Help is available for each task.

Task 1

Either start with the skeleton code or create a SparseBitSet class. The skeleton provides a no-argument constructor only. Since the bitmap will be sparse, you shouldn't provide a constructor that will preallocate any space, as BitMap does. Besides a constructor, the skeleton defines the clear(), clone(), equals(), get(), hashCode(), set(), size(), and toSting() method.

In the skeleton, the getBitSet() method returns the internal Set used to store the bits. You should use this method as you complete the other methods in the subclass. The actual HashSet used to store the bit values is created for you in the constructor.

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Shift click to save the file to your working directory.

Task 2

Working alphabetically, the first method to complete is the and(BitSet set) method. This method performs a logical AND of the two bit sets. Only those bits in both sets are in the resulting set. Complete the and() method to combine the internal Set with that of the argument.

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The retainAll() method of Set() retains only the elements in this set that are contained in the other set.

Task 3

The next method to complete is the andNot(BitSet set) method. Instead of keeping bits present in both, the andNot() operation will remove bits from the current set that are also in the set passed as an argument. This is sometimes called a logical NAND operation.

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The removeAll() method of Set() removes the elements in this set that are contained in the other set.

Task 4

Since the clear(), clone(), equals(), get(), and hashCode() methods are defined in the skeleton code, the next method to complete is the length() method. The length() method returns the logical size of the BitSet, which is defined to be the position of the highest set bit, plus one. Thus, if bit 127 was set, the length would be 128 as the bit counting starts at zero.

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The max() method of Collections() reports the highest value in a collection. Make sure you check for an empty set, as an empty set reports zero, not one.

Task 5

The last easy method to complete is the or(BitSet set) method. This method performs a logical OR operation of the two bit sets. Every bit set of either set is in the resulting set.

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The addAll() method of Set() combines the elements of two sets.

Task 6

With the set(), size(), and toString() methods already defined for you, you're left to complete the xor(BitSet set) method. This method performs a logical exclusive or (XOR) operation. Only those bits on in one of the sets will be on in the resulting set.

Unlike the other operations, the solution is not just a single method call of Set.

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You need to find out what elements are in each set that are not in the other set without altering the original sets. Once you have these two sets, combine them to create the resulting set.

Task 7

Compile your program and run the Tester program to see what happens. The Tester program creates a couple of sets and performs all the operations.

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Check your output to make sure the various set operations are correct.

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