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compiling java

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  compiling java Popping mad <rainbow@colition.gov> - 2016-04-12 00:07 +0000
    Re: compiling java Arne Vajhøj <arne@vajhoej.dk> - 2016-04-12 00:00 -0400
      Re: compiling java Andreas Leitgeb <avl@logic.at> - 2016-04-12 10:31 +0000
    Re: compiling java Roedy Green <inquiry@mindprod.com> - 2016-07-17 16:26 -0700

#34107 — compiling java

how can I compile this



[ruben@manjaro Downloads]$ javac IPFragApplet.java 
IPFragApplet.java:16: error: package edu.hm.cs.applet.util does not exist
import edu.hm.cs.applet.util.AppletDescription;


package edu.hm.cs.applet;

///////////////////////////////////////////////////////////////////////////////
// Author: Ryan Gilbert (rmgilbe@asu.edu rgilbert@celeritysoft.com)
// 
// Desc  : Simple JApplet that helps visualize datagram fragmentation
//
// Notes : This applet is replaces an applet coded by Albert Huang in 1997
//       : as part of course work at the University of Pennsylvania. 
///////////////////////////////////////////////////////////////////////////////

// Imported Libraries
import javax.swing.tree.*;
import javax.swing.*;

import edu.hm.cs.applet.util.AppletDescription;

import java.awt.*;
import java.awt.event.*;

// Class  : IPFragApplet
// Purpose: Simple Java JApplet that illustrates datagram fragmenation
public class IPFragApplet
        extends JApplet
        implements ActionListener /* Used by Calculate Button click event 
*/
{
    // Constants
    final String DG_BYTE_INFO   = " byte information field";
    final String DG_OFFSET      = "Offset: ";
    final String DG_ID          = "ID: ";
    final String DG_FLAG        = "Flag: ";
    final int INT_MAX            = 65535; // 2^16 - 1         
    
    
    // Display Labels
    JLabel lblDGSize;
    JLabel lblMTU;
    JLabel lblID;
    JLabel lblMsg;
    
    // Corresponding Text Fields
    JTextField txtDGSize;
    JTextField txtMTU;
    JTextField txtID;
    
    // Tree View with results
    JTree tvwFrags;
    DefaultMutableTreeNode nodRoot;
    
    // Button used to initiate calculations
    JButton btnCalc;
    
    // Panels to organize GUI
    JPanel pnlUpperBorder;
    JPanel pnlMain;
    JPanel pnlBottom;
    JPanel pnlTree;
            
    // Method : init
    // Purpose: Instantiate all of the controls and perform the setup
    @Override
    public void init()
    {
        // Create the labels and their corresponding text fields
        lblDGSize = new JLabel("Datagram Size: ");
        lblMTU = new JLabel("MTU: ");
        lblID = new JLabel("Datagram ID: ");
        
        txtDGSize = new JTextField();
        txtMTU = new JTextField();
        txtID = new JTextField();
        
        // Create tree view to display the resulting fragments
        // Root tree node
        nodRoot = new DefaultMutableTreeNode("Fragments");
        tvwFrags = new JTree(nodRoot);
        tvwFrags.setRootVisible(true);
        tvwFrags.setShowsRootHandles(true);
                
        
        // Create the button used to initiate the calculation and setup
        // the action listener
        btnCalc = new JButton("Calculate");
        btnCalc.addActionListener(this);
        
        // Create Error label for displaying errors. It is also used
        // to display the number of fragments.
        lblMsg = new JLabel("");
        lblMsg.setForeground(Color.red);
        
        // Create the panel for the bottom to hold the calculate button
        pnlBottom = new JPanel();
        pnlBottom.setLayout( new BoxLayout(pnlBottom, BoxLayout.X_AXIS));
        
        // This causes the button to spring to the right side. I hate
        // Java layout managers, but I am dealing with it.
        pnlBottom.add(Box.createRigidArea(new Dimension(10,10)));
        pnlBottom.add(lblMsg);
        pnlBottom.add(Box.createHorizontalGlue());
        pnlBottom.add(btnCalc);
        pnlBottom.add(Box.createRigidArea(new Dimension(10,10)));
        
        /* add applet description
        AppletDescription theDesc = new AppletDescription(this, 
				"Ryan Gilber, Arizona State University",
				"IP Fragmentation Visualization. Datagram 
size includes an IP header of 20 bytes. MTU and Datagram size must be 
greater than 30, and all values must be less than 2^16 - 1 (65535).");
		pnlBottom.add(theDesc);
		*/
		
		pnlBottom.add(Box.createRigidArea(new Dimension(10,10)));
        
        // Create the upper panel holding all the labels and text fields
        pnlUpperBorder = new JPanel();
        pnlUpperBorder.setLayout(
                new BoxLayout(pnlUpperBorder, BoxLayout.X_AXIS));
        
        // Add each control and then a ten pixel spacer
        pnlUpperBorder.add(Box.createRigidArea(new Dimension(10,10)));
        pnlUpperBorder.add(lblDGSize);
        pnlUpperBorder.add(Box.createRigidArea(new Dimension(10,10)));
        pnlUpperBorder.add(txtDGSize);
        pnlUpperBorder.add(Box.createRigidArea(new Dimension(10,10)));
        pnlUpperBorder.add(lblMTU);
        pnlUpperBorder.add(Box.createRigidArea(new Dimension(10,10)));
        pnlUpperBorder.add(txtMTU);
        pnlUpperBorder.add(Box.createRigidArea(new Dimension(10,10)));
        pnlUpperBorder.add(lblID);
        pnlUpperBorder.add(Box.createRigidArea(new Dimension(10,10)));
        pnlUpperBorder.add(txtID);
        pnlUpperBorder.add(Box.createRigidArea(new Dimension(10,10)));
        
        // Create tree panel
        pnlTree = new JPanel();
        pnlTree.setLayout(new BoxLayout(pnlTree, BoxLayout.X_AXIS));
        pnlTree.add(Box.createRigidArea(new Dimension(10,10)));
        
        // Use a scroll pane for the tree view in case the text
        // expands past the size of the applet        
        pnlTree.add(new JScrollPane(tvwFrags));
        pnlTree.add(Box.createRigidArea(new Dimension(10,10)));
        
        
        // Create main panel to hold everything
        pnlMain = new JPanel();
        pnlMain.setLayout(
                new BorderLayout());
        
        // Add child panels to our main root panel
        pnlMain.add(pnlUpperBorder, BorderLayout.NORTH);
        pnlMain.add(pnlTree, BorderLayout.CENTER);
        pnlMain.add(pnlBottom, BorderLayout.SOUTH);
        
        this.setContentPane(pnlMain);
    }

    // Method : actionPerformed
    // Purpose: Called when calculate is clicked. This method will 
validate
    //        : the text fields and then generate the appropriate tree 
nodes
    public void actionPerformed(ActionEvent e)
    {
        // Locals used for calculations
        int iMTU = 0;
        int iSize = 0;
        int iID = 0;
        
        // Clear msg/error text
        lblMsg.setText("");
        
        try
        {
            // Never trust user input. Try to parse the text.
            iMTU = Integer.parseInt(txtMTU.getText());
            iSize = Integer.parseInt(txtDGSize.getText());
            iID = Integer.parseInt(txtID.getText());
            
            // Basically these parameters could be checked better, but
            // I currently require the datagram size to be over 30 bytes
            // and the MTU has to be over 30 bytes while they are all a 
valid
            // 16-bit integer.
            // If the data is valid...
            if(iMTU > 30 && iMTU <= INT_MAX && iSize > 30 && iSize <= 
INT_MAX
                    && iID > 0 && iID <= INT_MAX)
            {   
                // Used in calculations and text rendering
                int iInfoSizeFlag1 = (iMTU - 20) - ((iMTU - 20) % 8);  //
intermediate fragments MUST be multiple of 8 bytes
                int iInfoSizeFlag0 = (iMTU - 20); // last fragment can 
use all bytes (even if not multiple of 8)
                String sInfoSizeFlag1 = new Integer
(iInfoSizeFlag1).toString();
                String sInfoSizeFlag0 = new Integer
(iInfoSizeFlag0).toString();
                int iRemainder = (iSize - 20) % iInfoSizeFlag1;
             
                // Get number of datagrams
                int iDGCount = (int) Math.ceil(
                        (double) (iSize - 20) / iInfoSizeFlag1);
                
                if (iRemainder <= (iInfoSizeFlag0-iInfoSizeFlag1)){
                	// can put remainder in last packet (must not be 
multiple of 8 bytes)
                	iDGCount--;
                	iRemainder = 0;
                }
                
                // Remove all the current nodes
                nodRoot.removeAllChildren();

                // For each datagram...
                for(int i = 0; i < iDGCount; i++)
                {
                    // Root for current datagram
                    DefaultMutableTreeNode nodNew =
                            new DefaultMutableTreeNode("Datagram " + (i + 
1));
                    
                    // If we are not on the last datagram...
                    if (i + 1 < iDGCount)
                    {
                        DefaultMutableTreeNode nodInfo =
                                new DefaultMutableTreeNode(
                                		sInfoSizeFlag1 + 
DG_BYTE_INFO);
                        nodNew.add(nodInfo);
                    }
                    else
                    {
                        // Calculate the remaining bytes to be sent
                        String sTemp = "";
                        
                        sTemp = (iRemainder == 0) ?
                        		Integer.toString(((iSize - 20)-
(i*iInfoSizeFlag1))) :
                            new Integer( iRemainder ).toString();
                        
                        DefaultMutableTreeNode nodInfo =
                                new DefaultMutableTreeNode(
                                sTemp + DG_BYTE_INFO);
                        
                        nodNew.add(nodInfo);                        
                    }
                    
                    // Create ID
                    DefaultMutableTreeNode nodID =
                        new DefaultMutableTreeNode(
                            DG_ID + iID);
                        
                    nodNew.add(nodID);  
                    
                    // Create Offset
                    DefaultMutableTreeNode nodOffset =
                        new DefaultMutableTreeNode(
                            DG_OFFSET + (i * iInfoSizeFlag1 / 8));
                        
                    nodNew.add(nodOffset);                     
                    
                    // Create Flag
                    DefaultMutableTreeNode nodFlag = null;
                    
                    // Flag is one or zero for the last
                    String sFlag = (i + 1 < iDGCount) ?
                        DG_FLAG + "1" : DG_FLAG + "0";
                    
                    nodFlag = new DefaultMutableTreeNode(sFlag);

                    nodNew.add
(nodFlag);                                        
                    
                    nodRoot.add(nodNew);
                }
                
                // Label will be used to display number of datagrams 
instead
                // of an error message, since we did not get an error
                lblMsg.setForeground(Color.blue);
                lblMsg.setText("Number of Datagrams: " + iDGCount);
                
                // Needed to refresh the tree. Not sure why the control
                // doesn't do this automatically when you change the nodes
                ((DefaultTreeModel)tvwFrags.getModel()).reload();
            
            }
            else
                // Invalid parameters, let the handler deal with it.
                throw new NumberFormatException();
        }
        catch(NumberFormatException errBadInput)
        {
            lblMsg.setForeground(Color.red);
            lblMsg.setText("Verify parameters are valid integers.");
        }
        catch(Exception errGeneric)
        {
            lblMsg.setForeground(Color.red);
            lblMsg.setText("Error: " + errGeneric.getMessage
());            
        }
    }
}

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#34108

On 4/11/2016 8:07 PM, Popping mad wrote:
> how can I compile this
>
> [ruben@manjaro Downloads]$ javac IPFragApplet.java
> IPFragApplet.java:16: error: package edu.hm.cs.applet.util does not exist
> import edu.hm.cs.applet.util.AppletDescription;

javac -cp wherever_edu_hm_cs_applet_are.jar IPFragApplet.java

Arne

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#34111

Arne Vajhøj <arne@vajhoej.dk> wrote:
> On 4/11/2016 8:07 PM, Popping mad wrote:
>> how can I compile this
>> [ruben@manjaro Downloads]$ javac IPFragApplet.java
>> IPFragApplet.java:16: error: package edu.hm.cs.applet.util does not exist
>> import edu.hm.cs.applet.util.AppletDescription;
> javac -cp wherever_edu_hm_cs_applet_are.jar IPFragApplet.java

Not quite.
The package that is not found is a subpackage of the one the current
class resides in. But then again, according to the shell prompt it
seems like he executes the javac from a directory named Downloads and
IPFragApplet.java seems to be directly in that directory, rather than
in a nested subdirectory that corresponds to the source-file's package:
edu/hm/cs/applet .  This alone wouldn't yet be a problem, but there is
also another source file that should be in edu/hm/cs/applet/util/ but
might be also in current directory (or just hasn't been unzipped, yet).
That way, however, javac won't find it.

Probably you ("Popping mad") unzipped some downloaded .jar (or .zip)
with option "-j" (for unzip) that discarded the directory structure
when extracting.

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#34947

On Tue, 12 Apr 2016 00:07:21 +0000 (UTC), Popping mad
<rainbow@colition.gov> wrote:

>IPFragApplet.java:16: error: package edu.hm.cs.applet.util does not exist

Find this and check you have the spelling precisely correct.
Make sure it is  on the classpath

see http://mindprod.com/jgloss/classpath.html

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