Complex structure in JSTL

[Mike Higgins]

Hello everyone,

I have a difficult question about JSTL.

I have following strutures in my WebApp but I don't know how to
reterieve data from it using JSTL.

So first, I have a container class for data. Code snippet is below.
It contains different objects stored by key value.

public class UserResponse extends Hashtable
{
public UserResponse(){
}

// Getter
public Object getResponse(String key) {
return get(key);
}
// Setter
public void setResponse(String key, Object value) {
put(key, value);
}
}

Then I have a ordinary SessionBean like this
public class SessionInfoBean implements java.io.Serializable
{
private String SessionID;
private String RowRecord;
private String RowNumber;
...
and I read them from database and store them into an ArrayList.
like this way:

ArrayList SessionsList = new ArrayList();
while (rs.next())
{
SessionInfoBean sessionInfoBean = new SessionInfoBean();
sessionInfoBean.setSessionID(rs.getString("sessionid"));
sessionInfoBean.setRowNumber(Long.toString(rs.getLong("row_number")));
sessionInfoBean.setRowRecord(rs.getString("rowrecord"));
SessionsList.add(sessionInfoBean);
}

Then I store the ArrayList of SessionInfoBean intems into UserResponse object that is descripted in the beginning this message. Code look like this:

userResponse.setResponse(Constants.DATA_BY_ID, (Object) SessionsList);

The question is: Can I iterate all properties that are in ArrayList stored into SessionInfoBean items using JSTL?

Is this too complex or can it be resolved?
I have tried almost everytging that comes into my mind but not succeeded.
Can anyone give some "light" how to solve this with JSTL?

Thanks!

[Paul Clapham]

You can certainly iterate through an ArrayList in JSTL, since it's a List. And if your SessionInfoBean is a "well-formed" JavaBean, then you can access it in JSTL with no problem. I don't understand where the UserResponse object comes into the picture, though. But JSTL can access it too, since it's a Map.

To iterate through a List in JSTL:

<c:forEach var="session" items="${sessionlist}">

where "sessionlist" is the name of a session, request, or page variable that contains the List. To access something from the SessionInfoBean you just use its JavaBean properties:

${session.rowNumber}

for example. And to access a Map by its key in JSTL you do something like this:

${map[key]}

[Gene Winston]

Thanks Paul for answering!

I'm doing a small MVC based stuff and in my previous example
following code is little difficult to understand, because it has a parameter.

Usually, or what books shows beans contains strings having
only getter and setter methods like getSpeed or setSpeed
and you just reference them easily using e.g. "speed"
without any parameters. But when a Bean's member is a Collection
with key and you should ask first the proper Collection item and then it's
object properties, that makes me feeling fuzzy. Especilly when trying to use
JSTL.

// Getter that can return a collection
public Object getResponse(String key) {
return get(key);
}

[Bear Bibeault]

Gene, I'm not sure exactly what your question is. Please elaborate. Also in the future, please open your own topics with your question rather than tacking it onto someone else's.

A few points. If a method takes a parameter, it's not a "getter" (the proper term is actually "accessor"), it's just a method that doesn't follow the JavaBean standard.

For use with the EL, your classes must adhere to the bean standards.