package org.infinispan.api.tree;
import org.infinispan.commons.equivalence.AnyEquivalence;
import org.infinispan.tree.Fqn;
import org.infinispan.tree.impl.NodeKey;
import org.infinispan.util.concurrent.locks.containers.LockContainer;
import org.infinispan.util.concurrent.locks.containers.ReentrantStripedLockContainer;
import org.testng.annotations.Test;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.locks.Lock;
/**
* Tests the degree to which hash codes get spread
*/
@Test(groups = "unit", testName = "api.tree.TreeStructureHashCodeTest")
public class TreeStructureHashCodeTest {
public void testHashCodesAppendedCount() {
List<Fqn> fqns = new ArrayList<Fqn>();
fqns.add(Fqn.ROOT);
for (int i = 0; i < 256; i++) fqns.add(Fqn.fromString("/fqn" + i));
doTest(fqns);
}
public void testHashCodesAlpha() {
List<Fqn> fqns = new ArrayList<Fqn>();
fqns.add(Fqn.ROOT);
for (int i = 0; i < 256; i++) fqns.add(Fqn.fromString("/" + Integer.toString(i, 36)));
doTest(fqns);
}
private void doTest(List<Fqn> fqns) {
LockContainer container = new ReentrantStripedLockContainer(512, AnyEquivalence.getInstance());
Map<Lock, Integer> distribution = new HashMap<Lock, Integer>();
for (Fqn f : fqns) {
NodeKey dataKey = new NodeKey(f, NodeKey.Type.DATA);
NodeKey structureKey = new NodeKey(f, NodeKey.Type.STRUCTURE);
addToDistribution(container.getLock(dataKey), distribution);
addToDistribution(container.getLock(structureKey), distribution);
}
assert distribution.size() <= container.size() : "Cannot have more locks than the container size!";
// assume at least a 2/3rd even distribution
// but also consider that data snd structure keys would typically provide the same hash code
// so we need to double this
assert distribution.size() * 1.5 * 2 >= container.size() : "Poorly distributed! Distribution size is just " + distribution.size() + " and there are " + container.size() + " shared locks";
}
private void addToDistribution(Lock lock, Map<Lock, Integer> map) {
int count = 1;
if (map.containsKey(lock)) count = map.get(lock) + 1;
map.put(lock, count);
}
}