Re: Processing multiple records all at once

[V. Cekvenich]

This is good.

However.... a bit much copying. Also, quite a few forms could have multi row processing or master/detail processing. One does not want to to it over and over; if you do OO, you could create a basebean that does this in the ancestor, by having your formbean implement a collection, as in basicPortal.com open source example.

.V

Max Cooper wrote:

Brad,

I have written some pages/actions that do what you describe here. I believe
that one way to go would be to use nested properties, but I haven't tried
that yet, so I am not sure how to do it. The solution I used was to create
an ActionForm for the page that has arrays for each field from the rows.
Something like this (generic example -- replace rowId and rowProperty1 with
your real row properties):

public class RowsForm extends ActionForm {
   private String[] rowId;
   private String[] rowProperty1;
   public String[] getRowId() {
      return rowId;
   }
   public void setRowId(String[] rowId) {
      this.rowId = rowId;
   }
   public String[] getRowProperty1() {
      return rowProperty1;
   }
   public void setRowProperty1(String[] rowProperty1) {
      this.rowProperty1 = rowProperty1;
   }
}

The properties are arrays to receive values from each row in the data set
when you submit the form. For iterating through the data, we added a method
that would return a Collection of objects, where each represents a single
row. Something like this:

public class RowForm extends ActionForm { // this could also be a plain-old
JavaBean, too
   private String id;
   private String property1;
   // getters and setters for the id and property1
}

// add this method to RowsForm
   public Collection getRows() {
      Collection rows = new ArrayList();
      final int size = rowId.length;
      for (int i = 0; i < size; i++) {
         RowForm row = new RowForm();
         row.setId(rowId[i]);
         row.setProperty1(rowProperty1[i]);
         rows.add(row);
      }
      return rows;
   }

So, that setup will allow you to get the data out of the form after the user
submits their changes (by calling RowsForm.getRows()). You will get data for
each row, so you still need to decide which rows were changed, and which
ones the user simply left alone.

As for getting the data into the form and displaying it on the page, you
could add another method like populateForm(Vector rowData) to copy the data
to the arrays like this:

// another method in RowsForm
   public void populateForm(Vector rowData) {
      // get the Vector size
      final int size = rowData.size();
      // initialize the arrays
      rowId = new String[size];
      rowProperty1 = new String[size];
      // copy the data from the objects in the Vector into the arrays
      Vector rowData = new Vector();
      final int size = rowData.size();
      Enumeration enum = rowData.elements();
      for (int i = 0; i < size; i++) {
         Data element = (Data) enum.nextElement();
         rowId[i] = String.valueOf(element.getId());
         rowProperty1[i] = element.getProperty1();
      }
   }

However, it might be a bit wasteful to copy all the data into the arrays if
you are going to call getRows() to turn them back into a Collection of
objects so that you can use the <logic:iterate> tag to display them in the
JSP. If you can get the data into a Collection instead of a Vector (or is a
Vector a Collection these days?), you can just have a single Collection
property on RowsForm that you set in the action, and the JSP will call the
getter to get the Collection to iterate over. The JSP to iterate over the
Collection and write out the rows might look something like this:

<table>
<tr>
  <th>id</th>
  <th>property1</th>
</tr>
<logic:iterate name="rowsForm" property="rows" id="row"
type="com.yada.yada.yada.RowForm" scope="request">
<tr>
  <td>
    <%-- write the id as text for display, and also as a hidden field for
submittal --%>
    <bean:write name="row" property="id" />
    <html:hidden name="row" property="id" />
  </td>
  <td>
    <html:text name="row" property="property1" />
  </td>
</tr>
</logic:iterate>
</table>

Your Action will get the populated RowsForm on the submit, and you can call
RowsForm.getRows() to get a Collection of RowForm objects to work with.

-Max

----- Original Message -----
From: "Brad Balmer" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, December 11, 2002 5:44 PM
Subject: Processing multiple records all at once

I've searched the internet and different news groups for an answer to this
question, but have yet to find something that matches what I'm trying to

do.

I have an application that reads records from a table and creates an
instance of a bean for each row.  Therefore, when I return from my DB

call,

I have a Vector of beans representing the data.

I need to display all of this on one jsp form, letting the user have the
ability to update any of the fields in any of the records and click a

Update

button, which will send ALL of the data back to the Action class to be
processed.  I have done this before (not using Struts), but we have

switched

our Architecture and need to re-implement.

Any help would be GREATLY appreciated.





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