String imageClicked = null;
Enumeration enum = request.getParameterNames();
String parameterName = null;
while(enum.hasMoreElements()) {
parameterName = (String)enum.nextElement();
if(parameterName.endsWith(".x")) {
imageClicked = parameterName.substring(0,parameterName.indexOf('.'));
}
}
return imageClicked;
That's all there is to it. Your button solution is too complicated in any event. The better button solution involves making only one button and then nuking that button as soon as you determine what image was clicked. I just nuked the whole solution, since it is unnecessary.
Michael
Janne Mattila wrote:
I described what I wanted to achieve in my original posting. To recap, I want to have a page with several delete buttons. Clicking on one button would produce parameter
delete_23.x=56
to be sent => we parse that, and delete item with ID 23 from database. Choosing a different delete -button would send parameter
delete_304.x=144
=> we delete item with ID 304.
I am aware that I can use the approach you suggested (parse request parameters manually), and have been doing that for ages before I started learning Struts :) I was just expecting that Struts would somehow help me with this task. I have been looking into indexed properties but I have not quite figured out how to properly implement this kind of functionality using them.
I finally figured out a reasonably satisfying way to do this while using Struts to help as much as possible:
public class ChoicesForm extends ActionForm {
private Collection choices; private ImageButtonTracer deleteButton;
public void reset(ActionMapping arg0, HttpServletRequest arg1) { this.choices = new ArrayList(); this.deleteButton = new ImageButtonTracer(); }
public ChoiceView getChoice(int index) { // if struts tries to get item with id index, // and it does not exist, // add new items until ok. while (choices.size() <= index) { choices.add(new ChoiceView()); } List lChoices = (List) choices; return (ChoiceView) lChoices.get(index); }
public Collection getChoices() { return choices; } public void setChoices(Collection collection) { choices = collection; } public ImageButtonTracer getDeleteButton() { return deleteButton; } public void setDeleteButton(ImageButtonTracer tracer) { deleteButton = tracer; } }
public class ImageButtonTracer { private Map clickedButtons;
public ImageButtonTracer() { clickedButtons = new HashMap(); }
public Button getItem(int index) {
Button toReturn = (Button) clickedButtons.get(new Integer(index));
if (toReturn == null) toReturn = new Button();
clickedButtons.put(new Integer(index), toReturn);
return toReturn;
}
public void setItem(int index, Button button) { logger.debug("setItem(" + index + ")"); clickedButtons.put(new Integer(index), button); }
public Collection getClickedButtonIndexes() { return clickedButtons.keySet(); }
public class Button { private int x; private int y;
public int getX() { return x; } public int getY() { return y; } public void setX(int i) { x = i; } public void setY(int i) { y = i; } } }
public class ChoiceView implements Serializable { private String key; private String name; private String description;
... + getters & setters }
<html:form action="/SaveChoices" method="GET">
<table border=1>
<logic:iterate id="choice" name="choicesForm" property="choices">
<tr>
<td><bean:write name="choice" property="key"/><html:hidden indexed="true" name="choice" property="key"/></td>
<td><html:text indexed="true" name="choice" property="name"/></td>
<td><html:text indexed="true" name="choice" property="description"/></td>
<td><html:image indexed="true" src="delete.gif" property="deleteButton.item"/></td>
</tr>
</logic:iterate>
</table>
<br><html:submit/>
</html:form>
public class SaveChoicesAction extends Action { public ActionForward execute( ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception { ChoicesForm cform = (ChoicesForm) form;
ChoiceDAO dao = new ChoiceDAO(); // UPDATE Iterator i = cform.getChoices().iterator(); while (i.hasNext()) { ChoiceView view = (ChoiceView) i.next(); Choice toUpdate = ChoiceView.createChoice(view); dao.update(toUpdate); }
// DELETE Collection deletedIds = cform.getDeleteButton().getClickedButtonIndexes(); if (deletedIds != null) { Iterator d = deletedIds.iterator(); while (d.hasNext()) { int deleteIndex = ((Integer) d.next()).intValue(); ChoiceView toDelete = cform.getChoice(deleteIndex); Choice choice = ChoiceView.createChoice(toDelete); dao.delete(choice); } } return mapping.findForward("success"); } }
ImageButtonTracer can be simplified a bit if one assumes that only one button can be clicked per request (as is the case) => public Collection getClickedButtonIndexes() can be changed to public int getClickedButtonIndex(). This works, and I can use indexed properties somewhat comfortably.
Any improvements / alternatives are welcome.
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