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/*
* 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.zookeeper.server.quorum.flexible;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Properties;
import java.util.Set;
import org.apache.zookeeper.server.quorum.QuorumPeer.LearnerType;
import org.apache.zookeeper.server.quorum.QuorumPeer.QuorumServer;
import org.apache.zookeeper.server.quorum.QuorumPeerConfig.ConfigException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* This class implements a validator for majority quorums. The implementation is
* straightforward.
*
*/
public class QuorumMaj implements QuorumVerifier {
private static final Logger LOG = LoggerFactory.getLogger(QuorumMaj.class);
private Map<Long, QuorumServer> allMembers = new HashMap<>();
private Map<Long, QuorumServer> votingMembers = new HashMap<>();
private Map<Long, QuorumServer> observingMembers = new HashMap<>();
private long version = 0;
protected int half;
public int hashCode() {
assert false : "hashCode not designed";
return 42; // any arbitrary constant will do
}
public boolean equals(Object o) {
if (!(o instanceof QuorumMaj)) {
return false;
}
QuorumMaj qm = (QuorumMaj) o;
if (qm.getVersion() == version) {
return true;
}
if (allMembers.size() != qm.getAllMembers().size()) {
return false;
}
for (QuorumServer qs : allMembers.values()) {
QuorumServer qso = qm.getAllMembers().get(qs.id);
if (qso == null || !qs.equals(qso)) {
return false;
}
}
return true;
}
/**
* Defines a majority to avoid computing it every time.
*
*/
public QuorumMaj(Map<Long, QuorumServer> allMembers) {
this.allMembers = allMembers;
for (QuorumServer qs : allMembers.values()) {
if (qs.type == LearnerType.PARTICIPANT) {
votingMembers.put(Long.valueOf(qs.id), qs);
} else {
observingMembers.put(Long.valueOf(qs.id), qs);
}
}
half = votingMembers.size() / 2;
}
public QuorumMaj(Properties props) throws ConfigException {
for (Entry<Object, Object> entry : props.entrySet()) {
String key = entry.getKey().toString();
String value = entry.getValue().toString();
if (key.startsWith("server.")) {
int dot = key.indexOf('.');
long sid = Long.parseLong(key.substring(dot + 1));
QuorumServer qs = new QuorumServer(sid, value);
allMembers.put(Long.valueOf(sid), qs);
if (qs.type == LearnerType.PARTICIPANT) {
votingMembers.put(Long.valueOf(sid), qs);
} else {
observingMembers.put(Long.valueOf(sid), qs);
}
} else if (key.equals("version")) {
version = Long.parseLong(value, 16);
}
}
half = votingMembers.size() / 2;
}
/**
* Returns weight of 1 by default.
*
* @param id
*/
public long getWeight(long id) {
return 1;
}
public String toString() {
StringBuilder sw = new StringBuilder();
for (QuorumServer member : getAllMembers().values()) {
String key = "server." + member.id;
String value = member.toString();
sw.append(key);
sw.append('=');
sw.append(value);
sw.append('\n');
}
String hexVersion = Long.toHexString(version);
sw.append("version=");
sw.append(hexVersion);
return sw.toString();
}
/**
* Verifies if a set is a majority. Assumes that ackSet contains acks only
* from votingMembers
*/
public boolean containsQuorum(Set<Long> ackSet) {
return (ackSet.size() > half);
}
public Map<Long, QuorumServer> getAllMembers() {
return allMembers;
}
public Map<Long, QuorumServer> getVotingMembers() {
return votingMembers;
}
public Map<Long, QuorumServer> getObservingMembers() {
return observingMembers;
}
public long getVersion() {
return version;
}
public void setVersion(long ver) {
version = ver;
}
}
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