/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.ignite.lang.utils;
import java.util.Arrays;
import java.util.Collection;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;
import java.util.UUID;
import java.util.concurrent.atomic.AtomicInteger;
import org.apache.ignite.internal.util.GridConsistentHash;
import org.apache.ignite.internal.util.typedef.F;
import org.apache.ignite.testframework.junits.common.GridCommonAbstractTest;
import org.apache.ignite.testframework.junits.common.GridCommonTest;
/**
* Consistent hash test.
*/
@SuppressWarnings({"AssertWithSideEffects"})
@GridCommonTest(group = "Lang")
public class GridConsistentHashSelfTest extends GridCommonAbstractTest {
/** */
private static final int NODES = 20;
/** */
private static final int REPLICAS = 512;
/**
* Initializes hash.
*
* @param hash Hash to initialize.
* @param replicas Replicas.
* @param nodes Array of nodes.
* @return Passed in hash for chaining.
*/
private GridConsistentHash<UUID> initialize(GridConsistentHash<UUID> hash, int replicas, UUID... nodes) {
assert hash != null;
int before = hash.count();
for (UUID node : nodes) {
int cnt = hash.count();
assert hash.addNode(node, replicas);
assertEquals(cnt + 1, hash.count());
}
int after = hash.count();
assert before + nodes.length == after : "Invalid number of nodes [hashed=" + hash.nodes() +
", added=" + Arrays.toString(nodes) + ']';
return hash;
}
/**
* @param hash Hash to clean.
*/
private void clean(GridConsistentHash<UUID> hash) {
if (hash != null) {
int cnt = hash.count();
assert hash.removeNode(hash.random());
assertEquals(cnt - 1, hash.count());
// info("Cleaning nodes", hash.nodes());
hash.removeNodes(hash.nodes());
hash.clear();
assertEquals(0, hash.size());
assertEquals("Invalid hash: " + hash.nodes(), 0, hash.count());
assert hash.isEmpty();
}
}
/**
* Test hash codes collisions.
*
* @throws Exception In case of any exception.
*/
public void testCollisions() throws Exception {
Map<Integer, Set<UUID>> map = new HashMap<>();
// Different nodes, but collide hash codes.
Collection<UUID> nodes = new LinkedHashSet<>();
// Generate several nodes with collide hash codes.
while (nodes.size() < 8) {
UUID uuid = UUID.randomUUID();
int hashCode = uuid.hashCode();
Set<UUID> set = map.get(hashCode);
if (set == null)
map.put(hashCode, set = new LinkedHashSet<>());
set.add(uuid);
if (set.size() > 1)
nodes.addAll(set);
}
map.clear(); // Clean up.
GridConsistentHash<UUID> hash = new GridConsistentHash<>();
hash.addNodes(nodes, REPLICAS);
boolean fail = false;
for (UUID exp : nodes) {
UUID act = hash.node(0, Arrays.asList(exp));
if (exp.equals(act))
info("Validation succeed [exp=" + exp + ", act=" + act + ']');
else{
info("Validation failed [exp=" + exp + ", act=" + act + ']');
fail = true;
}
}
if (fail)
fail("Failed to resolve consistent hash node, when node's hash codes collide: " + nodes);
}
/**
* Test restrictions from internal {@link TreeSet} usage.
*
* @throws Exception In case of any exception.
*/
public void testTreeSetRestrictions() throws Exception {
// Constructs hash without explicit node's comparator.
GridConsistentHash<Object> hash = new GridConsistentHash<>();
try {
// Add several objects with the same hash without neigther natural ordering nor comparator.
hash.addNode(new Object() { public int hashCode() { return 0; } }, 1);
hash.addNode(new Object() { public int hashCode() { return 0; } }, 1);
fail("Expects failed due to internal TreeSet requires comparator or natural ordering.");
}
catch (ClassCastException e) {
info("Expected fail due to internal TreeSet requires comparator or natural ordering: " + e.getMessage());
}
// Constructs hash with explicit node's comparator.
hash = new GridConsistentHash<>(new Comparator<Object>() {
@Override public int compare(Object o1, Object o2) {
// Such comparator is invalid for production code, but acceptable for current test purposes.
return System.identityHashCode(o1) - System.identityHashCode(o2);
}
}, null);
// Add several objects with the same hash into consistent hash with explicit comparator.
hash.addNode(new Object() { public int hashCode() { return 0; } }, 1);
hash.addNode(new Object() { public int hashCode() { return 0; } }, 1);
info("Expected pass due to internal TreeSet has explicit comparator.");
}
/**
*
*/
public void testOneNode() {
GridConsistentHash<UUID> hash = new GridConsistentHash<>();
UUID nodeId = UUID.randomUUID();
initialize(hash, REPLICAS, nodeId);
Collection<UUID> id = hash.nodes("a", 2, F.asList(nodeId));
assertFalse(F.isEmpty(id));
assertEquals(1, id.size());
assertEquals(nodeId, id.iterator().next());
}
/**
*
*/
public void testHistory() {
for (int i = NODES; i-- > 0; ) {
GridConsistentHash<UUID> hash = new GridConsistentHash<>();
UUID[] nodes = nodes(i + 1);
initialize(hash, REPLICAS, nodes);
Collection<UUID> selected = new HashSet<>();
for (int j = i + 1; j-- > 0;) {
String key = UUID.randomUUID().toString();
selected.add(hash.node(key));
hash.removeNode(nodes[j]);
}
info("Number of history nodes for topology [history=" + selected.size() +
", topology=" + (i + 1) + ", selected=" + selected + ']');
}
}
/**
* @param msg Message.
* @param c Collection.
*/
private void info(String msg, Collection c) {
info(msg + " [size=" + c.size() + ", col=" + c + ']');
}
/**
* @param nodes Nodes.
* @return Nodes.
*/
private UUID[] nodes(int nodes) {
UUID[] ids = new UUID[nodes];
for (int i = 0; i < nodes; i++)
ids[i] = UUID.randomUUID();
return ids;
}
/**
* @param hash Hash.
* @param replicas Replicas.
* @param nodes Nodes.
* @return Runnable.
*/
private Runnable initializer(final GridConsistentHash<UUID> hash, final int replicas, final UUID[] nodes) {
return new Runnable() {
@Override public void run() {
initialize(hash, replicas, nodes);
}
};
}
/**
* @param hash Hash.
* @param keys Keys.
* @return Runnable.
*/
private Runnable hasher(final GridConsistentHash<UUID> hash, final String[] keys) {
return new Runnable() {
@Override public void run() {
for (String k : keys) {
assert hash.node(k) != null;
}
}
};
}
/**
* @param hash Hash.
* @param cnts Counts.
* @param mappings Mappings.
* @param keys Keys.
*/
private void hash(GridConsistentHash<UUID> hash, Map<UUID, AtomicInteger> cnts, Map<String, UUID> mappings,
String[] keys) {
for (String k : keys) {
UUID id = hash.node(k);
assert id != null;
AtomicInteger i = cnts.get(id);
if (i == null)
cnts.put(id, i = new AtomicInteger());
i.incrementAndGet();
mappings.put(k, id);
}
}
/**
*
* @param m1 Map 1.
* @param m2 Map 2.
* @param keys Keys.
* @return Reassignment count.
*/
private int compare(Map<String, UUID> m1, Map<String, UUID> m2, String[] keys) {
int cnt = 0;
// Check reassignment percentages.
for (String key : keys) {
UUID id1 = m1.get(key);
UUID id2 = m2.get(key);
assert id1 != null;
assert id2 != null;
if (!id1.equals(id2))
cnt++;
}
return cnt;
}
/**
* @param cnt Number of keys to create.
* @return Array of keys.
*/
private String[] keys(int cnt) {
String[] keys = new String[cnt];
for (int i = 0; i < cnt; i++)
keys[i] = UUID.randomUUID().toString();
return keys;
}
}