How to handle better data from HashMap in Java?

How to handle better data from HashMap in Java?

In order to develop a text editor in Java, the user is able to open
several files with a object JTabbedPane. Then, I stores such files on
HashMap<String,TabManager>. (The key of the HashMap), should to be the
name of the file. After, I have on memory the files opened within of
HashMap. Now, I need manage my tabs. For example, if the user is on tab
selected by it, is evident that the user would like to change the font of
the text, save file selected, copy it, and so on. For manage the tab
selected by the user, I need of a class to get just the objects from tab
selected, just. Such as, JTextPane and File. Basically, I should do:
for(Map.Entry<String, TabManager> entry: HashMap.entry)
{
String key = entry.getKey();
tabManager = entry.getValue();
if(tab.getTabSelected().equals(key))
{
// resquest objects from tab selected by the user
this.container = tabManager.getJTextPane();
this.file = tabManager.getFile();
}
}
I have on my hands the objects from tab selected by the user. Now, I going
to handle it. The issue is:
How I handle that big amount of datas ?
All time, I have that do the loop to know which tab the user is selected ?
How I handle this data ?