package rd222dv_assign1.intCollection;

import java.util.Iterator;

/*
 * An abstract class that provides basic support for 
 * array based linear data structures.
 */

public abstract class AbstractIntCollection {
	protected int size = 0;
	protected int[] values = new int[8];

	/* Public interface */
	public int size() {
		return size;
	}

	public boolean isEmpty() {
		return size == 0;
	}

	public String toString() {
		StringBuffer buf = new StringBuffer();
		buf.append("[");
		for (int i = 0; i < size; i++) {
			buf.append(" " + values[i]);
		}

		buf.append(" ]");
		return buf.toString();
	}

	public Iterator<Integer> iterator() {
		return new IntIterator();
	}

	/* Protected help methods that can be used by extending classes */
	protected void resize() {
		int[] tmp = new int[2 * values.length];
		System.arraycopy(values, 0, tmp, 0, values.length);
		values = tmp;
	}

	protected boolean checkIndex(int index, int upper) {
		if (index < 0 || index >= upper) {
			String msg = "Index = " + index + ", Upper boundary = " + upper;
			System.err.println(msg);
			return false;
		}
		return true;
	}

	/* Private inner class used by iterator() */
	class IntIterator implements Iterator<Integer> {
		private int count = 0;

		public Integer next() {
			return values[count++];
		}

		public boolean hasNext() {
			return count < size;
		}

		public void remove() {
			throw new RuntimeException("remove() is not implemented");
		}
	}
}