content that is written to a rendered page
• applying attributes
• applying state attributes to AbstractHtmlState instances used by subclasses.

AbstractCell

public AbstractCell()

addFormatter

public void addFormatter(FormatTag.Formatter formatter)

Add a FormatTag.Formatter. Subclasses can optionally use the support formatting; formatters are added to the CellModel associated with an instance of the subclass.

Parameters:

formatter - the formatter to add

formatterHasError

public void formatterHasError()

Indicate that a formatter has reported an error so the formatter should output it's body text.

doTag

public void doTag()
           throws JspException,
                  IOException

This method implements the rendering process for data grid cells. When the data grid's rendering state is not DataGridTagModel.RENDER_STATE_START, this tag processes its body. The tag performs the following steps in order:

1. The tag invokes its applyAttributes() method to allow subclasses to apply attributes to their CellModel instances at a well known time. Any errors in attribute checking should be thrown here.
2. The tag adds the CellModel associated with the data grid to the JspContext under the key cellModel.
3. Rendering is performed by invoking renderCell(org.apache.beehive.netui.tags.rendering.AbstractRenderAppender). If content is rendered when the body of the tag is rendered, it is written to the output stream.
4. The tag removes the CellModel instance. If an exception is thrown after the CellModel is added to the JspContext, it the cell model will still be removed from the JspContext.

Specified by:

doTag in interface SimpleTag

Overrides:

doTag in class SimpleTagSupport

Throws:

JspException

IOException

internalGetCellModel

protected abstract CellModel internalGetCellModel()

Abstract method implemented by subclasses. Implementers should return the CellModel associated with the UI that is being rendered by the JSP tag.

Returns:

the cell's CellModel

renderCell

protected abstract void renderCell(AbstractRenderAppender appender)
                            throws IOException,
                                   JspException

Abstract method implemented by subclasses to perform cell-specific rendering.

Parameters:

appender - the AbstractRenderAppender to which any output should be rendered

Throws:

IOException

JspException

renderEmptyCell

protected void renderEmptyCell(AbstractRenderAppender appender)

Utility method usable by subclasses that renders an HTML   to represent an empty HTML table cell.

Parameters:

appender - the AbstractRenderAppender to which any output should be rendered

applyAttributes

protected void applyAttributes()
                        throws JspException

Utility method invoked during tag rendering. Subclasses should place attribute validation logic here.

Throws:

JspException - if application of attributes fails

addStateAttribute

protected final void addStateAttribute(AbstractHtmlState state,
                                       String name,
                                       String value)
                                throws JspException

Add an HTML state attribute to a AbstractHtmlState object. This method performs checks on common attributes and sets their values on the state object or throws an exception.

For the HTML tags it is not legal to set the id or name attributes. In addition, the base tag does not allow facets to be set. If the attribute is legal it will be added to the general expression map stored in the AbstractHtmlState of the tag.

Parameters:

state - the state object to which attributes are appliedn

name - the name of an attribute

value - the value of the attribute

Throws:

JspException - when an error occurs setting the attribute on the state object