Viewing Task Attachments

This post relates to the custom BPM worklist sample presented in this blog.

In this post, we will look at how to add support for viewing a list of the attachments for a Human Task.

You may recall from the post on creating the domain layer that we created a wrapper to simplify access to the Human Task object.  In that wrapper class, com.oracle.ateam.domain.MTask, we had a property called attachments which is a java.util.List of the attachments.

Attachments are represented by the BPM API class oracle.bpel.services.workflow.task.model.Attachment (see Javadoc here.)

We can add the following code into our view, src/main/webapp/WEB-INF/jsp/taskdetails.jsp, to display information about each attachment.  Here we are displaying three pieces of information about each attachment:

• ${attachment.updatedBy} is the user who last updated (or created) the attachment,
• ${attachment.updatedDate.time} is the time the attachment was last updated (or created), and
• ${attachment.name} is the name of the attachment, most likely this would be the filename, although attachments can also be URLs rather than files.

We also want to display a link to allow the user to download the attachment.  We are making the name into the link.  The link is constructed as follows:

downloadattachment.do?x_tasknumber=${model.task.number}&x_file=${attachment.name}&x_version=${attachment.version}

We are passing the task number, the attachment name and version to a new  downloadattachment controller.  We will see this controller in the next post.

Here is the code we added to the view:

  <h2>Attachments</h2>
  <table width="50%">
    <tr>
      <th class="tl-head" width="150">User</th>
      <th class="tl-head" width="200">Date</th>
      <th class="th-head">Name</th>
    </tr>
  </table>
  <table width="50%">
    <c:forEach items="${model.task.attachments}" var="attachment">
      <tr>
        <td class="tl-row" width="150">${attachment.updatedBy}</td>
        <td class="tl-row" width="200">${attachment.updatedDate.time}</td>
        <td class="tl-row">
          <a href="downloadattachment.do?x_tasknumber=${model.task.number}&x_file=${attachment.name}&x_version=${attachment.version}"
             target="_blank">${attachment.name}</a>
        </td>
      </tr>
    </c:forEach>
  </table>

That’s all we need to view a list of the attachments!  In the next post we will look at how to allow the user to download (open/save) an attachment.