DataTable & CheckBox

[Enrique Medina <e....@gmail.com>]

Hi,

Myabe this is a recurrent issue, but just to serve as a conclusion...

>From the posts I've found regarding the use of checkboxes inside a
DataTable, the most widely used approach would be to include a boolean
property in the JavaBean (eg. selected) that populates the DataTable,
so when anyone selects several checkboxes and clicks on a typical
button called "Delete selected", the following code gets executed:

public String deleteSelected() 
{
 
    // Iterate through the data rows ...
    int first = table.getFirst();
    int rows = table.getRows();
    for (int index = first; index < (first + rows); index++) {
 
        // Position the table at the current row ...
        table.setRowIndex(index);
 
        // And get the message bean for this row ...
        MyJavaBean javaBean = (MyJavaBean)
FacesContext.getCurrentInstance().getRequestMap().get("javaBean");
 
        // If this row is selected, delete the corresponding message
        if (javaBean.isSelected()) {
                ...
            }
 
        }

        table.setRowIndex(-1); // We're done now

        return (null); // Redisplay the current page
}

IMHO, this mixes presentation logic into your domain model, so it
shouldn't be recommended.

So, I was wondering whether there is a cleaner way to achieve this
needed behaviour. I remember when using Struts that I could give the
checkbox a value, which was the ID of my JavaBean:

<form>
<table>
    <tr>
        <td><input type="checkbox" id="chkItems" value="${myBean.id}"/></td>
        <td>MyBean 1</td>
    </tr>
    <tr>
        <td><input type="checkbox" id="chkItems" value="${myBean.id}"/></td>
        <td>MyBean 2</td>
    </tr>
    <tr>
        <td><input type="checkbox" id="chkItems" value="${myBean.id}"/></td>
        <td>MyBean 2</td>
    </tr>
</table>
<input type="submit" value="Delete Selected" />

So when I submitted the form, I could get through the request the
String[] parameter named "chkItems" where I had all the information I
needed to delete my objects...

I think there could be two nice solutions to this problem using MyFaces:

1) Extend the DataTable component to have a new attribute that would
render the checkbox and a new method to return all the checkboxes
selected

2) Create a new checkbox component that allow to bind a value distintc
to a boolean (or maybe just extend the selectBooleanCheckBox)

What dou you think? Are there any other good alternatives?

Re: DataTable & CheckBox

[Enrique Medina <e....@gmail.com>]

Still can't find any good solution? Any proposals?

2005/6/5, Enrique Medina <e....@gmail.com>:
> Hi,
> 
> Myabe this is a recurrent issue, but just to serve as a conclusion...
> 
> From the posts I've found regarding the use of checkboxes inside a
> DataTable, the most widely used approach would be to include a boolean
> property in the JavaBean (eg. selected) that populates the DataTable,
> so when anyone selects several checkboxes and clicks on a typical
> button called "Delete selected", the following code gets executed:
> 
> public String deleteSelected()
> {
> 
>     // Iterate through the data rows ...
>     int first = table.getFirst();
>     int rows = table.getRows();
>     for (int index = first; index < (first + rows); index++) {
> 
>         // Position the table at the current row ...
>         table.setRowIndex(index);
> 
>         // And get the message bean for this row ...
>         MyJavaBean javaBean = (MyJavaBean)
> FacesContext.getCurrentInstance().getRequestMap().get("javaBean");
> 
>         // If this row is selected, delete the corresponding message
>         if (javaBean.isSelected()) {
>                 ...
>             }
> 
>         }
> 
>         table.setRowIndex(-1); // We're done now
> 
>         return (null); // Redisplay the current page
> }
> 
> IMHO, this mixes presentation logic into your domain model, so it
> shouldn't be recommended.
> 
> So, I was wondering whether there is a cleaner way to achieve this
> needed behaviour. I remember when using Struts that I could give the
> checkbox a value, which was the ID of my JavaBean:
> 
> <form>
> <table>
>     <tr>
>         <td><input type="checkbox" id="chkItems" value="${myBean.id}"/></td>
>         <td>MyBean 1</td>
>     </tr>
>     <tr>
>         <td><input type="checkbox" id="chkItems" value="${myBean.id}"/></td>
>         <td>MyBean 2</td>
>     </tr>
>     <tr>
>         <td><input type="checkbox" id="chkItems" value="${myBean.id}"/></td>
>         <td>MyBean 2</td>
>     </tr>
> </table>
> <input type="submit" value="Delete Selected" />
> 
> So when I submitted the form, I could get through the request the
> String[] parameter named "chkItems" where I had all the information I
> needed to delete my objects...
> 
> I think there could be two nice solutions to this problem using MyFaces:
> 
> 1) Extend the DataTable component to have a new attribute that would
> render the checkbox and a new method to return all the checkboxes
> selected
> 
> 2) Create a new checkbox component that allow to bind a value distintc
> to a boolean (or maybe just extend the selectBooleanCheckBox)
> 
> What dou you think? Are there any other good alternatives?
>