Setter for a key value pair List object

Question

I am stumped with this one and hoping to see if this could be a good way to solve my issue.

I'll first explain how the program works.

I have a class that is simply a key value pair:

   public class KeyValuePair {
   private final String name;
   private final String value;

   public KeyValuePair(String n, String v) {
    name = n;
    value = v;
}

I have another class called List that uses the key value pair.

   public class myList {

private List<KeyValuePair> myList = new ArrayList<KeyValuePair>();


public myList(List<KeyValuePair> nvp) {
    List = nvp;
}

public List<KeyValuePair> getList() {
    return myList;
}
}

So in my program i then create an List object and populate it with the key value pairs and review a new List(kvp).

 public myList pullData(){
 Final myList<KeyValuePair> nvp = new ArrayList<KeyValuePair>();
 List<String[]> results = getResults()

    for(String[] str : results)
    {
     KeyValuePair kvp = new KeyValuePair(str[0], str[1]);
     nvp.add(kvp)
    }
 }
 return new myList(nvp)
}

now I have run into the situation where I need to update the value of each pair. The key stays the same.

Originally I had created a newList object and populated with the updated Value for the key pair, but then though there should be a better method, perhaps creating an update or a setter method within the List object to do this.

Which would be better creating a new object, or updating? I would think updating the value in the key value pair, however, I am not sure how to do this.

Any help or suggestions would be greatly appreciated.

Answer 1

Then you can set the keys and values if you want:

public class KeyValuePair {
  private String name;
  private String value;

  public KeyValuePair(String n, String v) {
      name = n;
     value = v;
  }
  public String getName(){
     return name;
  }
  public String getValue(){
     return value;
  }

  public void setName(String n){
     name = n;
  }

  public void setValue(String v){
      value = v;
  }

}

However a list of these is never going to be as useful as a map that is already there in Java.

Answer 2

Lose final modifier and create nice getters and setters for your fields

public class KeyValuePair {
    private String name;
    private String value;

    public KeyValuePair(String n, String v) {
        name = n;
        value = v;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }

}

and then you can e.g. add plus sign to your values:

public void update(List<KeyValuePair> pairs) {
        for (KeyValuePair kvp: pairs) {
            kvp.setValue(kvp.getValue() + "+");
        }
    }

Answer 3

Simply by adding a setter to my key value pair class resolved this issue. Not too sure why i didn't see that before, for some reason I thought I needed to do it in myList class.

public void setValue (String newValue){
    value = newValue;
}