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

java.lang.Object
  javax.servlet.jsp.tagext.TagSupport
      javax.servlet.jsp.tagext.BodyTagSupport
          com.bea.wlw.netui.tags.AbstractBaseTag
              com.bea.wlw.netui.tags.databinding.base.StructuredBaseTag
                  com.bea.wlw.netui.tags.databinding.grid.GridComponent
                      com.bea.wlw.netui.tags.databinding.grid.column.GridColumn
                          com.bea.wlw.netui.tags.databinding.grid.column.FormattableColumn
                              com.bea.wlw.netui.tags.databinding.grid.column.ExpressionColumn

All Implemented Interfaces:

Formattable, HtmlConstants, Serializable, javax.servlet.jsp.tagext.BodyTag, javax.servlet.jsp.tagext.IterationTag, javax.servlet.jsp.tagext.JspTag, javax.servlet.jsp.tagext.Tag

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
Attribute	Required	Runtime Expression Evaluation	Data Bindable
title	No	No	No
	The text that will be rendered in the header for this column.
value	No	No	Yes
	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.

See Also:

Grid, Serialized Form

Example:

Given a data item that has a lastName field and a firstName field, the following would render these together in a single cell:

    <netui-data:expessionColumn value="{container.item.lastName},
         {container.item.firstName}"
         title="Last Name, First Name"
         />

Sample Code

[BEA_HOME]/weblogic81/samples/workshop/SamplesApp/WebApp/tagSamples/netui_databinding/grid/grid.jsp

Beadoc.tagdescription:

A column that can use data binding expressions to determine 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.

Field Summary

Fields inherited from class com.bea.wlw.netui.tags.databinding.base.StructuredBaseTag

EMPTY_STRING

Fields inherited from class com.bea.wlw.netui.tags.AbstractBaseTag

ATTR_GENERAL, ATTR_GENERAL_EXPRESSION, ATTR_JAVASCRIPT, ATTR_STYLE, JAVASCRIPT_STATUS, NETUI_UNIQUE_CNT

Fields inherited from class javax.servlet.jsp.tagext.BodyTagSupport

bodyContent

Fields inherited from class javax.servlet.jsp.tagext.TagSupport

id, pageContext

Fields inherited from interface com.bea.wlw.netui.tags.html.HtmlConstants

ACCEPT, ACCESSKEY, ACTION, ALIGN, ALINK, ALT, ANCHOR, BACKGROUND, BASE, BGCOLOR, BODY, BORDER, BR, CAPTION, CELLPADDING, CELLSPACING, CHAR, CHAROFF, CHARSET, CHECKED, CLASS, COLS, COORDS, DIR, DISABLED, DIV, ENCTYPE, FOR, FORM, FORM_GET, FORM_POST, FRAME, HEIGHT, HREF, HREFLANG, HSPACE, HTML, ID, IMAGE, INPUT, INPUT_BUTTON, INPUT_CHECKBOX, INPUT_FILE, INPUT_HIDDEN, INPUT_IMAGE, INPUT_PASSWORD, INPUT_RADIO, INPUT_RESET, INPUT_SUBMIT, INPUT_TEXT, ISMAP, LABEL, LANG, LINK, LONGDESC, MAXLENGTH, METHOD, NAME, ONBLUR, ONCHANGE, ONCLICK, ONDBLCLICK, ONFOCUS, ONKEYDOWN, ONKEYPRESS, ONKEYUP, ONLOAD, ONMOUSEDOWN, ONMOUSEMOVE, ONMOUSEOUT, ONMOUSEOVER, ONMOUSEUP, ONRESET, ONSELECT, ONSUBMIT, ONUNLOAD, OPTION, READONLY, REL, REV, ROWS, RULES, SELECT, SHAPE, SIZE, SPAN, SRC, STYLE, SUMMARY, TABINDEX, TABLE, TARGET, TD, TEXT, TEXTAREA, TITLE, TR, TYPE, USEMAP, VALIGN, VALUE, VLINK, VSPACE, WIDTH

Fields inherited from interface javax.servlet.jsp.tagext.BodyTag

EVAL_BODY_BUFFERED, EVAL_BODY_TAG

Fields inherited from interface javax.servlet.jsp.tagext.IterationTag

EVAL_BODY_AGAIN

Fields inherited from interface javax.servlet.jsp.tagext.Tag

EVAL_BODY_INCLUDE, EVAL_PAGE, SKIP_BODY, SKIP_PAGE

Constructor Summary

ExpressionColumn()

Method Summary

String	getTagName() Get the name of this tag.
String	getTitle() Get the title rendered in the header cell of this column.
String	getValue() Get the value of this tag.
protected void	localRelease() Reset all of the fields of this tag.
String	renderDataCell() Render a cell for the "current" data item.
String	renderFooterCell() Render the footer.
String	renderHeaderCell() Render the header cell for this column.
void	setTitle(String title) Set the title rendered in the header cell of this column.
void	setValue(String value) Set the value of this tag.

Methods inherited from class com.bea.wlw.netui.tags.databinding.grid.column.FormattableColumn

addFormatter, format, renderStartTag

Methods inherited from class com.bea.wlw.netui.tags.databinding.grid.column.GridColumn

getColumns, getStyleClassPrefix, getValidContainerType, prepare, renderCloseCellTag, renderDataCellTag, renderEndTag, renderFooterCellTag, renderHeaderCellTag, renderOpenCellTag, setStyleClassPrefix

Methods inherited from class com.bea.wlw.netui.tags.databinding.grid.GridComponent

getCurrentRenderState, getGrid, getGridContext

Methods inherited from class com.bea.wlw.netui.tags.databinding.base.StructuredBaseTag

addContent, doEndTag, doStartTag, getContent, verifyAttributes, verifyStructure

Methods inherited from class com.bea.wlw.netui.tags.AbstractBaseTag

addTagIdMapping, containsExpression, evaluateAttributeToString, evaluateExpression, filter, filter, formatErrorString, formatString, getAttribute, getErrorsReport, getExpressionEvaluator, getJavaScriptUtils, getNearestForm, getNextId, getQualifiedBundleName, getScriptReporter, getUserLocale, hasErrors, isExpression, prepForRendering, registerAttribute, registerError, registerTagError, release, removeAttribute, renderAttribute, renderAttributes, reportErrors, rewriteName, setPageContext, updateExpression, write

Methods inherited from class javax.servlet.jsp.tagext.BodyTagSupport

doAfterBody, doInitBody, getBodyContent, getPreviousOut, setBodyContent

Methods inherited from class javax.servlet.jsp.tagext.TagSupport

findAncestorWithClass, getId, getParent, getValue, getValues, removeValue, setId, setParent, setValue

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface javax.servlet.jsp.tagext.Tag

getParent, setParent

Constructor Detail

ExpressionColumn

public ExpressionColumn()

Method Detail

getTagName

public String getTagName()

Get the name of this tag. This is used to identify the type of this tag for reporting tag errors.

Specified by:

getTagName in class AbstractBaseTag

Returns:

a constant String representing the name of this tag.

setTitle

public void setTitle(String title)

Set the title rendered in the header cell of this column.

Parameters:

title - the title of the column

Beadoc.attributedescription:

The text to render in the column header.

Beadoc.attributesyntaxvalue:

string_title

Beadoc.databindable:

false

getTitle

public String getTitle()

Get the title rendered in the header cell of this column.

Returns:

the title of the colum

setValue

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).

Beadoc.attributedescription:

The value may contain an expression(s) that will be evaluated before the data for each item in the <netui-data:grid>'s data set is rendered. The databinding expression {container.item} may be used to access the current data item that is being rendered.

Beadoc.attributesyntaxvalue:

string_or_expression_value

Beadoc.databindable:

true

getValue

public String getValue()

Get the value of this tag.

Returns:

the value of this tag

renderHeaderCell

public String renderHeaderCell()

Render the header cell for this column. The title attribute is rendered in the header of an ExpressionColumn.

Specified by:

renderHeaderCell in class GridColumn

Returns:

the String content that should be buffered for this tag

renderDataCell

public String renderDataCell()
                      throws javax.servlet.jsp.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.

Specified by:

renderDataCell in class GridColumn

Returns:

the String content that should be buffered for this tag

Throws:

javax.servlet.jsp.JspException - if an error occurs that can not be reported in the page

renderFooterCell

public String renderFooterCell()

Render the footer. This footer contains no text.

Specified by:

renderFooterCell in class GridColumn

Returns:

the emtpy string

localRelease

protected void localRelease()

Reset all of the fields of this tag.

Overrides:

localRelease in class FormattableColumn