### Question:
ItemsetTree { public ItemsetTree(final Multiset<Integer> singletons) { items = singletons; } ItemsetTree(final Multiset<Integer> singletons); Itemset randomWalk(); void traverse(final ItemsetTreeNode node, final Itemset itemset); void buildTree(final File inputFile); void buildTree(final String hdfsPath, final FileSystem hdfs); int[] append(final int[] a1, final int[] a2); void printStatistics(final Logger logger); void printTree(); @Override String toString(); double getChiSquared(final Itemset set1, final Itemset set2, final Itemset set1And2); int getCachedItemsetSupport(); double getChiSquaredOfItemset(final Itemset set, final Multiset<Integer> singletons); int getSupportOfItemset(final Itemset set); double getRelativeSupportOfItemset(final Itemset set); int getNoTransactions();  }### Answer:
@Test public void testItemsetTree() throws IOException { final File input = getTestFile("contextItemsetTree.txt"); final Multiset<Integer> singletons = ItemsetMining .scanDatabaseToDetermineFrequencyOfSingleItems(input); final ItemsetTree itemsetTree = new ItemsetTree(singletons); itemsetTree.buildTree(input); System.out.println("THIS IS THE TREE:"); itemsetTree.printTree(); System.out .println("EXAMPLE QUERIES: FIND THE SUPPORT OF SOME ITEMSETS:"); final int supp123 = itemsetTree .getSupportOfItemset(new Itemset(1, 2, 3)); System.out.println("the support of 1 2 3 is : " + supp123); assertEquals(1, supp123); final int supp2 = itemsetTree.getSupportOfItemset(new Itemset(2)); System.out.println("the support of 2 is : " + supp2); assertEquals(5, supp2); final int supp24 = itemsetTree.getSupportOfItemset(new Itemset(2, 4)); System.out.println("the support of 2 4 is : " + supp24); assertEquals(3, supp24); final int supp12 = itemsetTree.getSupportOfItemset(new Itemset(1, 2)); System.out.println("the support of 1 2 is : " + supp12); assertEquals(2, supp12); }