Is this even solvable?

Question about the task

Table

Java Core, Level 8, Lesson 8

Resolved

Anyone have any idea how the 'list' is supposed to come into play?

Change the TableInterfaceWrapper class so that it wraps TableInterface.
The setModel method should display the number of elements in the new list before updating the model.
The getHeaderText method should return the text in upper case. Use the toUpperCase() method.

Requirements:

The TableInterfaceWrapper class must implement the TableInterface interface.
The TableInterfaceWrapper class must initialize a TableInterface field in the constructor.
The setModel() method should display the number of elements in the new list before updating the model.
The getHeaderText() method must return the text in uppercase.
The setHeaderText() method must set the header text without making changes.

package com.codegym.task.task18.task1815; import java.util.ArrayList; import java.util.List; /* Table */ public class Solution { public class TableInterfaceWrapper implements TableInterface{ private TableInterface tableInterface; List list = new ArrayList(); String headerText = null; public TableInterfaceWrapper(TableInterface tableInterface) { this.tableInterface = tableInterface; } @Override public void setModel(List rows) { list = new ArrayList(); System.out.println(list.size()); list.addAll(rows); } @Override public String getHeaderText() { return headerText.toUpperCase(); } @Override public void setHeaderText(String headerText) { this.headerText = headerText; } } public interface TableInterface { //static List list = new ArrayList(); void setModel(List rows); String getHeaderText(); void setHeaderText(String newHeaderText); } public static void main(String[] args) { } }

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Guadalupe Gagnon

Level 37 , Tampa, United States

31 January 2019, 20:57

I messaged you. Basically the constructor takes a tableInterface. Interfaces can not be made into objects, however classes that implement them can, so what would be passed into this would be a class that implements tableInterface. The methods should do what the task requirements say, but delegate everything else to the object saved as the initialized tableInterface. So for setHeaderText, the code only has to delegate it to the object like so:

public void setHeaderText(String headerText)
{
   tableInterface.setheaderText(headerText);
}

and then when you are supposed to do something according to the task, the code would be:

public String getHeaderText()
{
   return tableInterface.getHeaderText().toUpperCase();
}

No need to add properties other than the TableInterface object.