I am using the code from the answer How do I create a new AnyType[] array? . My question is how to initialize this array. When I try to run this code, I get a null pointer exception on Clear(), which I think is due to using theItems.getClass since theItems haven't been declared already.
public class Whatever<AnyType extends Comparable<? super AnyType>> extends AbstractCollection<AnyType> implements List<AnyType> {
private static final int DEFAULT_CAPACITY = 10;
private static final int NOT_FOUND = -1;
private AnyType[] theItems;
private int theSize;
private int modCount = 0;
public Whatever() {
clear();
}
/**
* Change the size of this collection to zero.
*/
public void clear() {
theSize = 0;
theItems = (AnyType[]) java.lang.reflect.Array.newInstance(theItems.getClass().getComponentType(), DEFAULT_CAPACITY);
modCount++;
}
}
So I found two ways I could accomplish this. The first, using Jack's comment from above, looks like:
public static <T> T[] alloc(int length, T ... base) {
return Arrays.copyOf( base, length );
}
It can then be called like:
theItems = ClassName.alloc(DEFAULT_CAPACITY);
The way I ended up using could be used because I implemented comparable:
theItems = (AnyType []) new Comparable[ DEFAULT_CAPACITY ];
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