[ONOS-2447]RFC7047's API and its implementation and five main tables.

provide RFC7047's API and its implementation, and five main table which
contain Bridge, Controller, Interface, Open_vSwitch and Port 

Change-Id: I9e995a056fd55c986f5866c85ac712f1792cff4f

@@ -26,6 +26,14 @@
             <groupId>org.onosproject</groupId>
             <groupId>org.onosproject</groupId>
             <artifactId>onlab-junit</artifactId>
             <artifactId>onlab-junit</artifactId>
         </dependency>
         </dependency>
+        <dependency>
+          <groupId>io.netty</groupId>
+          <artifactId>netty-buffer</artifactId>
+        </dependency>
+        <dependency>
+          <groupId>io.netty</groupId>
+          <artifactId>netty-handler</artifactId>
+        </dependency>
     </dependencies>
     </dependencies>
 
 
     <build>
     <build>

+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed 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.onosproject.ovsdb.rfc.jsonrpc;
+
+import java.util.List;
+
+import org.onosproject.ovsdb.rfc.message.UpdateNotification;
+
+/**
+ * The callback function interface will be used when the server send to the
+ * client report changes.
+ */
+public interface Callback {
+    /**
+     * The "update" notification is sent by the server to the client to report
+     * changes in tables that are being monitored following a "*monitor"
+     * request.
+     * @param updateNotification the information of the update
+     */
+    void update(UpdateNotification updateNotification);
+
+    /**
+     * The "locked" notification is provided to notify a client that it has been
+     * granted a lock that it had previously requested with the "lock" method.
+     * @param ids the locked ids
+     */
+    void locked(List<String> ids);
+
+    /**
+     * The "stolen" notification is provided to notify a client, which had
+     * previously obtained a lock, that another client has stolen ownership of
+     * that lock.
+     * @param ids the stolen ids
+     */
+    void stolen(List<String> ids);
+
+}

+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed 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.onosproject.ovsdb.rfc.jsonrpc;
+
+import java.util.Stack;
+
+/**
+ * Context for decode parameters.
+ */
+public class JsonReadContext {
+    private Stack<Byte> bufStack;
+    private boolean isStartMatch;
+    private int lastReadBytes;
+
+    /**
+     * Constructs a JsonReadContext object. This class only need initial
+     * parameter value for the readToJsonNode method of JsonRpcReaderUtil
+     * entity.
+     */
+    public JsonReadContext() {
+        bufStack = new Stack<Byte>();
+        isStartMatch = false;
+        lastReadBytes = 0;
+    }
+
+    /**
+     * Return bufStack.
+     * @return bufStack
+     */
+    public Stack<Byte> getBufStack() {
+        return bufStack;
+    }
+
+    /**
+     * Set bufStack, used for match the braces and double quotes.
+     * @param bufStack Stack of Byte
+     */
+    public void setBufStack(Stack<Byte> bufStack) {
+        this.bufStack = bufStack;
+    }
+
+    /**
+     * Return isStartMatch.
+     * @return isStartMatch
+     */
+    public boolean isStartMatch() {
+        return isStartMatch;
+    }
+
+    /**
+     * Set isStartMatch.
+     * @param isStartMatch mark whether the matching has started
+     */
+    public void setStartMatch(boolean isStartMatch) {
+        this.isStartMatch = isStartMatch;
+    }
+
+    /**
+     * Return lastReadBytes.
+     * @return lastReadBytes
+     */
+    public int getLastReadBytes() {
+        return lastReadBytes;
+    }
+
+    /**
+     * Set lastReadBytes.
+     * @param lastReadBytes the bytes for last decoding incomplete record
+     */
+    public void setLastReadBytes(int lastReadBytes) {
+        this.lastReadBytes = lastReadBytes;
+    }
+}

+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed 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.onosproject.ovsdb.rfc.jsonrpc;
+
+import static com.google.common.base.MoreObjects.toStringHelper;
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import java.util.List;
+import java.util.Objects;
+
+import com.google.common.collect.Lists;
+
+/**
+ * Json Rpc Request information that include id,method,params.
+ */
+public class JsonRpcRequest {
+
+    private final String id;
+    private final String method;
+    private final List<Object> params;
+
+    /**
+     * JsonRpcRequest Constructor.
+     * @param id the id node of request information
+     * @param method the method node of request information
+     */
+    public JsonRpcRequest(String id, String method) {
+        checkNotNull(id, "id cannot be null");
+        checkNotNull(method, "method cannot be null");
+        this.id = id;
+        this.method = method;
+        this.params = Lists.newArrayList();
+    }
+
+    /**
+     * JsonRpcRequest Constructor.
+     * @param id the id node of request information
+     * @param method the method node of request information
+     * @param params the params node of request information
+     */
+    public JsonRpcRequest(String id, String method, List<Object> params) {
+        checkNotNull(id, "id cannot be null");
+        checkNotNull(method, "method cannot be null");
+        checkNotNull(params, "params cannot be null");
+        this.id = id;
+        this.method = method;
+        this.params = params;
+    }
+
+    /**
+     * Returns id.
+     * @return id
+     */
+    public String getId() {
+        return id;
+    }
+
+    /**
+     * Returns method.
+     * @return method
+     */
+    public String getMethod() {
+        return method;
+    }
+
+    /**
+     * Returns params.
+     * @return params
+     */
+    public List<Object> getParams() {
+        return params;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id, method, params);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj instanceof JsonRpcRequest) {
+            final JsonRpcRequest other = (JsonRpcRequest) obj;
+            return Objects.equals(this.id, other.id)
+                    && Objects.equals(this.method, other.method)
+                    && Objects.equals(this.params, other.params);
+        }
+        return false;
+    }
+
+    @Override
+    public String toString() {
+        return toStringHelper(this).add("id", id).add("method", method)
+                .add("params", params).toString();
+    }
+}

+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed 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.onosproject.ovsdb.rfc.jsonrpc;
+
+import static com.google.common.base.MoreObjects.toStringHelper;
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import java.util.List;
+import java.util.Objects;
+
+import com.google.common.collect.Lists;
+
+/**
+ * Json Rpc Response information that include id,error,result.
+ */
+public class JsonRpcResponse {
+
+    private final String id;
+    private final String error;
+    private final List<Object> result;
+
+    /**
+     * JsonRpcResponse Constructor.
+     * @param id the id node of response information
+     */
+    public JsonRpcResponse(String id) {
+        checkNotNull(id, "id cannot be null");
+        this.id = id;
+        this.error = null;
+        this.result = Lists.newArrayList();
+    }
+
+    /**
+     * JsonRpcResponse Constructor.
+     * @param id the id node of response information
+     * @param error the error node of response information
+     */
+    public JsonRpcResponse(String id, String error) {
+        checkNotNull(id, "id cannot be null");
+        checkNotNull(error, "error cannot be null");
+        this.id = id;
+        this.error = error;
+        this.result = Lists.newArrayList();
+    }
+
+    /**
+     * JsonRpcResponse Constructor.
+     * @param id the id node of response information
+     * @param error the error node of response information
+     * @param result the result node of response information
+     */
+    public JsonRpcResponse(String id, String error, List<Object> result) {
+        checkNotNull(id, "id cannot be null");
+        checkNotNull(error, "error cannot be null");
+        checkNotNull(result, "result cannot be null");
+        this.id = id;
+        this.error = error;
+        this.result = result;
+    }
+
+    /**
+     * Returns id.
+     * @return id
+     */
+    public String getId() {
+        return id;
+    }
+
+    /**
+     * Returns error.
+     * @return error
+     */
+    public String getError() {
+        return error;
+    }
+
+    /**
+     * Returns result.
+     * @return result
+     */
+    public List<Object> getResult() {
+        return result;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id, error, result);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj instanceof JsonRpcResponse) {
+            final JsonRpcResponse other = (JsonRpcResponse) obj;
+            return Objects.equals(this.id, other.id)
+                    && Objects.equals(this.error, other.error)
+                    && Objects.equals(this.result, other.result);
+        }
+        return false;
+    }
+
+    @Override
+    public String toString() {
+        return toStringHelper(this).add("id", id).add("error", error)
+                .add("result", result).toString();
+    }
+}

+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed 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.onosproject.ovsdb.rfc.jsonrpc;
+
+import java.util.List;
+
+import org.onosproject.ovsdb.rfc.operations.Operation;
+import org.onosproject.ovsdb.rfc.schema.DatabaseSchema;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.google.common.util.concurrent.ListenableFuture;
+
+/**
+ * The following interface describe the RPC7047's methods that are supported.
+ */
+public interface OvsdbRPC {
+
+    /**
+     * This operation retrieves a database-schema that describes hosted database
+     * db-name.
+     * @param dbnames database name
+     * @return ListenableFuture of JsonNode
+     */
+    ListenableFuture<JsonNode> getSchema(List<String> dbnames);
+
+    /**
+     * The "echo" method can be used by both clients and servers to verify the
+     * liveness of a database connection.
+     * @return return info
+     */
+    ListenableFuture<List<String>> echo();
+
+    /**
+     * The "monitor" request enables a client to replicate tables or subsets of
+     * tables within an OVSDB database by requesting notifications of changes to
+     * those tables and by receiving the complete initial state of a table or a
+     * subset of a table.
+     * @param dbSchema databse schema
+     * @param monitorId a id for monitor
+     * @return ListenableFuture of JsonNode
+     */
+    ListenableFuture<JsonNode> monitor(DatabaseSchema dbSchema, String monitorId);
+
+    /**
+     * This operation retrieves an array whose elements are the names of the
+     * databases that can be accessed over this management protocol connection.
+     * @return database names
+     */
+    ListenableFuture<List<String>> listDbs();
+
+    /**
+     * This RPC method causes the database server to execute a series of
+     * operations in the specified order on a given database.
+     * @param dbSchema database schema
+     * @param operations the operations to execute
+     * @return result the transact result
+     */
+    ListenableFuture<List<JsonNode>> transact(DatabaseSchema dbSchema,
+                                              List<Operation> operations);
+
+}

+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed 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.onosproject.ovsdb.rfc.table;
+
+/**
+ * Ovsdb table name. Refer to RFC7047's Section 9.2.
+ */
+public enum OvsdbTable {
+    INTERFACE("Interface"), BRIDGE("Bridge"), CONTROLLER("Controller"),
+    PORT("Port"), OPENVSWITCH("Open_vSwitch"), FLWTABLE("Flow_Table"),
+    QOS("Qos"), QUEUE("Queue"), MIRROR("Mirror"), MANAGER("Manager"),
+    NETFLOW("NetFlow"), SSL("SSL"), SFLOW("sFlow"), IPFIX("IPFIX"),
+    FLOWSAMPLECOLLECTORSET("Flow_Sample_Collector_Set");
+
+    private final String tableName;
+
+    private OvsdbTable(String tableName) {
+        this.tableName = tableName;
+    }
+
+    /**
+     * Returns the table name for OvsdbTable.
+     * @return the table name
+     */
+    public String tableName() {
+        return tableName;
+    }
+}

+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed 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.onosproject.ovsdb.rfc.table;
+
+import org.onosproject.ovsdb.rfc.notation.Row;
+import org.onosproject.ovsdb.rfc.schema.DatabaseSchema;
+
+/**
+ * Table generator.
+ */
+public final class TableGenerator {
+
+    /**
+     * Constructs a TableGenerator object. Utility classes should not have a
+     * public or default constructor, otherwise it will compile failed. This
+     * class should not be instantiated.
+     */
+    private TableGenerator() {
+    }
+
+    /**
+     * Create table.
+     * @param dbSchema DatabaseSchema entity
+     * @param tableName table name
+     * @return Object table entity
+     */
+    public static Object createTable(DatabaseSchema dbSchema,
+                                     OvsdbTable tableName) {
+        Row row = new Row();
+        return generateTable(dbSchema, row, tableName);
+    }
+
+    /**
+     * Get table from Row.
+     * @param dbSchema DatabaseSchema entity
+     * @param row Row entity
+     * @param tableName table name
+     * @return Object table entity
+     */
+    public static Object getTable(DatabaseSchema dbSchema, Row row,
+                                  OvsdbTable tableName) {
+        return generateTable(dbSchema, row, tableName);
+    }
+
+    /**
+     * Generate the table by table name.
+     * @param dbSchema DatabaseSchema entity
+     * @param row Row entity
+     * @param tableName table name
+     * @return Object Table entity
+     */
+    private static Object generateTable(DatabaseSchema dbSchema, Row row,
+                                        OvsdbTable tableName) {
+        switch (tableName) {
+        case INTERFACE:
+            return new Interface(dbSchema, row);
+        case BRIDGE:
+            return new Bridge(dbSchema, row);
+        case CONTROLLER:
+            return new Controller(dbSchema, row);
+        case OPENVSWITCH:
+            return new OpenVSwitch(dbSchema, row);
+        case PORT:
+            return new Port(dbSchema, row);
+        default:
+            return null;
+        }
+    }
+}

+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed 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.onosproject.ovsdb.rfc.table;
+
+/**
+ * The version number of tables and columns.
+ */
+public enum VersionNum {
+    VERSION100("1.0.0"), VERSION102("1.0.2"), VERSION103("1.0.3"),
+    VERSION104("1.0.4"), VERSION106("1.0.6"), VERSION110("1.1.0"),
+    VERSION130("1.3.0"), VERSION200("2.0.0"), VERSION300("3.0.0"),
+    VERSION330("3.3.0"), VERSION350("3.5.0"), VERSION400("4.0.0"),
+    VERSION510("5.1.0"), VERSION520("5.2.0"), VERSION600("6.0.0"),
+    VERSION610("6.1.0"), VERSION620("6.2.0"), VERSION630("6.3.0"),
+    VERSION640("6.4.0"), VERSION650("6.5.0"), VERSION660("6.6.0"),
+    VERSION670("6.7.0"), VERSION680("6.8.0"), VERSION690("6.9.0"),
+    VERSION6100("6.10.0"), VERSION6111("6.11.1"), VERSION710("7.1.0"),
+    VERSION720("7.2.0"), VERSION721("7.2.1"), VERSION730("7.3.0"),
+    VERSION740("7.4.0"), VERSION750("7.5.0"), VERSION770("7.7.0");
+
+    private final String versionNum;
+
+    private VersionNum(String versionNum) {
+        this.versionNum = versionNum;
+    }
+
+    /**
+     * Returns the version number for VersionNum.
+     * @return the version number
+     */
+    public String versionNum() {
+        return versionNum;
+    }
+}

+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed 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.onosproject.ovsdb.rfc.tableservice;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import org.onosproject.ovsdb.rfc.table.VersionNum;
+import org.onosproject.ovsdb.rfc.utils.VersionUtil;
+
+/**
+ * Column description.
+ */
+public class ColumnDescription {
+
+    // The column name
+    private final String name;
+    // The method name
+    private final String method;
+    // The initial version
+    private final String fromVersion;
+    // The end of the version
+    private final String untilVersion;
+
+    /**
+     * Constructs a MonitorRequest object.
+     * @param name column name
+     * @param method method name
+     */
+    public ColumnDescription(String name, String method) {
+        checkNotNull(name, "name cannot be null");
+        checkNotNull(method, "method cannot be null");
+        this.name = name;
+        this.method = method;
+        this.fromVersion = VersionUtil.DEFAULT_VERSION_STRING;
+        this.untilVersion = VersionUtil.DEFAULT_VERSION_STRING;
+    }
+
+    /**
+     * Constructs a MonitorRequest object.
+     * @param name column name
+     * @param method method name
+     * @param fromVersion the initial version
+     */
+    public ColumnDescription(String name, String method, VersionNum fromVersion) {
+        checkNotNull(name, "name cannot be null");
+        checkNotNull(method, "method cannot be null");
+        checkNotNull(fromVersion, "the initial version cannot be null");
+        this.name = name;
+        this.method = method;
+        this.fromVersion = fromVersion.versionNum();
+        this.untilVersion = VersionUtil.DEFAULT_VERSION_STRING;
+    }
+
+    /**
+     * Constructs a MonitorRequest object.
+     * @param name column name
+     * @param method method name
+     * @param fromVersion the initial version
+     * @param untilVersion the end of the version
+     */
+    public ColumnDescription(String name, String method, VersionNum fromVersion,
+                             VersionNum untilVersion) {
+        checkNotNull(name, "name cannot be null");
+        checkNotNull(method, "method cannot be null");
+        checkNotNull(fromVersion, "the initial version cannot be null");
+        checkNotNull(untilVersion, "the end of the version cannot be null");
+        this.name = name;
+        this.method = method;
+        this.fromVersion = fromVersion.versionNum();
+        this.untilVersion = untilVersion.versionNum();
+    }
+
+    /**
+     * Returns the column name.
+     * @return the column name
+     */
+    public String name() {
+        return name;
+    }
+
+    /**
+     * Returns the method name.
+     * @return the method name
+     */
+    public String method() {
+        return method;
+    }
+
+    /**
+     * Returns the initial version.
+     * @return the initial version
+     */
+    public String fromVersion() {
+        return fromVersion;
+    }
+
+    /**
+     * Returns the end of the version.
+     * @return the end of the version
+     */
+    public String untilVersion() {
+        return untilVersion;
+    }
+}

+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed 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.onosproject.ovsdb.rfc.tableservice;
+
+import org.onosproject.ovsdb.rfc.notation.Column;
+import org.onosproject.ovsdb.rfc.notation.UUID;
+
+/**
+ * Representation of conversion between Ovsdb table and Row.
+ */
+public interface OvsdbTableService {
+
+    /**
+     * Get Column from row.
+     * @param columndesc Column description
+     * @return Column
+     */
+    public Column getColumnHandler(ColumnDescription columndesc);
+
+    /**
+     * Get Data from row.
+     * @param columndesc Column description
+     * @return Object column data
+     */
+    public Object getDataHandler(ColumnDescription columndesc);
+
+    /**
+     * Set column data of row.
+     * @param columndesc Column description
+     * @param obj column data
+     */
+    public void setDataHandler(ColumnDescription columndesc, Object obj);
+
+    /**
+     * Returns the TableSchema from row.
+     * @return Object TableSchema
+     */
+    public Object getTbSchema();
+
+    /**
+     * Returns UUID which column name is _uuid.
+     * @return UUID
+     */
+    public UUID getUuid();
+
+    /**
+     * Returns UUID Column which column name is _uuid.
+     * @return UUID Column
+     */
+    public Column getUuidColumn();
+
+    /**
+     * Returns UUID which column name is _version.
+     * @return UUID
+     */
+    public UUID getVersion();
+
+    /**
+     * Returns UUID Column which column name is _version.
+     * @return UUID Column
+     */
+    public Column getVersionColumn();
+}

+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed 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.onosproject.ovsdb.rfc.tableservice;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import org.onosproject.ovsdb.rfc.table.OvsdbTable;
+import org.onosproject.ovsdb.rfc.table.VersionNum;
+import org.onosproject.ovsdb.rfc.utils.VersionUtil;
+
+/**
+ * Table description.
+ */
+public class TableDescription {
+
+    // The table name
+    private final String name;
+    // The database name
+    private final String database = "Open_vSwitch";
+    // The initial version
+    private final String fromVersion;
+    // The end of the version
+    private final String untilVersion;
+
+    /**
+     * Constructs a MonitorRequest object.
+     * @param table OvsdbTable entity
+     */
+    public TableDescription(OvsdbTable table) {
+        checkNotNull(table, "table cannot be null");
+        this.name = table.tableName();
+        this.fromVersion = VersionUtil.DEFAULT_VERSION_STRING;
+        this.untilVersion = VersionUtil.DEFAULT_VERSION_STRING;
+    }
+
+    /**
+     * Constructs a MonitorRequest object.
+     * @param table OvsdbTable entity
+     * @param fromVersion the initial version
+     */
+    public TableDescription(OvsdbTable table, VersionNum fromVersion) {
+        checkNotNull(table, "table cannot be null");
+        checkNotNull(fromVersion, "the initial version cannot be null");
+        this.name = table.tableName();
+        this.fromVersion = fromVersion.versionNum();
+        this.untilVersion = VersionUtil.DEFAULT_VERSION_STRING;
+    }
+
+    /**
+     * Constructs a MonitorRequest object.
+     * @param table OvsdbTable entity
+     * @param fromVersion the initial version
+     * @param untilVersion the end of the version
+     */
+    public TableDescription(OvsdbTable table, VersionNum fromVersion, VersionNum untilVersion) {
+        checkNotNull(table, "table cannot be null");
+        checkNotNull(fromVersion, "the initial version cannot be null");
+        checkNotNull(untilVersion, "the end of the version cannot be null");
+        this.name = table.tableName();
+        this.fromVersion = fromVersion.versionNum();
+        this.untilVersion = untilVersion.versionNum();
+    }
+
+    /**
+     * Returns the column name.
+     * @return the column name
+     */
+    public String name() {
+        return name;
+    }
+
+    /**
+     * Returns the database name.
+     * @return the database name
+     */
+    public String database() {
+        return database;
+    }
+
+    /**
+     * Returns the initial version.
+     * @return the initial version
+     */
+    public String fromVersion() {
+        return fromVersion;
+    }
+
+    /**
+     * Returns the end of the version.
+     * @return the end of the version
+     */
+    public String untilVersion() {
+        return untilVersion;
+    }
+}

+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed 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.onosproject.ovsdb.rfc.utils;
+
+import org.onosproject.ovsdb.rfc.notation.Condition;
+import org.onosproject.ovsdb.rfc.notation.Condition.Function;
+
+/**
+ * Condition utility class.
+ */
+public final class ConditionUtil {
+
+    /**
+     * Constructs a ConditionUtil object. Utility classes should not have a
+     * public or default constructor, otherwise IDE will compile unsuccessfully. This
+     * class should not be instantiated.
+     */
+    private ConditionUtil() {
+    }
+
+    /**
+     * Returns a Condition that means Function.EQUALS .
+     * @param columnName column name
+     * @param data column value
+     * @return Condition
+     */
+    public static Condition equals(String columnName, Object data) {
+        Object value = TransValueUtil.getFormatData(data);
+        return new Condition(columnName, Function.EQUALS, value);
+    }
+
+    /**
+     * Returns a Condition that means Function.NOT_EQUALS .
+     * @param columnName column name
+     * @param data column value
+     * @return Condition
+     */
+    public static Condition unEquals(String columnName, Object data) {
+        Object value = TransValueUtil.getFormatData(data);
+        return new Condition(columnName, Function.NOT_EQUALS, value);
+    }
+
+    /**
+     * Returns a Condition that means Function.GREATER_THAN .
+     * @param columnName column name
+     * @param data column value
+     * @return Condition
+     */
+    public static Condition greaterThan(String columnName, Object data) {
+        Object value = TransValueUtil.getFormatData(data);
+        return new Condition(columnName, Function.GREATER_THAN, value);
+    }
+
+    /**
+     * Returns a Condition that means Function.GREATER_THAN_OR_EQUALS .
+     * @param columnName column name
+     * @param data column value
+     * @return Condition
+     */
+    public static Condition greaterThanOrEquals(String columnName, Object data) {
+        Object value = TransValueUtil.getFormatData(data);
+        return new Condition(columnName, Function.GREATER_THAN_OR_EQUALS, value);
+    }
+
+    /**
+     * Returns a Condition that means Function.LESS_THAN .
+     * @param columnName column name
+     * @param data column value
+     * @return Condition
+     */
+    public static Condition lesserThan(String columnName, Object data) {
+        Object value = TransValueUtil.getFormatData(data);
+        return new Condition(columnName, Function.LESS_THAN, value);
+    }
+
+    /**
+     * Returns a Condition that means Function.LESS_THAN_OR_EQUALS .
+     * @param columnName column name
+     * @param data column value
+     * @return Condition
+     */
+    public static Condition lesserThanOrEquals(String columnName, Object data) {
+        Object value = TransValueUtil.getFormatData(data);
+        return new Condition(columnName, Function.LESS_THAN_OR_EQUALS, value);
+    }
+
+    /**
+     * Returns a Condition that means Function.INCLUDES .
+     * @param columnName column name
+     * @param data column value
+     * @return Condition
+     */
+    public static Condition includes(String columnName, Object data) {
+        Object value = TransValueUtil.getFormatData(data);
+        return new Condition(columnName, Function.INCLUDES, value);
+    }
+
+    /**
+     * Returns a Condition that means Function.EXCLUDES .
+     * @param columnName column name
+     * @param data column value
+     * @return Condition
+     */
+    public static Condition excludes(String columnName, Object data) {
+        Object value = TransValueUtil.getFormatData(data);
+        return new Condition(columnName, Function.EXCLUDES, value);
+    }
+
+}

+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed 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.onosproject.ovsdb.rfc.utils;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufInputStream;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Stack;
+
+import org.onosproject.ovsdb.rfc.error.UnsupportedEncodingException;
+import org.onosproject.ovsdb.rfc.jsonrpc.JsonReadContext;
+
+import com.fasterxml.jackson.core.JsonEncoding;
+import com.fasterxml.jackson.core.JsonParseException;
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.io.IOContext;
+import com.fasterxml.jackson.core.json.ByteSourceJsonBootstrapper;
+import com.fasterxml.jackson.core.util.BufferRecycler;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.MappingJsonFactory;
+
+/**
+ * Decoder utility class.
+ */
+public final class JsonRpcReaderUtil {
+
+    /**
+     * Constructs a JsonRpcReaderUtil object. Utility classes should not have a
+     * public or default constructor, otherwise IDE will compile unsuccessfully.
+     * This class should not be instantiated.
+     */
+    private JsonRpcReaderUtil() {
+    }
+
+    /**
+     * Decode the bytes to Json object.
+     * @param in input of bytes
+     * @param out ouput of Json object list
+     * @param jrContext context for the last decoding process
+     * @throws IOException IOException
+     * @throws JsonParseException JsonParseException
+     */
+    public static void readToJsonNode(ByteBuf in, List<Object> out,
+                                      JsonReadContext jrContext)
+            throws JsonParseException, IOException {
+        int lastReadBytes = jrContext.getLastReadBytes();
+        if (lastReadBytes == 0) {
+            if (in.readableBytes() < 4) {
+                return;
+            }
+            checkEncoding(in);
+        }
+
+        int i = lastReadBytes + in.readerIndex();
+        Stack<Byte> bufStack = jrContext.getBufStack();
+        for (; i < in.writerIndex(); i++) {
+            byte b = in.getByte(i);
+            switch (b) {
+            case '{':
+                if (!isDoubleQuote(bufStack)) {
+                    bufStack.push(b);
+                    jrContext.setStartMatch(true);
+                }
+                break;
+            case '}':
+                if (!isDoubleQuote(bufStack)) {
+                    bufStack.pop();
+                }
+                break;
+            case '"':
+                if (in.getByte(i - 1) != '\\') {
+                    if (!bufStack.isEmpty() && bufStack.peek() != '"') {
+                        bufStack.push(b);
+                    } else {
+                        bufStack.pop();
+                    }
+                }
+                break;
+            default:
+                break;
+            }
+
+            if (jrContext.isStartMatch() && bufStack.isEmpty()) {
+                ByteBuf buf = in.readSlice(i - in.readerIndex() + 1);
+                JsonParser jf = new MappingJsonFactory()
+                        .createParser(new ByteBufInputStream(buf));
+                JsonNode jsonNode = jf.readValueAsTree();
+                out.add(jsonNode);
+                lastReadBytes = 0;
+                jrContext.setLastReadBytes(lastReadBytes);
+                break;
+            }
+        }
+
+        if (i >= in.writerIndex()) {
+            lastReadBytes = in.readableBytes();
+            jrContext.setLastReadBytes(lastReadBytes);
+        }
+    }
+
+    /**
+     * Filter the invalid characters before decoding.
+     * @param in input of bytes
+     * @param lastReadBytes the bytes for last decoding incomplete record
+     */
+    private static void fliterCharaters(ByteBuf in) {
+        while (in.isReadable()) {
+            int ch = in.getByte(in.readerIndex());
+            if ((ch != ' ') && (ch != '\n') && (ch != '\t') && (ch != '\r')) {
+                break;
+            } else {
+                in.readByte();
+            }
+        }
+    }
+
+    /**
+     * Check whether the peek of the stack element is double quote.
+     * @param jrContext context for the last decoding process
+     * @return boolean
+     */
+    private static boolean isDoubleQuote(Stack<Byte> bufStack) {
+        if (!bufStack.isEmpty() && bufStack.peek() == '"') {
+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * Check whether the encoding is valid.
+     * @param in input of bytes
+     * @throws IOException this is an IO exception
+     * @throws UnsupportedEncodingException this is an unsupported encode
+     *             exception
+     */
+    private static void checkEncoding(ByteBuf in) throws IOException {
+        int inputStart = 0;
+        int inputLength = 4;
+        fliterCharaters(in);
+        byte[] buff = new byte[4];
+        in.getBytes(in.readerIndex(), buff);
+        ByteSourceJsonBootstrapper strapper = new ByteSourceJsonBootstrapper(
+                                                                             new IOContext(
+                                                                                           new BufferRecycler(),
+                                                                                           null,
+                                                                                           false),
+                                                                             buff,
+                                                                             inputStart,
+                                                                             inputLength);
+        JsonEncoding jsonEncoding = strapper.detectEncoding();
+        if (!JsonEncoding.UTF8.equals(jsonEncoding)) {
+            throw new UnsupportedEncodingException(
+                                                   "Only UTF-8 encoding is supported.");
+        }
+    }
+
+}

+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed 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.onosproject.ovsdb.rfc.utils;
+
+import java.util.List;
+
+import org.onosproject.ovsdb.rfc.jsonrpc.JsonRpcRequest;
+import org.onosproject.ovsdb.rfc.operations.Operation;
+import org.onosproject.ovsdb.rfc.schema.DatabaseSchema;
+
+/**
+ * RPC Methods request utility class. Refer to RFC7047's Section 4.1.
+ */
+public final class JsonRpcWriterUtil {
+
+    /**
+     * Constructs a JsonRpcWriterUtil object. Utility classes should not have a
+     * public or default constructor, otherwise IDE will compile unsuccessfully.
+     * This class should not be instantiated.
+     */
+    private JsonRpcWriterUtil() {
+    }
+
+    /**
+     * Returns string of RPC request.
+     * @param uuid id of request object
+     * @param methodName method of request object
+     * @param params params of request object
+     * @return RPC Request String
+     */
+    private static String getRequestStr(String uuid, String methodName,
+                                        List params) {
+        JsonRpcRequest request;
+        if (params != null) {
+            request = new JsonRpcRequest(uuid, methodName, params);
+        } else {
+            request = new JsonRpcRequest(uuid, methodName);
+        }
+        String str = ObjectMapperUtil.convertToString(request);
+        return str;
+    }
+
+    /**
+     * Returns string of get_schema request.
+     * @param uuid id of get_schema request
+     * @param dbnames params of get_schema request
+     * @return get_schema Request String
+     */
+    public static String getSchemaStr(String uuid, List<String> dbnames) {
+        String methodName = "get_schema";
+        return getRequestStr(uuid, methodName, dbnames);
+    }
+
+    /**
+     * Returns string of echo request.
+     * @param uuid id of echo request
+     * @return echo Request String
+     */
+    public static String echoStr(String uuid) {
+        String methodName = "echo";
+        return getRequestStr(uuid, methodName, null);
+    }
+
+    /**
+     * Returns string of monitor request.
+     * @param uuid id of monitor request
+     * @param monotorId json-value in params of monitor request
+     * @param dbSchema DatabaseSchema entity
+     * @return monitor Request String
+     */
+    public static String monitorStr(String uuid, String monotorId,
+                                    DatabaseSchema dbSchema) {
+        String methodName = "monitor";
+        return getRequestStr(uuid, methodName,
+                             ParamUtil.getMonitorParams(monotorId, dbSchema));
+    }
+
+    /**
+     * Returns string of list_dbs request.
+     * @param uuid id of list_dbs request
+     * @return list_dbs Request String
+     */
+    public static String listDbsStr(String uuid) {
+        String methodName = "list_dbs";
+        return getRequestStr(uuid, methodName, null);
+    }
+
+    /**
+     * Returns string of transact request.
+     * @param uuid id of transact request
+     * @param dbSchema DatabaseSchema entity
+     * @param operations operation* in params of transact request
+     * @return transact Request String
+     */
+    public static String transactStr(String uuid, DatabaseSchema dbSchema,
+                                     List<Operation> operations) {
+        String methodName = "transact";
+        return getRequestStr(uuid, methodName,
+                             ParamUtil.getTransactParams(dbSchema, operations));
+    }
+}

+package org.onosproject.ovsdb.rfc.utils;
+
+import org.onosproject.ovsdb.rfc.notation.Mutation;
+import org.onosproject.ovsdb.rfc.notation.Mutation.Mutator;
+
+public final class MutationUtil {
+
+    /**
+     * Constructs a MutationUtil object. Utility classes should not have a
+     * public or default constructor, otherwise IDE will compile unsuccessfully. This
+     * class should not be instantiated.
+     */
+    private MutationUtil() {
+    }
+
+    /**
+     * Returns a Mutation that means += .
+     * @param columnName column name
+     * @param data column value
+     * @return Mutation
+     */
+    public static Mutation sum(String columnName, Object data) {
+        Object value = TransValueUtil.getFormatData(data);
+        return new Mutation(columnName, Mutator.SUM, value);
+    }
+
+    /**
+     * Returns a Mutation that means -= .
+     * @param columnName column name
+     * @param data column value
+     * @return Mutation
+     */
+    public static Mutation difference(String columnName, Object data) {
+        Object value = TransValueUtil.getFormatData(data);
+        return new Mutation(columnName, Mutator.DIFFERENCE, value);
+    }
+
+    /**
+     * Returns a Mutation that means *= .
+     * @param columnName column name
+     * @param data column value
+     * @return Mutation
+     */
+    public static Mutation product(String columnName, Object data) {
+        Object value = TransValueUtil.getFormatData(data);
+        return new Mutation(columnName, Mutator.PRODUCT, value);
+    }
+
+    /**
+     * Returns a Mutation that means /= .
+     * @param columnName column name
+     * @param data column value
+     * @return Mutation
+     */
+    public static Mutation quotient(String columnName, Object data) {
+        Object value = TransValueUtil.getFormatData(data);
+        return new Mutation(columnName, Mutator.QUOTIENT, value);
+    }
+
+    /**
+     * Returns a Mutation that means %= .
+     * @param columnName column name
+     * @param data column value
+     * @return Mutation
+     */
+    public static Mutation remainder(String columnName, Object data) {
+        Object value = TransValueUtil.getFormatData(data);
+        return new Mutation(columnName, Mutator.REMAINDER, value);
+    }
+
+    /**
+     * Returns a Mutation that means insert .
+     * @param columnName column name
+     * @param data column value
+     * @return Mutation
+     */
+    public static Mutation insert(String columnName, Object data) {
+        Object value = TransValueUtil.getFormatData(data);
+        return new Mutation(columnName, Mutator.INSERT, value);
+    }
+
+    /**
+     * Returns a Mutation that means delete .
+     * @param columnName column name
+     * @param data column value
+     * @return Mutation
+     */
+    public static Mutation delete(String columnName, Object data) {
+        Object value = TransValueUtil.getFormatData(data);
+        return new Mutation(columnName, Mutator.DELETE, value);
+    }
+}

+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed 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.onosproject.ovsdb.rfc.utils;
+
+import java.util.List;
+import java.util.Set;
+
+import org.onosproject.ovsdb.rfc.message.MonitorRequest;
+import org.onosproject.ovsdb.rfc.message.MonitorSelect;
+import org.onosproject.ovsdb.rfc.operations.Operation;
+import org.onosproject.ovsdb.rfc.schema.DatabaseSchema;
+import org.onosproject.ovsdb.rfc.schema.TableSchema;
+
+import com.google.common.base.Function;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Lists;
+import com.google.common.collect.Maps;
+
+/**
+ * Params utility class. Params of the request object, refer to RFC7047's Section
+ * 4.1.
+ */
+public final class ParamUtil {
+
+    /**
+     * Constructs a ParamUtil object. Utility classes should not have a
+     * public or default constructor, otherwise IDE will compile unsuccessfully. This
+     * class should not be instantiated.
+     */
+    private ParamUtil() {
+    }
+
+    /**
+     * Returns MonitorRequest, refer to RFC7047's Section 4.1.5.
+     * @param tableSchema entity
+     * @return MonitorRequest
+     */
+    private static MonitorRequest getAllColumnsMonitorRequest(TableSchema tableSchema) {
+        String tableName = tableSchema.name();
+        Set<String> columns = tableSchema.getColumnNames();
+        MonitorSelect select = new MonitorSelect(true, true, true, true);
+        MonitorRequest monitorRequest = new MonitorRequest(tableName, columns,
+                                                           select);
+        return monitorRequest;
+    }
+
+    /**
+     * Returns params of monitor method, refer to RFC7047's Section 4.1.5.
+     * @param monotorId json-value, refer to RFC7047's Section 4.1.5.
+     * @param dbSchema DatabaseSchema entity
+     * @return List of Object, the params of monitor request
+     */
+    public static List<Object> getMonitorParams(String monotorId,
+                                                DatabaseSchema dbSchema) {
+        Set<String> tables = dbSchema.getTableNames();
+        List<MonitorRequest> monitorRequests = Lists.newArrayList();
+        for (String tableName : tables) {
+            TableSchema tableSchema = dbSchema.getTableSchema(tableName);
+            monitorRequests.add(getAllColumnsMonitorRequest(tableSchema));
+        }
+        ImmutableMap<String, MonitorRequest> reqMap = Maps
+                .uniqueIndex(monitorRequests,
+                             new Function<MonitorRequest, String>() {
+                                 @Override
+                                 public String apply(MonitorRequest input) {
+                                     return input.getTableName();
+                                 }
+                             });
+        return Lists.<Object>newArrayList(dbSchema.name(), monotorId,
+                                           reqMap);
+    }
+
+    /**
+     * Returns params of transact method, refer to RFC7047's Section 4.1.3.
+     * @param dbSchema DatabaseSchema entity
+     * @param operations operation*, refer to RFC7047's Section 4.1.3.
+     * @return List of Object, the params of transact request
+     */
+    public static List<Object> getTransactParams(DatabaseSchema dbSchema,
+                                                 List<Operation> operations) {
+        List<Object> lists = Lists.newArrayList((Object) dbSchema.name());
+        lists.addAll(operations);
+        return lists;
+    }
+}

+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed 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.onosproject.ovsdb.rfc.utils;
+
+import io.netty.handler.codec.string.StringEncoder;
+import io.netty.util.CharsetUtil;
+
+/**
+ * StringEncoder utility class.Only UTF-8 encoding is supported refer to
+ * RFC7047's Section 3.1.
+ */
+public final class StringEncoderUtil {
+
+    /**
+     * Constructs a StringEncoderUtil object. Utility classes should not have a
+     * public or default constructor, otherwise IDE will compile unsuccessfully. This
+     * class should not be instantiated.
+     */
+    private StringEncoderUtil() {
+    }
+
+    /**
+     * Returns StringEncoder of UTF_8 .
+     * @return StringEncoder
+     */
+    public static StringEncoder getEncoder() {
+        return new StringEncoder(CharsetUtil.UTF_8);
+    }
+}

+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed 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.onosproject.ovsdb.rfc.utils;
+
+/**
+ * Version utility class.
+ */
+public final class VersionUtil {
+
+    /**
+     * Constructs a VersionUtil object. Utility classes should not have a public
+     * or default constructor, otherwise IDE will compile unsuccessfully. This
+     * class should not be instantiated.
+     */
+    private VersionUtil() {
+    }
+
+    public static final String DEFAULT_VERSION_STRING = "0.0.0";
+    private static final String FORMAT = "(\\d+)\\.(\\d+)\\.(\\d+)";
+
+    /**
+     * Match version by the format.
+     * @param version the version String
+     * @throws IllegalArgumentException this is an illegal argument exception
+     */
+    public static void versionMatch(String version) {
+        if (!version.matches(FORMAT)) {
+            throw new IllegalArgumentException("<" + version
+                    + "> does not match format " + FORMAT);
+        }
+    }
+
+    /**
+     * Compare fromVersion and toVersion.
+     * @param fromVersion the initial version
+     * @param toVersion the end of the version
+     * @return a long number
+     */
+    public static long versionCompare(String fromVersion, String toVersion) {
+        Long fromNum = Long.parseLong(fromVersion.replace(".", ""));
+        Long toNum = Long.parseLong(toVersion.replace(".", ""));
+        return (fromNum - toNum);
+    }
+}