Can we set capacity to a arraylist

Question

I want a arraylist[strings] with max capacity of 4 values

Answer 1

https://stackoverflow.com/questions/3564837/capacity-of-arraylist

Answer 2

ArrayList is designed to resize dynamically, so you can set an initial capacity but this can resize if you try to add more.

You could wrap a class around it that can perform this check:

public class FixedCapacityList<T> {
private int maxSize;
private ArrayList<T> dataList;

// constructor
public FixedCapacityList(int size) {
maxSize = size;
dataList = new ArrayList<>(size);
}

public boolean add(T data) {
if (dataList.size() >= maxSize) {
return false;
} else {
return dataList.add(data);
}
}

So this class wraps an ArrayList and stops you adding more than the desired amount of data. You could throw an exception if you want instead.

Answer 3

https://docs.oracle.com/javase/8/docs/api/java/util/ArrayList.html

in fact, since the class is not final you could just extend it and override the add method to not allow more than the number of elements you want

Answer 4

thanks