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GenericArrayListQueue.java
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42 lines (36 loc) · 1.13 KB
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import java.util.ArrayList;
public class GenericArrayListQueue<T> {
ArrayList<T> _queue = new ArrayList<T>();
private boolean hasElements() {
return !_queue.isEmpty();
}
public T peek() {
T result = null;
if(this.hasElements()) { result = _queue.get(0); }
return result;
}
public boolean add(T element) {
return _queue.add(element);
}
public T poll() {
T result = null;
if(this.hasElements()) { result = _queue.remove(0); }
return result;
}
public static void main(String[] args) {
GenericArrayListQueue<Integer> queue = new GenericArrayListQueue<Integer>();
System.out.println("Running...");
assert queue.peek() == null;
assert queue.poll() == null;
assert queue.add(1) == true;
assert queue.peek() == 1;
assert queue.add(2) == true;
assert queue.peek() == 1;
assert queue.poll() == 1;
assert queue.peek() == 2;
assert queue.poll() == 2;
assert queue.peek() == null;
assert queue.poll() == null;
System.out.println("Finished.");
}
}