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how to instantiate an obect  - ?

Posted on 2008-10-20
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Last Modified: 2013-11-23
I have a class LinkedStack (see first code snippet) but when I try to call the method to push an object onto it netbeans keeps telling me it cannot find the method?


Tks,
Owen.



public class LinkedStack 

{

    private node top;

    private int size;

    public LinkedStack()

    {

        top = null;

        size = 0;

    }

    public int size()

    {

        return size;

    }

    public boolean isEmpty()

    {

    if(top == null)

        return true;

    else return false;

    }

    public Object top() throws StackException

    {if (isEmpty())

        throw new StackException("Stack is empty");

        return top.getElement();

    }

    public void push(Object obj)

    {

    node n = new node();

    n.setElement(obj);

    n.setNext(top);

    top = n;

    size++;

    }

#####################

public class linkQueue extends javax.swing.JFrame {
 

    public linkQueue() {

        initComponents();

    }

    

    /** This method is called from within the constructor to

     * initialize the form.

     * WARNING: Do NOT modify this code. The content of this method is

     * always regenerated by the Form Editor.

     */

    // <editor-fold defaultstate="collapsed" desc="Generated Code">

    private void initComponents() {
 

        jLabel1 = new javax.swing.JLabel();

        jLabel2 = new javax.swing.JLabel();

        jLabel3 = new javax.swing.JLabel();

        jLabel4 = new javax.swing.JLabel();

        empNumTextField = new javax.swing.JTextField();

        empFirstNameTextField = new javax.swing.JTextField();

        empLastNameTextField = new javax.swing.JTextField();

        empAgeTextField = new javax.swing.JTextField();

        jScrollPane1 = new javax.swing.JScrollPane();

        jTextArea1 = new javax.swing.JTextArea();

        insertButton = new javax.swing.JButton();

        deleteButton = new javax.swing.JButton();

        searchButton = new javax.swing.JButton();

        qSizeButton = new javax.swing.JButton();

        frontButton = new javax.swing.JButton();
 

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
 

        jLabel1.setFont(new java.awt.Font("Tahoma", 1, 12));

        jLabel1.setText("Emp Number:");
 

        jLabel2.setFont(new java.awt.Font("Tahoma", 1, 12));

        jLabel2.setText("First Name:");
 

        jLabel3.setFont(new java.awt.Font("Tahoma", 1, 12));

        jLabel3.setText("Last Name:");
 

        jLabel4.setFont(new java.awt.Font("Tahoma", 1, 12));

        jLabel4.setText("Age:");
 

        empNumTextField.setFont(new java.awt.Font("Tahoma", 1, 12)); // NOI18N
 

        empFirstNameTextField.setFont(new java.awt.Font("Tahoma", 1, 12));
 

        empLastNameTextField.setFont(new java.awt.Font("Tahoma", 1, 12));
 

        empAgeTextField.setFont(new java.awt.Font("Tahoma", 1, 12));
 

        jTextArea1.setColumns(20);

        jTextArea1.setRows(5);

        jScrollPane1.setViewportView(jTextArea1);
 

        insertButton.setLabel("Insert");

        insertButton.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(java.awt.event.ActionEvent evt) {

                insertButtonActionPerformed(evt);

            }

        });
 

        deleteButton.setText("Delete");
 

        searchButton.setText("Search");
 

        qSizeButton.setText("Q Size");
 

        frontButton.setText("Front");
 

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());

        getContentPane().setLayout(layout);

        layout.setHorizontalGroup(

            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

            .addGroup(layout.createSequentialGroup()

                .addContainerGap()

                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

                    .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)

                        .addComponent(jScrollPane1, javax.swing.GroupLayout.Alignment.LEADING)

                        .addGroup(javax.swing.GroupLayout.Alignment.LEADING, layout.createSequentialGroup()

                            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

                                .addComponent(jLabel1)

                                .addComponent(jLabel2)

                                .addComponent(jLabel3)

                                .addComponent(jLabel4))

                            .addGap(91, 91, 91)

                            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)

                                .addComponent(empAgeTextField)

                                .addComponent(empLastNameTextField)

                                .addComponent(empFirstNameTextField)

                                .addComponent(empNumTextField, javax.swing.GroupLayout.DEFAULT_SIZE, 242, Short.MAX_VALUE))))

                    .addGroup(layout.createSequentialGroup()

                        .addComponent(insertButton, javax.swing.GroupLayout.PREFERRED_SIZE, 61, javax.swing.GroupLayout.PREFERRED_SIZE)

                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)

                        .addComponent(deleteButton)

                        .addGap(15, 15, 15)

                        .addComponent(searchButton)

                        .addGap(15, 15, 15)

                        .addComponent(qSizeButton, javax.swing.GroupLayout.PREFERRED_SIZE, 63, javax.swing.GroupLayout.PREFERRED_SIZE)

                        .addGap(18, 18, 18)

                        .addComponent(frontButton, javax.swing.GroupLayout.PREFERRED_SIZE, 61, javax.swing.GroupLayout.PREFERRED_SIZE)))

                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))

        );

        layout.setVerticalGroup(

            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)

            .addGroup(layout.createSequentialGroup()

                .addContainerGap()

                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)

                    .addComponent(jLabel1)

                    .addComponent(empNumTextField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))

                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)

                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)

                    .addComponent(jLabel2)

                    .addComponent(empFirstNameTextField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))

                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)

                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)

                    .addComponent(jLabel3)

                    .addComponent(empLastNameTextField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))

                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)

                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)

                    .addComponent(jLabel4)

                    .addComponent(empAgeTextField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))

                .addGap(18, 18, 18)

                .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 277, javax.swing.GroupLayout.PREFERRED_SIZE)

                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)

                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)

                    .addComponent(insertButton)

                    .addComponent(deleteButton)

                    .addComponent(searchButton)

                    .addComponent(qSizeButton)

                    .addComponent(frontButton))

                .addContainerGap(19, Short.MAX_VALUE))

        );
 

        pack();

    }// </editor-fold>
 

private void insertButtonActionPerformed(java.awt.event.ActionEvent evt) {

// TODO add your handling code here:

     String inText = empFirstNameTextField.getText() + empLastNameTextField.getText() + 

            empNumTextField.getText() + empAgeTextField.getText();

     

    push(inText); // error here, please help

}

    

  

    public static void main(String args[]) {

        java.awt.EventQueue.invokeLater(new Runnable() {

            public void run() {

                new linkQueue().setVisible(true);

                LinkedStack myStack = new LinkedStack();

            }

            

        });

    }

    

    // Variables declaration - do not modify

    private javax.swing.JButton deleteButton;

    private javax.swing.JTextField empAgeTextField;

    private javax.swing.JTextField empFirstNameTextField;

    private javax.swing.JTextField empLastNameTextField;

    private javax.swing.JTextField empNumTextField;

    private javax.swing.JButton frontButton;

    private javax.swing.JButton insertButton;

    private javax.swing.JLabel jLabel1;

    private javax.swing.JLabel jLabel2;

    private javax.swing.JLabel jLabel3;

    private javax.swing.JLabel jLabel4;

    private javax.swing.JScrollPane jScrollPane1;

    private javax.swing.JTextArea jTextArea1;

    private javax.swing.JButton qSizeButton;

    private javax.swing.JButton searchButton;

    // End of variables declaration

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Comment
Question by:OwenMoriarty
  • 2
4 Comments
 
LVL 8

Assisted Solution

by:MatthiasVance
MatthiasVance earned 100 total points
ID: 22762427
You have to do something like the following in your code.

Kind regards,

Matthias Vance
// Instantiate a LinkedStack object

LinkedStack ls = new LinkedStack();

ls.push(inText);

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LVL 8

Accepted Solution

by:
mkosbie earned 400 total points
ID: 22762473
You need an actual LinkedStack you're working with, then you call the method of that instance.
public class linkQueue extends javax.swing.JFrame {

    //add a LinkedStack here

    private LinkedStack stack;
 

    //add to your contructor

    public linkQueue() {

        initComponents();

        stack = new LinkedStack();

    }
 

    //

    // all the other code you already have

    //
 

// edited insertButtonActionPerformed

private void insertButtonActionPerformed(java.awt.event.ActionEvent evt) {

// TODO add your handling code here:

     String inText = empFirstNameTextField.getText() + empLastNameTextField.getText() + 

            empNumTextField.getText() + empAgeTextField.getText();

     

    stack.push(inText); // error here, please help

}
 

}

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0
 

Author Comment

by:OwenMoriarty
ID: 22762684
Did that but now I get cannot find symbol in three places. 1. where I name myStack a linked stack, 2. where i give it new and 3. where I try to invoke the push method.. Any suggestion. I have attached a screenshot. Please also note the way the source files are laid out, is there a problem with that?

Thank you,
Owen.
stacks-EE.JPG
0
 

Author Closing Comment

by:OwenMoriarty
ID: 31508041
Figured out my second problem, I allowed netbeans to refactor when I moved all source files to the same directory. Tks for help.
0

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