Java - ArrayList of Modules - how do I

list all modules in the ArraryList? -

I thought it'd be something like below but this won't compile (error - cannot find symbol - method list).

/**
 * This method lists all modules in the ArrayList
 */
public String listAllModules()
{
    return modules.list();
}

Thanks. (new to Java in case that isn't obvious.开发者_如何转开发.)

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The method list() isn't available for ArrayList. Use a for loop instead:

for (Module m: modules) {
   System.out.println(m);
}

Assuming that the ArrayList modules has objects with the type of Module

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For a String List of your List Elements you can override the toString Method to fit your needs.

and then like

public String listAllModules()
{
    return modules.toString();
}

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Do you just need to iterate through a List? Try this:

for (Object o : modules) {
    // do something with each object from the list
}

Hard to understand what you're trying to do without more information.

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Depending on what you have, you might want to try out the toString() method. If you want something more customizable, you can do something like this:

public String listAllModules()
{
   StringBuilder str = new StringBuilder();
   for (int i = 0; i < modules.size(); i++)
   {
     str.append(modules.get(i));  // you can append any other data here
   }

   return str.toString();
}

You can take a look at the ArrayList api or more information. In the above code, I am assuming that ArrayList modules is an arraylist of strings, ie: ArrayList modules.

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I am unclear about the type of 'modules' variable. If it is array then you can simply use, Arrays.asList(modules);