Fetch all commands

What I want to do is to get all commands from all plugins installed, I've got it so far that I can get all the commands in object form, into a HashMap variable. How can I get the command usage, description, aliases and name (label) from here?

You should get the point out of this lines:

Code:

PluginDescriptionFile eHelpPDF;
HashMap<?, ?> eHelpCommands;

for (Plugin plugin : getServer().getPluginManager().getPlugins()) {
    eHelpPDF = plugin.getDescription();
    eHelpCommands = (HashMap<?, ?>) eHelpPDF.getCommands();
    // This is where it ends, but I can give you a little view of what I want
   for(String eHelpCommand : eHelpCommands.???) { ??? }
}

So, what am I missing for the last part?