ItemsRange.java

package hong.specialEffects.wheel;

/**
 * Range for visible items.
 */
public class ItemsRange {
        // First item number
        private int first;
        
        // Items count
        private int count;

        /**
         * Default constructor. Creates an empty range
         */
    public ItemsRange() {
        this(0, 0);
    }
    
        /**
         * Constructor
         * @param first the number of first item
         * @param count the count of items
         */
        public ItemsRange(int first, int count) {
                this.first = first;
                this.count = count;
        }
        
        /**
         * Gets number of  first item
         * @return the number of the first item
         */
        public int getFirst() {
                return first;
        }
        
        /**
         * Gets number of last item
         * @return the number of last item
         */
        public int getLast() {
                return getFirst() + getCount() - 1;
        }
        
        /**
         * Get items count
         * @return the count of items
         */
        public int getCount() {
                return count;
        }
        
        /**
         * Tests whether item is contained by range
         * @param index the item number
         * @return true if item is contained
         */
        public boolean contains(int index) {
                return index >= getFirst() && index <= getLast();
        }
}