add Bound and Range

src/sort/Bound.java

+package sort;
+
+public enum Bound {
+	LOWER, UPPER, LOWHIGH, ANY;
+}

src/sort/Range.java

+package sort;
+
+public class Range<Key extends Comparable<Key>> {
+	private final Bound boundType;
+	private final Key lower;
+	private final Key upper;
+	
+	public Range(Bound bt) throws Exception {
+		if (bt == Bound.ANY) {
+			boundType = bt;
+			lower = null;
+			upper = null;
+		}
+		else
+			throw new Exception("Must provide ANY bound.");
+	}
+	
+	public Range(Bound bt, Key upperOrLower) throws Exception {
+		if (bt == Bound.UPPER) {
+			upper = upperOrLower;
+			lower = null;
+		} else if (bt == Bound.LOWER) {
+			upper = upperOrLower;
+			lower = null;
+		}
+		else 
+			throw new Exception("Must provide UPPER OR LOWER bound.");
+		boundType = bt;
+	}
+	
+	public Range(Bound bt, Key lower, Key upper) throws Exception {
+		if (bt == Bound.LOWHIGH) {
+			this.lower = lower;
+			this.upper = upper;
+		} else
+			throw new Exception("Must provide LOWHIGH bound.");
+		this.boundType = bt;
+	}
+	
+	public boolean inBounds(Key key, GeneralCompare<Key> gc) {
+		if (boundType == Bound.ANY) return true;
+		else if (boundType == Bound.LOWER) 	return gc.compare(lower, key) <= 0;
+		else if (boundType == Bound.UPPER) 	return gc.compare(upper, key) >= 0;
+		else									return gc.compare(lower, key) <= 0 && gc.compare(upper, key) >= 0;
+	}
+}