Add option to use Hazelcast as datastore for development environment.

This patch will set the default backend as Hazelcast.
To use RAMCloud as backend data store, add -Dnet.onrc.onos.datastore.backend=ramcloud to java option.

- ClientMode: Use existing Hazelcast Instance if it exist.
  - map name starting with datastore:// is now configured to be strong consistent

- add main for manual testing
- follow PMD,etc. where easily possible

- make HZClient Singleton

Change-Id: Ibe2afc3bfddfd7fd567c91477c16cd679fc543d4
diff --git a/src/main/java/net/onrc/onos/datastore/hazelcast/HZClient.java b/src/main/java/net/onrc/onos/datastore/hazelcast/HZClient.java
new file mode 100644
index 0000000..2c2b3a4
--- /dev/null
+++ b/src/main/java/net/onrc/onos/datastore/hazelcast/HZClient.java
@@ -0,0 +1,345 @@
+package net.onrc.onos.datastore.hazelcast;
+
+import java.io.FileNotFoundException;
+import java.util.Collection;
+import java.util.List;
+
+import net.onrc.onos.datastore.IKVClient;
+import net.onrc.onos.datastore.IKVTable;
+import net.onrc.onos.datastore.IKVTable.IKVEntry;
+import net.onrc.onos.datastore.IKVTableID;
+import net.onrc.onos.datastore.IMultiEntryOperation;
+import net.onrc.onos.datastore.IMultiEntryOperation.OPERATION;
+import net.onrc.onos.datastore.IMultiEntryOperation.STATUS;
+import net.onrc.onos.datastore.ObjectDoesntExistException;
+import net.onrc.onos.datastore.ObjectExistsException;
+import net.onrc.onos.datastore.WrongVersionException;
+import net.onrc.onos.datastore.hazelcast.HZTable.VersionedValue;
+import net.onrc.onos.datastore.internal.IModifiableMultiEntryOperation;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.hazelcast.client.HazelcastClient;
+import com.hazelcast.client.config.ClientConfig;
+import com.hazelcast.config.Config;
+import com.hazelcast.config.FileSystemXmlConfig;
+import com.hazelcast.config.MapConfig;
+import com.hazelcast.config.SerializationConfig;
+import com.hazelcast.core.Hazelcast;
+import com.hazelcast.core.HazelcastInstance;
+import com.hazelcast.core.IMap;
+
+public class HZClient implements IKVClient {
+    private static final Logger log = LoggerFactory.getLogger(HZClient.class);
+
+    static final long VERSION_NONEXISTENT = 0L;
+
+    private static final String MAP_PREFIX = "datastore://";
+
+    // make this path configurable
+    private static final String BASE_CONFIG_FILENAME = System.getProperty("net.onrc.onos.datastore.hazelcast.baseConfig", "conf/hazelcast.xml");
+    private static boolean useClientMode = Boolean.parseBoolean(System.getProperty("net.onrc.onos.datastore.hazelcast.clientMode", "true"));
+
+    // Note: xml configuration will overwrite this value if present
+    private static int backupCount = Integer.valueOf(System.getProperty("net.onrc.onos.datastore.hazelcast.backupCount", "3"));
+
+    private final HazelcastInstance hazelcastInstance;
+
+    private static final HZClient THE_INSTANCE = new HZClient();
+
+    public static HZClient getClient() {
+	return THE_INSTANCE;
+    }
+
+    private HZClient() {
+	hazelcastInstance = getHZinstance(BASE_CONFIG_FILENAME);
+    }
+
+    private static HazelcastInstance getHZinstance(final String hazelcastConfigFileName) {
+	Config baseHzConfig = null;
+	try {
+	    baseHzConfig = new FileSystemXmlConfig(hazelcastConfigFileName);
+	} catch (FileNotFoundException e) {
+	    log.error("Error opening Hazelcast XML configuration. File not found: " + hazelcastConfigFileName, e);
+	    throw new Error("Cannot find Hazelcast configuration: " + hazelcastConfigFileName , e);
+	}
+
+	// use xml config if present, if not use System.property
+	MapConfig mapConfig = baseHzConfig.getMapConfigs().get(MAP_PREFIX + "*");
+	if (mapConfig != null) {
+	    backupCount = mapConfig.getBackupCount();
+	}
+
+	HazelcastInstance instance = null;
+	if (useClientMode) {
+	    log.info("Configuring Hazelcast datastore as Client mode");
+	    ClientConfig clientConfig = new ClientConfig();
+	    final int port = baseHzConfig.getNetworkConfig().getPort();
+
+	    String server = System.getProperty("net.onrc.onos.datastore.hazelcast.client.server", "localhost");
+	    clientConfig.addAddress(server + ":" + port);
+
+	    // copy group config from base Hazelcast configuration
+	    clientConfig.getGroupConfig().setName(baseHzConfig.getGroupConfig().getName());
+	    clientConfig.getGroupConfig().setPassword(baseHzConfig.getGroupConfig().getPassword());
+
+	    // TODO We probably need to figure out what else need to be
+	    // derived from baseConfig
+
+	    registerSerializer(clientConfig.getSerializationConfig());
+
+	    log.info("Starting Hazelcast datastore client for [{}]", clientConfig.getAddressList());
+
+	    try {
+		instance = HazelcastClient.newHazelcastClient(clientConfig);
+		if (!instance.getCluster().getMembers().isEmpty()) {
+		    log.debug("Members in cluster: " + instance.getCluster().getMembers());
+		    return instance;
+		}
+		log.info("Failed to find cluster member, falling back to Instance mode");
+	    } catch (IllegalStateException e) {
+		log.info("Failed to initialize HazelcastClient, falling back to Instance mode");
+	    }
+	    useClientMode = false;
+	    instance = null;
+	}
+	log.info("Configuring Hazelcast datastore as Instance mode");
+
+	// To run 2 Hazelcast instance in 1 JVM,
+	// we probably need to something like below
+	//int port = hazelcastConfig.getNetworkConfig().getPort();
+	//hazelcastConfig.getNetworkConfig().setPort(port+1);
+
+	registerSerializer(baseHzConfig.getSerializationConfig());
+
+	return Hazelcast.newHazelcastInstance(baseHzConfig);
+    }
+
+    /**
+     * Register serializer for VersionedValue class used to imitate value version.
+     * @param config
+     */
+    private static void registerSerializer(final SerializationConfig config) {
+	config.addDataSerializableFactoryClass(
+		    VersionedValueSerializableFactory.FACTORY_ID,
+		    VersionedValueSerializableFactory.class);
+    }
+
+    @Override
+    public IKVTable getTable(final String tableName) {
+	IMap<byte[], VersionedValue> map = hazelcastInstance.getMap(MAP_PREFIX + tableName);
+
+	if (!useClientMode) {
+	    // config only available in Instance Mode
+	    // Client Mode must rely on hazelcast.xml to be properly configured.
+	    MapConfig config = hazelcastInstance.getConfig().getMapConfig(MAP_PREFIX + tableName);
+	    // config for this map to be strong consistent
+	    if (config.isReadBackupData()) {
+		config.setReadBackupData(false);
+	    }
+	    if (config.isNearCacheEnabled()) {
+		config.getNearCacheConfig().setMaxSize(0);
+	    }
+
+	    if (config.getBackupCount() != backupCount) {
+		config.setAsyncBackupCount(0);
+		config.setBackupCount(backupCount);
+	    }
+	}
+
+	return new HZTable(tableName, map);
+    }
+
+    @Override
+    public void dropTable(final IKVTable table) {
+	((HZTable) table).getBackendMap().clear();
+    }
+
+    @Override
+    public long create(final IKVTableID tableId, final byte[] key, final byte[] value)
+            throws ObjectExistsException {
+	IKVTable table = (IKVTable) tableId;
+	return table.create(key, value);
+    }
+
+    @Override
+    public long forceCreate(final IKVTableID tableId, final byte[] key, final byte[] value) {
+	IKVTable table = (IKVTable) tableId;
+	return table.forceCreate(key, value);
+    }
+
+    @Override
+    public IKVEntry read(final IKVTableID tableId, final byte[] key)
+            throws ObjectDoesntExistException {
+	IKVTable table = (IKVTable) tableId;
+	return table.read(key);
+    }
+
+    @Override
+    public long update(final IKVTableID tableId, final byte[] key, final byte[] value,
+            final long version) throws ObjectDoesntExistException,
+            WrongVersionException {
+	IKVTable table = (IKVTable) tableId;
+	return table.update(key, value, version);
+    }
+
+    @Override
+    public long update(final IKVTableID tableId, final byte[] key, final byte[] value)
+            throws ObjectDoesntExistException {
+	IKVTable table = (IKVTable) tableId;
+	return table.update(key, value);
+    }
+
+    @Override
+    public long delete(final IKVTableID tableId, final byte[] key, final long version)
+            throws ObjectDoesntExistException, WrongVersionException {
+	IKVTable table = (IKVTable) tableId;
+	return table.delete(key, version);
+    }
+
+    @Override
+    public long forceDelete(final IKVTableID tableId, final byte[] key) {
+	IKVTable table = (IKVTable) tableId;
+	return table.forceDelete(key);
+    }
+
+    @Override
+    public Iterable<IKVEntry> getAllEntries(final IKVTableID tableId) {
+	IKVTable table = (IKVTable) tableId;
+	return table.getAllEntries();
+    }
+
+    @Override
+    public IMultiEntryOperation createOp(final IKVTableID tableId, final byte[] key,
+            final byte[] value) {
+	return new HZMultiEntryOperation((HZTable) tableId, key, value, HZClient.VERSION_NONEXISTENT, OPERATION.CREATE);
+    }
+
+    @Override
+    public IMultiEntryOperation forceCreateOp(final IKVTableID tableId, final byte[] key,
+            final byte[] value) {
+	return new HZMultiEntryOperation((HZTable) tableId, key, value, HZClient.VERSION_NONEXISTENT, OPERATION.FORCE_CREATE);
+    }
+
+    @Override
+    public IMultiEntryOperation readOp(final IKVTableID tableId, final byte[] key) {
+	return new HZMultiEntryOperation((HZTable) tableId, key, OPERATION.READ);
+    }
+
+    @Override
+    public IMultiEntryOperation updateOp(final IKVTableID tableId, final byte[] key,
+            final byte[] value, final long version) {
+	return new HZMultiEntryOperation((HZTable) tableId, key, value, version, OPERATION.UPDATE);
+    }
+
+    @Override
+    public IMultiEntryOperation deleteOp(final IKVTableID tableId, final byte[] key,
+            final byte[] value, final long version) {
+	return new HZMultiEntryOperation((HZTable) tableId, key, value, version, OPERATION.DELETE);
+    }
+
+    @Override
+    public IMultiEntryOperation forceDeleteOp(final IKVTableID tableId, final byte[] key) {
+	return new HZMultiEntryOperation((HZTable) tableId, key, OPERATION.FORCE_DELETE);
+    }
+
+    @Override
+    public boolean multiDelete(final Collection<IMultiEntryOperation> ops) {
+	boolean failExists = false;
+	for (IMultiEntryOperation op : ops) {
+	    HZMultiEntryOperation mop = (HZMultiEntryOperation) op;
+	    switch (mop.getOperation()) {
+	    case DELETE:
+		try {
+		    final long version = delete(mop.getTableId(), mop.getKey(), mop.getVersion());
+		    mop.setVersion(version);
+		    mop.setStatus(STATUS.SUCCESS);
+		} catch (ObjectDoesntExistException | WrongVersionException e) {
+		    log.error(mop + " failed.", e);
+		    mop.setStatus(STATUS.FAILED);
+                    failExists = true;
+		}
+		break;
+	    case FORCE_DELETE:
+		final long version = forceDelete(mop.getTableId(), mop.getKey());
+		mop.setVersion(version);
+		mop.setStatus(STATUS.SUCCESS);
+		break;
+	    default:
+		throw new UnsupportedOperationException(mop.toString());
+	    }
+	}
+	return failExists;
+    }
+
+    @Override
+    public boolean multiWrite(final List<IMultiEntryOperation> ops) {
+	// there may be room to batch to improve performance
+	boolean failExists = false;
+	for (IMultiEntryOperation op : ops) {
+	    IModifiableMultiEntryOperation mop = (IModifiableMultiEntryOperation) op;
+	    switch (mop.getOperation()) {
+	    case CREATE:
+		try {
+		    long version = create(mop.getTableId(), mop.getKey(), mop.getValue());
+		    mop.setVersion(version);
+		    mop.setStatus(STATUS.SUCCESS);
+		} catch (ObjectExistsException e) {
+		    log.error(mop + " failed.", e);
+		    mop.setStatus(STATUS.FAILED);
+		    failExists = true;
+		}
+		break;
+	    case FORCE_CREATE:
+	    {
+		final long version = forceCreate(mop.getTableId(), mop.getKey(), mop.getValue());
+		mop.setVersion(version);
+		mop.setStatus(STATUS.SUCCESS);
+		break;
+	    }
+	    case UPDATE:
+		try {
+		    long version = update(mop.getTableId(), mop.getKey(), mop.getValue(), mop.getVersion());
+		    mop.setVersion(version);
+		    mop.setStatus(STATUS.SUCCESS);
+		} catch (ObjectDoesntExistException | WrongVersionException e) {
+		    log.error(mop + " failed.", e);
+		    mop.setStatus(STATUS.FAILED);
+		    failExists = true;
+		}
+		break;
+	    default:
+		throw new UnsupportedOperationException(mop.toString());
+	    }
+	}
+	return failExists;
+    }
+
+    @Override
+    public boolean multiRead(final Collection<IMultiEntryOperation> ops) {
+	boolean failExists = false;
+	for (IMultiEntryOperation op : ops) {
+	    IModifiableMultiEntryOperation mop = (IModifiableMultiEntryOperation) op;
+	    HZTable table = (HZTable) op.getTableId();
+	    ((HZMultiEntryOperation) mop.getActualOperation()).setFuture(table.getBackendMap().getAsync(op.getKey()));
+	}
+	for (IMultiEntryOperation op : ops) {
+	    IModifiableMultiEntryOperation mop = (IModifiableMultiEntryOperation) op;
+	    if (mop.hasSucceeded()) {
+		// status update is already done, nothing to do.
+	    } else {
+		failExists = true;
+	    }
+	}
+
+	return failExists;
+    }
+
+    @Override
+    public long VERSION_NONEXISTENT() {
+	return VERSION_NONEXISTENT;
+    }
+
+
+}
diff --git a/src/main/java/net/onrc/onos/datastore/hazelcast/HZMultiEntryOperation.java b/src/main/java/net/onrc/onos/datastore/hazelcast/HZMultiEntryOperation.java
new file mode 100644
index 0000000..1da7f1a
--- /dev/null
+++ b/src/main/java/net/onrc/onos/datastore/hazelcast/HZMultiEntryOperation.java
@@ -0,0 +1,162 @@
+package net.onrc.onos.datastore.hazelcast;
+
+import java.util.concurrent.CancellationException;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Future;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import net.onrc.onos.datastore.IKVTableID;
+import net.onrc.onos.datastore.IMultiEntryOperation;
+import net.onrc.onos.datastore.hazelcast.HZTable.VersionedValue;
+import net.onrc.onos.datastore.internal.IModifiableMultiEntryOperation;
+import net.onrc.onos.datastore.utils.ByteArrayUtil;
+
+public class HZMultiEntryOperation implements IMultiEntryOperation, IModifiableMultiEntryOperation {
+    private static final Logger log = LoggerFactory.getLogger(HZMultiEntryOperation.class);
+
+    private final HZTable table;
+    private final byte[] key;
+    protected final OPERATION operation;
+    private STATUS status;
+
+    // for read op
+    private Future<VersionedValue> future;
+    // for write op
+    private VersionedValue writeValue;
+
+    /**
+     * Constructor for Read/ForceDelete Operation.
+     * @param table
+     * @param key
+     * @param operation
+     */
+    public HZMultiEntryOperation(final HZTable table, final byte[] key, final OPERATION operation) {
+	this.table = table;
+	this.key = key;
+	this.status = STATUS.NOT_EXECUTED;
+	this.operation = operation;
+
+	this.future = null;
+	this.writeValue = null;
+    }
+
+    /**
+     * Constructor for Other Operations.
+     * @param table
+     * @param key
+     * @param value
+     * @param version
+     * @param operation
+     */
+    public HZMultiEntryOperation(final HZTable table, final byte[] key, final byte[] value, final long version, final OPERATION operation) {
+	this.table = table;
+	this.key = key;
+	this.status = STATUS.NOT_EXECUTED;
+	this.operation = operation;
+
+	this.future = null;
+	this.writeValue = new VersionedValue(value, version);
+    }
+
+    @Override
+    public boolean hasSucceeded() {
+
+	VersionedValue value = get();
+	return (value != null) && (this.status == STATUS.SUCCESS);
+    }
+
+    @Override
+    public STATUS getStatus() {
+	get();
+	return status;
+    }
+
+    @Override
+    public IKVTableID getTableId() {
+	return table;
+    }
+
+    @Override
+    public byte[] getKey() {
+	return key;
+    }
+
+    @Override
+    public byte[] getValue() {
+	if (future != null) {
+	    VersionedValue value = get();
+	    return value.getValue();
+	}
+	return writeValue.getValue();
+    }
+
+    @Override
+    public long getVersion() {
+	if (future != null) {
+	    VersionedValue value = get();
+	    return value.getVersion();
+	}
+	return writeValue.getVersion();
+    }
+
+    @Override
+    public OPERATION getOperation() {
+	return operation;
+    }
+
+    /**
+     * Evaluate Future object and set Status and Value+Version.
+     * @return the value read or null on failure.
+     */
+    private VersionedValue get() {
+        try {
+            VersionedValue value = future.get();
+            setValue(value.getValue(), value.getVersion());
+            setStatus(STATUS.SUCCESS);
+            return value;
+        } catch (CancellationException | InterruptedException | ExecutionException e) {
+            log.error(this + " has failed.", e);
+            setStatus(STATUS.FAILED);
+            return null;
+        }
+    }
+
+    @Override
+    public void setValue(final byte[] value, final long version) {
+	writeValue = new VersionedValue(value, version);
+	setVersion(version);
+    }
+
+    @Override
+    public void setVersion(final long version) {
+	if (future != null) {
+	    // no-op on read
+	}
+	if (writeValue == null) {
+	    writeValue = new VersionedValue(null, version);
+	}
+    }
+
+    @Override
+    public void setStatus(final STATUS status) {
+	this.status = status;
+    }
+
+    @Override
+    public IModifiableMultiEntryOperation getActualOperation() {
+	return this;
+    }
+
+    void setFuture(final Future<VersionedValue> future) {
+        this.future = future;
+    }
+
+    @Override
+    public String toString() {
+	return "[HZMultiEntryOperation table=" + table + ", key="
+	        + ByteArrayUtil.toHexStringBuffer(key, ":") + ", operation=" + operation
+	        + ", status=" + status + ", writeValue=" + writeValue + "]";
+    }
+}
diff --git a/src/main/java/net/onrc/onos/datastore/hazelcast/HZTable.java b/src/main/java/net/onrc/onos/datastore/hazelcast/HZTable.java
new file mode 100644
index 0000000..ec98349
--- /dev/null
+++ b/src/main/java/net/onrc/onos/datastore/hazelcast/HZTable.java
@@ -0,0 +1,325 @@
+package net.onrc.onos.datastore.hazelcast;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicLong;
+
+import net.onrc.onos.datastore.IKVTable;
+import net.onrc.onos.datastore.IKVTableID;
+import net.onrc.onos.datastore.ObjectDoesntExistException;
+import net.onrc.onos.datastore.ObjectExistsException;
+import net.onrc.onos.datastore.WrongVersionException;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.hazelcast.core.IMap;
+import com.hazelcast.nio.ObjectDataInput;
+import com.hazelcast.nio.ObjectDataOutput;
+import com.hazelcast.nio.serialization.IdentifiedDataSerializable;
+
+public class HZTable implements IKVTable, IKVTableID {
+    @SuppressWarnings("unused")
+    private static final Logger log = LoggerFactory.getLogger(HZTable.class);
+
+    // not sure how strict this should be managed
+    private static final AtomicLong  initialVersion = new AtomicLong(HZClient.VERSION_NONEXISTENT);
+
+    /**
+     * generate a new initial version for an entry.
+     * @return initial value
+     */
+    protected static long getInitialVersion() {
+	long version = initialVersion.incrementAndGet();
+	if (version == HZClient.VERSION_NONEXISTENT) {
+	    // used up whole 64bit space?
+	    version = initialVersion.incrementAndGet();
+	}
+	return version;
+    }
+
+    /**
+     * increment version, avoiding VERSION_NONEXISTENT.
+     * @param version
+     * @return
+     */
+    protected static long getNextVersion(final long version) {
+	long nextVersion = version + 1;
+	if (nextVersion == HZClient.VERSION_NONEXISTENT) {
+	    ++nextVersion;
+	}
+	return nextVersion;
+    }
+
+    static class VersionedValue implements IdentifiedDataSerializable {
+	private static final long serialVersionUID = -3149375966890712708L;
+
+	private byte[] value;
+	private long version;
+
+	protected VersionedValue() {
+	    value = new byte[0];
+	    version = HZClient.VERSION_NONEXISTENT;
+	}
+
+	public VersionedValue(final byte[] value, final long version) {
+	    this.value = value;
+	    this.version = version;
+	}
+
+	public byte[] getValue() {
+	    return value;
+	}
+
+	public long getVersion() {
+	    return version;
+	}
+
+	public void setValue(final byte[] value) {
+	    this.value = value;
+	}
+
+	public void setNextVersion() {
+	    this.version = getNextVersion(this.version);
+	}
+
+	@Override
+	public void writeData(final ObjectDataOutput out) throws IOException {
+	    out.writeLong(version);
+	    out.writeInt(value.length);
+	    if (value.length > 0) {
+		out.write(value);
+	    }
+	}
+
+	@Override
+	public void readData(final ObjectDataInput in) throws IOException {
+	    version = in.readLong();
+	    final int valueLen = in.readInt();
+	    value = new byte[valueLen];
+	    in.readFully(value);
+	}
+
+	@Override
+	public int getFactoryId() {
+	    return VersionedValueSerializableFactory.FACTORY_ID;
+	}
+
+	@Override
+	public int getId() {
+	    return VersionedValueSerializableFactory.VERSIONED_VALUE_ID;
+	}
+
+	@Override
+	public int hashCode() {
+	    final int prime = 31;
+	    int result = 1;
+	    result = prime * result + (int) (version ^ (version >>> 32));
+	    result = prime * result + Arrays.hashCode(value);
+	    return result;
+	}
+
+	@Override
+	public boolean equals(final Object obj) {
+	    if (this == obj) {
+		return true;
+	    }
+	    if (obj == null) {
+		return false;
+	    }
+	    if (getClass() != obj.getClass()) {
+		return false;
+	    }
+	    VersionedValue other = (VersionedValue) obj;
+	    if (version != other.version) {
+		return false;
+	    }
+	    if (!Arrays.equals(value, other.value)) {
+		return false;
+	    }
+	    return true;
+	}
+    }
+
+    // TODO Refactor and extract common parts
+    public static class Entry implements IKVEntry {
+	final byte[] key;
+	byte[] value;
+	long version;
+
+	public Entry(final byte[] key, final byte[] value, final long version) {
+	    this.key = key;
+	    this.setValue(value);
+	    this.setVersion(version);
+	}
+
+	public Entry(final byte[] key) {
+	    this(key, null, HZClient.VERSION_NONEXISTENT);
+	}
+
+	@Override
+	public byte[] getKey() {
+	    return key;
+	}
+
+	@Override
+	public byte[] getValue() {
+	    return value;
+	}
+
+	@Override
+	public long getVersion() {
+	    return version;
+	}
+
+	void setValue(final byte[] value) {
+	    this.value = value;
+	}
+
+	void setVersion(final long version) {
+	    this.version = version;
+	}
+    }
+
+
+
+    private final String mapName;
+    private final IMap<byte[], VersionedValue> map;
+
+    public HZTable(final String mapName, final IMap<byte[], VersionedValue> map) {
+	this.mapName = mapName;
+	this.map = map;
+    }
+
+    @Override
+    public String getTableName() {
+	return mapName;
+    }
+
+    @Override
+    public IKVTableID getTableId() {
+	return this;
+    }
+
+    @Override
+    public long create(final byte[] key, final byte[] value) throws ObjectExistsException {
+	final long version = getInitialVersion();
+	VersionedValue existing = map.putIfAbsent(key, new VersionedValue(value, version));
+	if (existing != null) {
+	    throw new ObjectExistsException(this, key);
+	}
+	return version;
+    }
+
+    @Override
+    public long forceCreate(final byte[] key, final byte[] value) {
+	final long version = getInitialVersion();
+	map.set(key, new VersionedValue(value, version));
+	return version;
+    }
+
+    @Override
+    public IKVEntry read(final byte[] key) throws ObjectDoesntExistException {
+	final VersionedValue value = map.get(key);
+	if (value == null) {
+	    throw new ObjectDoesntExistException(this, key);
+	}
+	return new Entry(key, value.getValue(), value.getVersion());
+    }
+
+    @Override
+    public long update(final byte[] key, final byte[] value, final long version)
+            throws ObjectDoesntExistException, WrongVersionException {
+
+	try {
+	    map.lock(key);
+	    final VersionedValue oldValue = map.get(key);
+	    if (oldValue == null) {
+		throw new ObjectDoesntExistException(this, key);
+	    }
+	    if (oldValue.getVersion() != version) {
+		throw new WrongVersionException(this, key, version, oldValue.getVersion());
+	    }
+	    final long nextVersion = getNextVersion(version);
+	    map.set(key, new VersionedValue(value, nextVersion));
+	    return nextVersion;
+	} finally {
+	    map.unlock(key);
+	}
+    }
+
+    @Override
+    public long update(final byte[] key, final byte[] value)
+            throws ObjectDoesntExistException {
+
+	try {
+	    map.lock(key);
+	    final VersionedValue valueInMap = map.get(key);
+	    if (valueInMap == null) {
+		throw new ObjectDoesntExistException(this, key);
+	    }
+	    valueInMap.setValue(value);
+	    valueInMap.setNextVersion();
+	    map.set(key, valueInMap);
+	    return valueInMap.getVersion();
+	} finally {
+	    map.unlock(key);
+	}
+    }
+
+    @Override
+    public long delete(final byte[] key, final long version)
+            throws ObjectDoesntExistException, WrongVersionException {
+
+	try {
+	    map.lock(key);
+	    final VersionedValue oldValue = map.get(key);
+	    if (oldValue == null) {
+		throw new ObjectDoesntExistException(this, key);
+	    }
+	    if (oldValue.getVersion() != version) {
+		throw new WrongVersionException(this, key, version, oldValue.getVersion());
+	    }
+	    map.delete(key);
+	    return oldValue.getVersion();
+	} finally {
+	    map.unlock(key);
+	}
+    }
+
+    @Override
+    public long forceDelete(final byte[] key) {
+	final VersionedValue valueInMap = map.remove(key);
+	if (valueInMap == null) {
+	    return HZClient.VERSION_NONEXISTENT;
+	}
+	return valueInMap.getVersion();
+    }
+
+    @Override
+    public Iterable<IKVEntry> getAllEntries() {
+	final Set<IMap.Entry<byte[], VersionedValue>> entries = map.entrySet();
+	List<IKVEntry> entryList = new ArrayList<IKVTable.IKVEntry>(entries.size());
+	for (IMap.Entry<byte[], VersionedValue> entry : entries) {
+	    entryList.add(new Entry(entry.getKey(), entry.getValue().getValue(), entry.getValue().getVersion()));
+	}
+	return entryList;
+    }
+
+    @Override
+    public String toString() {
+	return "[HZTable " + mapName + "]";
+    }
+
+    IMap<byte[], VersionedValue> getBackendMap() {
+	return this.map;
+    }
+
+    @Override
+    public long VERSION_NONEXISTENT() {
+	return HZClient.VERSION_NONEXISTENT;
+    }
+}
diff --git a/src/main/java/net/onrc/onos/datastore/hazelcast/VersionedValueSerializableFactory.java b/src/main/java/net/onrc/onos/datastore/hazelcast/VersionedValueSerializableFactory.java
new file mode 100644
index 0000000..a4e7fb9
--- /dev/null
+++ b/src/main/java/net/onrc/onos/datastore/hazelcast/VersionedValueSerializableFactory.java
@@ -0,0 +1,25 @@
+package net.onrc.onos.datastore.hazelcast;
+
+
+import com.hazelcast.nio.serialization.DataSerializableFactory;
+import com.hazelcast.nio.serialization.IdentifiedDataSerializable;
+
+public class VersionedValueSerializableFactory implements
+        DataSerializableFactory {
+    // revisit these magic numbers
+    public static final int FACTORY_ID = 1;
+
+    public static final int VERSIONED_VALUE_ID = 1;
+
+    @Override
+    public IdentifiedDataSerializable create(final int typeId) {
+	switch (typeId) {
+	case VERSIONED_VALUE_ID:
+	    return new HZTable.VersionedValue();
+
+	default:
+		return null;
+	}
+    }
+
+}