How to print list of Files?

[Gopu Akraju]

I have a list of Files. I would like to print their names. I tried as below:
But I get an exception as below: Can anyone tel me what the problem is?

  
private void createCheckBoxes(List javaFiles) {
        int count = javaFiles.size();
        System.out.println("The number of files are"+count);
        
        Iterator it = javaFiles.iterator() ;
        while  ( it.hasNext()){
            String s = (String)it.next() ;
            System.out.println(s);
        }
 

  

  
Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: java.io.File
        at extraction.Extract.createCheckBoxes(Extract.java:190)
        at extraction.Extract.actionPerformed(Extract.java:161)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1849)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2169)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
        at java.awt.Component.processMouseEvent(Component.java:5488)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3126)
        at java.awt.Component.processEvent(Component.java:5253)
        at java.awt.Container.processEvent(Container.java:1966)
        at java.awt.Component.dispatchEventImpl(Component.java:3955)
        at java.awt.Container.dispatchEventImpl(Container.java:2024)
        at java.awt.Component.dispatchEvent(Component.java:3803)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4212)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3892)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3822)
        at java.awt.Container.dispatchEventImpl(Container.java:2010)
        at java.awt.Window.dispatchEventImpl(Window.java:1778)
        at java.awt.Component.dispatchEvent(Component.java:3803)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:463)
        at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:242)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:163)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:157)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:149)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java
  

[Ulf Dittmer]

You can't cast a File to a String. Something like "System.out.println(((File) it.next).getName())" should do the trick.

[Campbell Ritchie]

Probably better however to use a parametrised Iterator.

. . .
Iterator<File> it = javaFiles.iterator();
. . .
System.out.println(it.next().getName());

That way you can dispense with the class casting.

[Gopu Akraju]

Thanks for the tricky answer. I am able to print the name of the file.
But I have to store the file name in a string then start manupulating that. How do I do that? Thanks.

[Ulf Dittmer]

"((File) it.next).getName()" is the file name as a string. What else are you looking for?

[S Keith]

Heres some code that should explain things.

I've tried to keep it similar to the code you gave.

import java.util.*;
import java.io.*;
 
class Test{
 
        public static void main(String [] args){
ArrayList<File> foo = new ArrayList<File>();
foo.add(new File("bob"));
new Test().createCheckBoxes(foo);
}
 
private void createCheckBoxes(List<File> javaFiles) {
int count = javaFiles.size();     
  
Iterator<File> it = javaFiles.iterator() ;
while  ( it.hasNext()){
String s = (it.next()).getName() ;  
// use some string functions 
System.out.println(s + " in upper case is " + s.toUpperCase());
System.out.println(s + " is " + s.length() + " characters long");
}
}
}

running this gives:

 
C:\Users\Steven\Desktop>javac Test.java
 
C:\Users\Steven\Desktop>java Test
bob in upper case is BOB
bob is 3 characters long
 
C:\Users\Steven\Desktop>

http://java.sun.com/javase/6/docs/api/java/lang/String.html