Tuesday, 22 November 2011

ADF bug: missing af:column borders in af:table for IE7

There’s a rather obscure JDeveloper bug that only effects IE7, for af:columns in af:tables that show af:outputText fields based on dates that are null (phew, try and say that with a mouth full of wheaties). It occurs in and (and all versions in between it’s assumed).

In the previous picture from IE7 if you look closely, you’ll notice that the HireDate2 column has lost its border for the null entries. Note the other columns even when they are null, still have a border.

If we look under IE8 (or any other browser for that matter) we see the problem doesn’t occur at all:

The problem is being caused by 2 separate issues:

1) IE7 does not render borders for HTML table cells (ie. the tag) if the cell contains no data. This can be fixed if the cell contains a   tag.

2) ADF Faces RC includes the   tag for empty table cells, except for null date af:outputText fields who in addition have child tags that aren’t converter and validator tags.

To demonstrate the bug the MissingTableBorders application includes a simple test case. The application contains a View Object “EmployeesView” with a query based on the Oracle HR sample schema:
(CASE WHEN employee_id < 105 THEN first_name ELSE null END) AS FIRST_NAME1,
(CASE WHEN employee_id < 105 THEN first_name ELSE null END) AS FIRST_NAME2,
(CASE WHEN employee_id < 105 THEN hire_date ELSE null END) AS HIRE_DATE1,
(CASE WHEN employee_id < 105 THEN hire_date ELSE null END) AS HIRE_DATE2
The query is designed to return two String columns that will have a mix of null and non null values, and two date columns that will also have a mix of null and non null values. If we run the Business Components Browser the data appears as follows:

Next is the code for our JSPX page “Employees.jspx” containing an af:table based on the VO from above. I’ve deliberately cut out the surroundings tags to focus on the tags that matter:
emptyText="#{bindings.EmployeesView1.viewable ? 'No data.' : 'Access Denied.'}"
<af:outputText value="#{row.EmployeeId}" id="ot4">
<af:convertNumber groupingUsed="false" pattern="#{bindings.EmployeesView1.hints.EmployeeId.format}"/>
<af:outputText value="#{row.FirstName1}" id="ot5">
<af:outputText value="#{row.FirstName2}" id="ot2">
<af:clientAttribute name="ItemValue" value="#{row.FirstName2}"/>
<af:outputText value="#{row.HireDate1}" id="ot3">
<af:convertDateTime pattern="#{bindings.EmployeesView1.hints.HireDate1.format}"/>
<af:outputText value="#{row.HireDate2}" id="ot1">
<af:convertDateTime pattern="#{bindings.EmployeesView1.hints.HireDate2.format}"/>
<af:clientAttribute name="ItemValue" value="#{row.HireDate2}"/>
The code was created by JDeveloper by drag and dropping the VO from the data control palette, with the following changes:

a) There are two columns to display data from the first_name column. The only difference between them is the first_name2 column includes an additional af:clientAttribute tag.

b) There are two columns to display data from the hire_date column. Similar to the first_name columns, they only differ in the fact hire_date2 includes an af:clientAttribute tag.

When this page renders in the browser the generate HTML content for the rows of the table are as follows (note the formatting and the comment were added by me to make it easier to read):
<!-- ---------- Record 100 ---------- -->
<tr _afrrk="0" class="xxy ">
<td style="width:100px;" nowrap="" class="xxv"><nobr>100</nobr></td>
<td style="width:100px;" nowrap="" class="xxv"><nobr>Steven</nobr></td>
<td style="width:100px;" nowrap="" class="xxv"><nobr><span id="t1:0:ot2">Steven</span></nobr></td>
<td style="width:100px;" nowrap="" class="xxv"><nobr>17/06/1987</nobr></td>
<td style="width:100px;" nowrap="" class="xxv"><nobr><span id="t1:0:ot1">17/06/1987</span></nobr></td>
<!-- ---------- Record 101 ---------- -->
<tr _afrrk="1" class="xxy">
<td nowrap="" class="xxv"><nobr>101</nobr></td>
<td nowrap="" class="xxv"><nobr>Neena</nobr></td>
<td nowrap="" class="xxv"><nobr><span id="t1:1:ot2">Neena</span></nobr></td>
<td nowrap="" class="xxv"><nobr>21/09/1989</nobr></td>
<td nowrap="" class="xxv"><nobr><span id="t1:1:ot1">21/09/1989</span></nobr></td>
<!-- ---------- Record 102 ---------- -->
<tr _afrrk="2" class="xxy">
<td nowrap="" class="xxv"><nobr>102</nobr></td><td nowrap="" class="xxv"><nobr>Lex</nobr></td>
<td nowrap="" class="xxv"><nobr><span id="t1:2:ot2">Lex</span></nobr></td>
<td nowrap="" class="xxv"><nobr>13/01/1993</nobr></td>
<td nowrap="" class="xxv"><nobr><span id="t1:2:ot1">13/01/1993</span></nobr></td>
<!-- ---------- Record 103 ---------- -->
<tr _afrrk="3" class="xxy">
<td nowrap="" class="xxv"><nobr>103</nobr></td>
<td nowrap="" class="xxv"><nobr>Alexander</nobr></td>
<td nowrap="" class="xxv"><nobr><span id="t1:3:ot2">Alexander</span></nobr></td>
<td nowrap="" class="xxv"><nobr>3/01/1990</nobr></td>
<td nowrap="" class="xxv"><nobr><span id="t1:3:ot1">3/01/1990</span></nobr></td>
<!-- ---------- Record 104 ---------- -->
<tr _afrrk="4" class="xxy">
<td nowrap="" class="xxv"><nobr>104</nobr></td>
<td nowrap="" class="xxv"><nobr>Bruce</nobr></td>
<td nowrap="" class="xxv"><nobr><span id="t1:4:ot2" class="">Bruce</span></nobr></td>
<td nowrap="" class="xxv"><nobr>21/05/1991</nobr></td>
<td nowrap="" class="xxv"><nobr><span id="t1:4:ot1">21/05/1991</span></nobr></td>
<!-- ---------- Record 105 ---------- -->
<tr _afrrk="5" class="xxy"><td nowrap="" class="xxv"><nobr>105</nobr></td>
<td nowrap="" class="xxv"><nobr></nobr> </td>
<td nowrap="" class="xxv"><nobr><span id="t1:5:ot2"></span></nobr> </td>
<td nowrap="" class="xxv"><nobr></nobr> </td>
<td nowrap="" class="xxv"><nobr><span id="t1:5:ot1"></span></nobr></td>
<!-- ---------- Record 106 ---------- -->
<tr _afrrk="6" class="p_AFSelected p_AFFocused xxy">
<td nowrap="" class="xxv"><nobr>106</nobr></td><td nowrap="" class="xxv"><nobr></nobr> </td>
<td nowrap="" class="xxv"><nobr><span id="t1:6:ot2"></span></nobr> </td>
<td nowrap="" class="xxv"><nobr></nobr> </td>
<td nowrap="" class="xxv"><nobr><span id="t1:6:ot1"></span></nobr></td>
<!-- ---------- Record 107 ---------- -->
<tr _afrrk="7" class="xxy"><td nowrap="" class="xxv"><nobr>107</nobr></td>
<td nowrap="" class="xxv"><nobr></nobr> </td>
<td nowrap="" class="xxv"><nobr><span id="t1:7:ot2"></span></nobr> </td>
<td nowrap="" class="xxv"><nobr></nobr> </td>
<td nowrap="" class="xxv"><nobr><span id="t1:7:ot1"></span></nobr></td>
<!-- ---------- Record 108 ---------- -->
<tr _afrrk="8" class="xxy">
<td nowrap="" class="xxv"><nobr>108</nobr></td>
<td nowrap="" class="xxv"><nobr></nobr> </td>
<td nowrap="" class="xxv"><nobr><span id="t1:8:ot2"></span></nobr> </td>
<td nowrap="" class="xxv"><nobr></nobr> </td>
<td nowrap="" class="xxv"><nobr><span id="t1:8:ot1"></span></nobr></td>
<!-- ---------- Record 109 ---------- -->
<tr _afrrk="9" class="xxy">
<td nowrap="" class="xxv"><nobr>109</nobr></td>
<td nowrap="" class="xxv"><nobr></nobr> </td>
<td nowrap="" class="xxv"><nobr><span id="t1:9:ot2"></span></nobr> </td>
<td nowrap="" class="xxv"><nobr></nobr> </td>
<td nowrap="" class="xxv"><nobr><span id="t1:9:ot1"></span></nobr></td>
<!-- ---------- Record 110 ---------- -->
<tr _afrrk="10" class="xxy">
<td nowrap="" class="xxv"><nobr>110</nobr></td>
<td nowrap="" class="xxv"><nobr></nobr> </td>
<td nowrap="" class="xxv"><nobr><span id="t1:10:ot2"></span></nobr> </td>
<td nowrap="" class="xxv"><nobr></nobr> </td>
<td nowrap="" class="xxv"><nobr><span id="t1:10:ot1"></span></nobr></td>
If you look at records 100 to 104 all columns include data.

If we look at records 105 to 110 note:

a) The FirstName1 column when null includes a &nbsp; to forcefully place a blank entry into the cell.

b) The FirstName2 column does exactly the same, remembering the FirstName2 column includes an additional af:clientAttribute tag.

c) For the HireDate1 column it also includes a &nbsp;. Remember the HireDate1 column *does*not* include an af:clientAttribute tag.

d) For the HireDate2 column it *does*not* include an &nbsp; tag, even though the HireDate2 values are null. Remember the HireDate2 column *does*include* an af:clientAttribute tag.

At this point we only see differing behaviour with af:outputText values in af:columns where they show Dates *and* the af:outputText includes an af:clientAttribute tag.

From my testing, converter and validator tags added to the af:outputText don't exhibit the same behaviour. However any other tag, not just adding an af:clientAttribute tag but even an af:clientListener as example will result in the missing &nbsp; tag.

This in itself isn't an issue but when we consider IE7. If you render this page in IE8 the null date columns with an af:clientAttribute tag will still show the cell borders:

Yet in IE7 we get this:

While the issue is particular to IE7, the issue could be fixed by ADF Faces RC consistently generating the &nbsp; entry as described in the HTML generated above.

In discussing this bug (12942411) with Oracle staff it turns out there is a broader base bug 9682969 where this issue occurs for more than just date columns. Unfortunately the problem is not easily fixable by Oracle as it requires the af:table and af:column components to know if the child component (in this example an af:outputText) will be null before it and the data it refers to is accessed and rendered.

The simple workaround as proposed by Oracle is to not render the child component at all if the data value is null, simply by including code similar to the following:
My thanks to Oracle staff who assisted in looking and resolving this issue.

A sample application can be downloaded from here.

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