org.shoal.ha.mapper.DefaultKeyMapper Maven / Gradle / Ivy
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package org.shoal.ha.mapper;
import org.glassfish.ha.store.api.HashableKey;
import org.shoal.ha.cache.api.ShoalCacheLoggerConstants;
import org.shoal.ha.group.GroupMemberEventListener;
import java.math.BigInteger;
import java.nio.charset.Charset;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.*;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* @author Mahesh Kannan
*/
public class DefaultKeyMapper
implements KeyMapper, GroupMemberEventListener {
Logger _logger = Logger.getLogger(ShoalCacheLoggerConstants.CACHE_KEY_MAPPER);
private String myName;
private String groupName;
private ReentrantReadWriteLock.ReadLock rLock;
private ReentrantReadWriteLock.WriteLock wLock;
private volatile String[] members = new String[0];
private volatile String[] previuousAliveAndReadyMembers = new String[0];
private volatile String[] replicaChoices = new String[0];
private static final String _EMPTY_REPLICAS = "";
public DefaultKeyMapper(String myName, String groupName) {
this.myName = myName;
this.groupName = groupName;
ReentrantReadWriteLock rwLock = new ReentrantReadWriteLock();
rLock = rwLock.readLock();
wLock = rwLock.writeLock();
_logger.log(Level.FINE, "DefaultKeyMapper created for: myName: " + myName + "; groupName: " + groupName);
}
protected ReentrantReadWriteLock.ReadLock getReadLock() {
return rLock;
}
protected ReentrantReadWriteLock.WriteLock getWriteLock() {
return wLock;
}
protected String[] getMembers() {
return members;
}
@Override
public String getMappedInstance(String groupName, Object key1) {
int hc = key1.hashCode();
if (key1 instanceof HashableKey) {
HashableKey k = (HashableKey) key1;
hc = k.getHashKey() == null ? hc : k.getHashKey().hashCode();
if (_logger.isLoggable(Level.FINE)) {
_logger.log(Level.FINE, "DefaultKeyMapper.getMappedInstance got a HashableKey "
+ " key = " + key1 + "; key.hc = " + key1.hashCode()
+ "; key.getHashKey() = " + ((HashableKey) key1).getHashKey() + "; key.getHashKey().hc = "
+ (k.getHashKey() == null ? "-" : hc)
+ "; Final hc = " + hc
);
}
}
try {
rLock.lock();
return members.length == 0
? null
: members[Math.abs(hc % members.length)];
} finally {
rLock.unlock();
}
}
@Override
public String getReplicaChoices(String groupName, Object key) {
int hc = getHashCodeForKey(key);
try {
rLock.lock();
return members.length == 0
? _EMPTY_REPLICAS
: replicaChoices[Math.abs(hc % members.length)];
} finally {
rLock.unlock();
}
}
@Override
public String[] getCurrentMembers() {
return members;
}
/*
@Override
public String[] getKeyMappingInfo(String groupName, Object key1) {
int hc = key1.hashCode();
if (key1 instanceof HashableKey) {
HashableKey k = (HashableKey) key1;
hc = k.getHashKey() == null ? hc : k.getHashKey().hashCode();
}
hc = Math.abs(hc);
try {
rLock.lock();
return getKeyMappingInfo(members, hc);
} finally {
rLock.unlock();
}
}
protected String[] getKeyMappingInfo(String[] instances, int hc) {
if (members.length == 0) {
return _EMPTY_TARGETS;
} else if (members.length == 1) {
return new String[] {members[0], null};
} else {
int index = hc % members.length;
return new String[] {members[index], members[(index + 1) % members.length]};
}
}
*/
@Override
public String[] findReplicaInstance(String groupName, Object key1, String keyMappingInfo) {
if (keyMappingInfo != null) {
return keyMappingInfo.split(":");
} else {
int hc = key1.hashCode();
if (key1 instanceof HashableKey) {
HashableKey k = (HashableKey) key1;
hc = k.getHashKey() == null ? hc : k.getHashKey().hashCode();
}
try {
rLock.lock();
return previuousAliveAndReadyMembers.length == 0
? new String[] {_EMPTY_REPLICAS}
: new String[] {previuousAliveAndReadyMembers[Math.abs(hc % previuousAliveAndReadyMembers.length)]};
} finally {
rLock.unlock();
}
}
}
@Override
public void onViewChange(String memberName,
Collection readOnlyCurrentAliveAndReadyMembers,
Collection readOnlyPreviousAliveAndReadyMembers,
boolean isJoinEvent) {
try {
wLock.lock();
TreeSet currentMemberSet = new TreeSet();
currentMemberSet.addAll(readOnlyCurrentAliveAndReadyMembers);
currentMemberSet.remove(myName);
members = currentMemberSet.toArray(new String[0]);
int memSz = members.length;
this.replicaChoices = new String[memSz];
if (memSz == 0) {
this.replicaChoices = new String[] {_EMPTY_REPLICAS};
} else {
for (int i=0; i 0; j++) {
sb.append(delim).append(members[index++ % memSz]);
delim = ":";
}
replicaChoices[i] = sb.toString();
}
}
TreeSet previousView = new TreeSet();
previousView.addAll(readOnlyPreviousAliveAndReadyMembers);
if (! isJoinEvent) {
previousView.remove(memberName);
}
previuousAliveAndReadyMembers = previousView.toArray(new String[0]);
if (_logger.isLoggable(Level.FINE)) {
printMemberStates("onViewChange (isJoin: " + isJoinEvent + ")");
}
} finally {
wLock.unlock();
}
}
private int getHashCodeForKey(Object key1) {
int hc = key1.hashCode();
if (key1 instanceof HashableKey) {
HashableKey k = (HashableKey) key1;
hc = k.getHashKey() == null ? hc : k.getHashKey().hashCode();
}
return hc;
}
private static int getDigestHashCode(String val) {
int hc = val.hashCode();
try {
String hcStr = "_" + val.hashCode() + "_";
MessageDigest dig = MessageDigest.getInstance("MD5");
dig.update(hcStr.getBytes(Charset.defaultCharset()));
dig.update(val.getBytes(Charset.defaultCharset()));
dig.update(hcStr.getBytes(Charset.defaultCharset()));
BigInteger bi = new BigInteger(dig.digest());
hc = bi.intValue();
return hc;
} catch (NoSuchAlgorithmException nsaEx) {
hc = val.hashCode();
}
return hc;
}
public void printMemberStates(String message) {
StringBuilder sb = new StringBuilder("DefaultKeyMapper[" + myName + "]." + message + " currentView: ");
String delim = "";
for (String st : members) {
sb.append(delim).append(st);
delim = " : ";
}
sb.append("; previousView ");
delim = "";
for (String st : previuousAliveAndReadyMembers) {
sb.append(delim).append(st);
delim = " : ";
}
sb.append("\n");
int memSz = members.length;
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