public void prepare(ColumnFamilyStore cfs) {
if (tree.partitioner() instanceof RandomPartitioner) {
// You can't beat an even tree distribution for md5
tree.init();
} else {
List<DecoratedKey> keys = new ArrayList<DecoratedKey>();
for (DecoratedKey sample : cfs.keySamples(request.range)) {
assert request.range.contains(sample.token)
: "Token " + sample.token + " is not within range " + request.range;
keys.add(sample);
}
if (keys.isEmpty()) {
// use an even tree distribution
tree.init();
} else {
int numkeys = keys.size();
Random random = new Random();
// sample the column family using random keys from the index
while (true) {
DecoratedKey dk = keys.get(random.nextInt(numkeys));
if (!tree.split(dk.token)) break;
}
}
}
logger.debug("Prepared AEService tree of size " + tree.size() + " for " + request);
ranges = tree.invalids();
}
@Test
public void testDifference() {
Range full = new Range(tok(-1), tok(-1));
int maxsize = 16;
mt.maxsize(maxsize);
MerkleTree mt2 = new MerkleTree(partitioner, RECOMMENDED_DEPTH, maxsize);
mt.init();
mt2.init();
TreeRange leftmost = null;
TreeRange middle = null;
TreeRange rightmost = null;
// compact the leftmost, and split the rightmost
Iterator<TreeRange> ranges = mt.invalids(full);
leftmost = ranges.next();
rightmost = null;
while (ranges.hasNext()) rightmost = ranges.next();
mt.compact(leftmost.right);
leftmost = mt.get(leftmost.right); // leftmost is now a larger range
mt.split(rightmost.right);
// set the hash for the left neighbor of rightmost
middle = mt.get(rightmost.left);
middle.hash("arbitrary!".getBytes());
byte depth = middle.depth;
// add dummy hashes to the rest of both trees
for (TreeRange range : mt.invalids(full)) range.addAll(new HIterator(range.right));
for (TreeRange range : mt2.invalids(full)) range.addAll(new HIterator(range.right));
// trees should disagree for leftmost, (middle.left, rightmost.right]
List<TreeRange> diffs = MerkleTree.difference(mt, mt2);
assertEquals(diffs + " contains wrong number of differences:", 2, diffs.size());
assertTrue(diffs.contains(leftmost));
assertTrue(diffs.contains(new Range(middle.left, rightmost.right)));
}
@Test
public void testSerialization() throws Exception {
Range full = new Range(tok(-1), tok(-1));
ByteArrayOutputStream bout = new ByteArrayOutputStream();
ObjectOutputStream oout = new ObjectOutputStream(bout);
// populate and validate the tree
mt.maxsize(256);
mt.init();
for (TreeRange range : mt.invalids(full)) range.addAll(new HIterator(range.right));
byte[] initialhash = mt.hash(full);
oout.writeObject(mt);
oout.close();
ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
ObjectInputStream oin = new ObjectInputStream(bin);
MerkleTree restored = (MerkleTree) oin.readObject();
// restore partitioner after serialization
restored.partitioner(partitioner);
assertHashEquals(initialhash, restored.hash(full));
}