Example: Using the IFSFile listFiles() method to list the contents of a directory

//////////////////////////////////////////////////////////////////////////////////
//
// IFSListFiles example.  This program uses the integrated file system 
// classes to list the contents of a directory on the server.
//
// Command syntax:
//    IFSListFiles system directory
//
// For example,
//    IFSListFiles MySystem /path1 
//
//////////////////////////////////////////////////////////////////////////////////

import java.io.*;
import java.util.*;
import com.ibm.as400.access.*;

public class IFSListFiles extends Object
{
    public static void main(String[] parameters)
    {
        System.out.println( " " );

        String directoryName = "";
        String system        = "";


        // if both parameters were not specified, display help text and exit.

        if (parameters.length >= 2)
        {

            // Assume the first parameter is the system name and
            // the second parameter is the directory name

            system = parameters[0];
            directoryName = parameters[1];

            try
            {
                // Create an AS400 object for the server that holds the files.

                AS400 as400 = new AS400(system);



                // Create the IFSFile object for the directory.

                IFSFile directory = new IFSFile(as400, directoryName);


                // Generate a list of IFSFiles.  Pass the listFiles method 
                // the directory filter object and the search match          
                // criteria.  This method caches attribute information.  For 
                // instance, when isDirectory() is called on an IFSFile
                // object in the file array returned in the following code, 
                // no call to the server is required.
                //
                // However, with the user of the listFiles method, attribute
                // information will not be refreshed automatically from the 
                // server. This means attribute information can become 
                // inconsistent with information about the server.

                IFSFile[] directoryFiles = directory.listFiles(new MyDirectoryFilter(),"*");

                // Tell the user if the directory doesn't exist or is empty

                if (directoryFiles == null)
                {
                    System.out.println("The directory does not exist");
                    return;
                }

                else if (directoryFiles.length == 0)
                {
                    System.out.println("The directory is empty");
                    return;
                }

                for (int i=0; i< directoryFiles.length; i++)
                    {
                        // Print out information on list.
                        // Print the name of the current file

                        System.out.print(directoryFiles[i].getName());


                        // Pad the output so the columns line up

                        for (int j = directoryFiles[i].getName().length(); j <18; j++)
                            System.out.print(" ");


                        // Print the date the file was last changed.

                        long changeDate = directoryFiles[i].lastModified();
                        Date d = new Date(changeDate);
                        System.out.print(d);
                        System.out.print("  ");


                        // Print if the entry is a file or directory

                        System.out.print("   ");

                        if (directoryFiles[i].isDirectory())
                            System.out.println("");
                        else
                            System.out.println(directoryFiles[i].length());

                    }
            }

            catch (Exception e)
            {
                // If any of the above operations failed say the list failed
                // and output the exception.

                System.out.println("List failed");
                System.out.println(e);
            }
        }

        // Display help text when parameters are incorrect.

        else
        {
            System.out.println("");
            System.out.println("");
            System.out.println("");
            System.out.println("Parameters are not correct.  Command syntax is:");
            System.out.println("");
            System.out.println("   IFSListFiles as400 directory");
            System.out.println("");
            System.out.println("Where");
            System.out.println("");
            System.out.println("   as400 = system that contains the files");
            System.out.println("   directory = directory to be listed");
            System.out.println("");
            System.out.println("For example:");
            System.out.println("");
            System.out.println("   IFSListFiles mySystem /dir1/dir2");
            System.out.println("");
            System.out.println("");
        }

        System.exit(0);
    }
}


////////////////////////////////////////////////////////////////////////////
//
// The directory filter class prints information from the file object.
//
// Another way to use the filter is to simply return true or false
// based on information in the file object.  This lets the mainline
// function decide what to do with the list of files that meet the
// search criteria.
//
////////////////////////////////////////////////////////////////////////////



class MyDirectoryFilter implements IFSFileFilter
{
    public boolean accept(IFSFile file)
    {
        try
        {
            // Keep this entry.  Returning true tells the IFSList object
            // to return this file in the list of entries returned to the
            // .list() method.

            return true;
        }

        catch (Exception e)
        {
            return false;
        }
    }
}