ExpressionColumn Class

com.bea.wlw.netui.tags.databinding.grid.column
ExpressionColumn Class

public class ExpressionColumn

    extends FormattableColumn

A column that can use expressions in addition to formatters to format the value of a data cell. The expression column enables combining data from different fields of the current data item or even from different expression contexts into a value for the cell. An expression column is not sortable or filterable.

Attribute Descriptions
AttributeRequiredRuntime Expression EvaluationData Bindable
titleNoNoNo
The text that will be rendered in the header for this column.
valueNoNoYes
The expression value that can contain expressions that reference data in the current data item. The result of the expression evaluation will be rendered in the data cell.

Related Topics

Grid


Hierarchy
Object
  TagSupport
    BodyTagSupport
      AbstractBaseTag
        StructuredBaseTag
          GridComponent
            GridColumn
              FormattableColumn
                ExpressionColumn
All Implemented Interfaces

BodyTag, Formattable, IterationTag, Serializable, Tag

Field Summary

   
Fields from  com.bea.wlw.netui.tags.databinding.base.StructuredBaseTag
EMPTY_STRING
 
Fields from  com.bea.wlw.netui.tags.AbstractBaseTag
ATTR_GENERAL, ATTR_GENERAL_EXPRESSION, ATTR_JAVASCRIPT, ATTR_STYLE, CLASS, ID, JAVASCRIPT_STATUS, NAME, NETUI_UNIQUE_CNT, ONCLICK, ONDBLCLICK, ONKEYDOWN, ONKEYPRESS, ONKEYUP, ONMOUSEDOWN, ONMOUSEMOVE, ONMOUSEOUT, ONMOUSEOVER, ONMOUSEUP, STYLE, TABINDEX
 
Fields from  javax.servlet.jsp.tagext.BodyTagSupport
bodyContent
 
Fields from  javax.servlet.jsp.tagext.TagSupport
id, pageContext
 
Fields from interface javax.servlet.jsp.tagext.BodyTag
EVAL_BODY_BUFFERED, EVAL_BODY_TAG
 
Fields from interface javax.servlet.jsp.tagext.IterationTag
EVAL_BODY_AGAIN
 
Fields from interface javax.servlet.jsp.tagext.Tag
EVAL_BODY_INCLUDE, EVAL_PAGE, SKIP_BODY, SKIP_PAGE
 

Constructor Summary

ExpressionColumn()

 

Method Summary

public String
getTagName()
Get the name of this tag.
public String
getTitle()
Get the title rendered in the header cell of this column.
public String
getValue()
Get the value of this tag.
protected void
localRelease()
Reset all of the fields of this tag.
public String
renderDataCell()
Render a cell for the "current" data item.
public String
renderFooterCell()
Render the footer.
public String
renderHeaderCell()
Render the header cell for this column.
public void
setTitle(String title)
Set the title rendered in the header cell of this column.
public void
setValue(String value)
Set the value of this tag.
 
Methods from  com.bea.wlw.netui.tags.databinding.grid.column.FormattableColumn
addFormatter, format, renderStartTag
 
Methods from  com.bea.wlw.netui.tags.databinding.grid.column.GridColumn
getColumns, getStyleClassPrefix, getValidContainerType, localRelease, prepare, renderCloseCellTag, renderDataCellTag, renderEndTag, renderFooterCellTag, renderHeaderCellTag, renderOpenCellTag, renderStartTag, setStyleClassPrefix
 
Methods from  com.bea.wlw.netui.tags.databinding.grid.GridComponent
getCurrentRenderState, getGrid, getGridContext, getValidContainerType, localRelease, prepare
 
Methods from  com.bea.wlw.netui.tags.databinding.base.StructuredBaseTag
addContent, doEndTag, doStartTag, getContent, getCurrentRenderState, getValidContainerType, localRelease, prepare, renderEndTag, renderStartTag, verifyAttributes, verifyStructure
 
Methods from  com.bea.wlw.netui.tags.AbstractBaseTag
addTagIdMapping, evaluateAttributeToString, filter, filter, getJavaScriptUtils, getNearestForm, getScriptReporter, getUserLocale, localRelease, registerTagError, release, renderAttribute, rewriteName, write
 
Methods from  javax.servlet.jsp.tagext.BodyTagSupport
doAfterBody, doEndTag, doInitBody, doStartTag, getBodyContent, getPreviousOut, release, setBodyContent
 
Methods from  javax.servlet.jsp.tagext.TagSupport
doAfterBody, doEndTag, doStartTag, findAncestorWithClass, getId, getParent, getValue, getValues, release, removeValue, setId, setPageContext, setParent, setValue
 
Methods from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
   
Methods from interface javax.servlet.jsp.tagext.BodyTag
doInitBody, setBodyContent
 
Methods from interface com.bea.wlw.netui.tags.html.Formattable
addFormatter
 
Methods from interface javax.servlet.jsp.tagext.IterationTag
doAfterBody
 
Methods from interface javax.servlet.jsp.tagext.Tag
doEndTag, doStartTag, getParent, release, setPageContext, setParent
 

Constructor Detail

ExpressionColumn

public ExpressionColumn()
 

Method Detail

getTagName() Method

public String getTagName()
Get the name of this tag. This is used to identify the type of this tag for reporting tag errors.

Overrides
AbstractBaseTag.getTagName()

Returns

a constant String representing the name of this tag.

getTitle() Method

public String getTitle()
Get the title rendered in the header cell of this column.

Returns

the title of the colum

getValue() Method

public String getValue()
Get the value of this tag.

Returns

the value of this tag

localRelease() Method

protected void localRelease()
Reset all of the fields of this tag.

Overrides
FormattableColumn.localRelease()

renderDataCell() Method

public String renderDataCell()
throws JspException
Render a cell for the "current" data item. The value attribute is first evaluated as an expression, then formatted using any contained Formatter tags, and is finally returned to be buffered. If errors occur during the process of expression evaluation on the value attribute, these errors are reported in the page.

Overrides
GridColumn.renderDataCell()

Returns

the String content that should be buffered for this tag

Exceptions

JspException
if an error occurs that can not be reported in the page

renderFooterCell() Method

public String renderFooterCell()
Render the footer. This footer contains no text.

Overrides
GridColumn.renderFooterCell()

Returns

the emtpy string

renderHeaderCell() Method

public String renderHeaderCell()
Render the header cell for this column. The title attribute is rendered in the header of an ExpressionColumn.

Overrides
GridColumn.renderHeaderCell()

Returns

the String content that should be buffered for this tag

setTitle(String) Method

public void setTitle(String title)
Set the title rendered in the header cell of this column.

Parameters

title
the title of the column

setValue(String) Method

public void setValue(String value)
Set the value of this tag. The value may contain an expression(s) that will be evaluated before the data for each item in the Grid's data set is rendered. The databinding expression container may be used to access the "current" data item that is being rendered. For example, the expression container.item accesses the current data item.

Parameters

value
the value of this tag. This attribute may contain expression(s).