Add LispMessageEncoder and LispMessageDecoder with unit tests

Change-Id: If73a41687a9c2400de23bbde6179a63ac7f75d15

 COMPILE_DEPS = [
     '//lib:CORE_DEPS',
-    '//protocols/lisp/api:onos-protocols-lisp-api'
+    '//protocols/lisp/api:onos-protocols-lisp-api',
+    '//protocols/lisp/msg:onos-protocols-lisp-msg',
+    '//lib:netty-buffer',
+    '//lib:netty-codec',
+    '//lib:netty-transport'
 ]
 
 TEST_DEPS = [

@@ -41,6 +41,11 @@
         </dependency>
         <dependency>
             <groupId>org.onosproject</groupId>
+            <artifactId>onos-lisp-msg</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.onosproject</groupId>
             <artifactId>onos-api</artifactId>
             <classifier>tests</classifier>
             <scope>test</scope>

@@ -15,10 +15,26 @@
  */
 package org.onosproject.lisp.ctl;
 
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.ByteToMessageDecoder;
+import org.onosproject.lisp.msg.protocols.LispMessage;
+import org.onosproject.lisp.msg.protocols.LispMessageReader;
+import org.onosproject.lisp.msg.protocols.LispMessageReaderFactory;
+
+import java.util.List;
+
 /**
- * Remove me.
+ * Decode a LISP message from a ByteBuffer, for use in a netty pipeline.
  */
-@Deprecated
-public abstract class PlaceHolder {
+public class LispMessageDecoder extends ByteToMessageDecoder {
+
+    @Override
+    protected void decode(ChannelHandlerContext ctx, ByteBuf byteBuf,
+                          List<Object> list) throws Exception {
 
+        LispMessageReader reader = LispMessageReaderFactory.getReader(byteBuf);
+        LispMessage message = (LispMessage) reader.readFrom(byteBuf);
+        list.add(message);
+    }
 }

+/*
+ * Copyright 2016-present 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.lisp.ctl;
+
+
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.MessageToByteEncoder;
+import org.onosproject.lisp.msg.protocols.LispMessage;
+
+import java.util.List;
+
+/**
+ * Encode a LISP message for output into a ByteBuffer,
+ * for use in a netty pipeline.
+ */
+public class LispMessageEncoder extends MessageToByteEncoder {
+
+    @Override
+    protected void encode(ChannelHandlerContext ctx, Object msg, ByteBuf out) throws Exception {
+        if (!(msg instanceof List)) {
+            ((LispMessage) msg).writeTo(out);
+            return;
+        }
+
+        List<LispMessage> msgList = (List<LispMessage>) msg;
+
+        for (LispMessage message : msgList) {
+            if (message != null) {
+                message.writeTo(out);
+            }
+        }
+    }
+}

+/*
+ * Copyright 2016-present 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.lisp.ctl;
+
+import io.netty.buffer.ByteBufAllocator;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelConfig;
+import io.netty.channel.ChannelFuture;
+import io.netty.channel.ChannelPipeline;
+import io.netty.channel.ChannelPromise;
+import io.netty.channel.ChannelProgressivePromise;
+import io.netty.channel.ChannelMetadata;
+import io.netty.channel.EventLoop;
+import io.netty.util.Attribute;
+import io.netty.util.AttributeKey;
+
+import java.net.SocketAddress;
+
+/**
+ * Adapter for testing against a netty channel.
+ */
+public class ChannelAdapter implements Channel {
+    @Override
+    public EventLoop eventLoop() {
+        return null;
+    }
+
+    @Override
+    public Channel parent() {
+        return null;
+    }
+
+    @Override
+    public ChannelConfig config() {
+        return null;
+    }
+
+    @Override
+    public boolean isOpen() {
+        return false;
+    }
+
+    @Override
+    public boolean isRegistered() {
+        return false;
+    }
+
+    @Override
+    public boolean isActive() {
+        return false;
+    }
+
+    @Override
+    public ChannelMetadata metadata() {
+        return null;
+    }
+
+    @Override
+    public SocketAddress localAddress() {
+        return null;
+    }
+
+    @Override
+    public SocketAddress remoteAddress() {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture closeFuture() {
+        return null;
+    }
+
+    @Override
+    public boolean isWritable() {
+        return false;
+    }
+
+    @Override
+    public Unsafe unsafe() {
+        return null;
+    }
+
+    @Override
+    public ChannelPipeline pipeline() {
+        return null;
+    }
+
+    @Override
+    public ByteBufAllocator alloc() {
+        return null;
+    }
+
+    @Override
+    public ChannelPromise newPromise() {
+        return null;
+    }
+
+    @Override
+    public ChannelProgressivePromise newProgressivePromise() {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture newSucceededFuture() {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture newFailedFuture(Throwable cause) {
+        return null;
+    }
+
+    @Override
+    public ChannelPromise voidPromise() {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture bind(SocketAddress localAddress) {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture connect(SocketAddress remoteAddress) {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture connect(SocketAddress remoteAddress, SocketAddress localAddress) {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture disconnect() {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture close() {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture deregister() {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture bind(SocketAddress localAddress, ChannelPromise promise) {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture connect(SocketAddress remoteAddress, ChannelPromise promise) {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture connect(SocketAddress remoteAddress, SocketAddress localAddress, ChannelPromise promise) {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture disconnect(ChannelPromise promise) {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture close(ChannelPromise promise) {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture deregister(ChannelPromise promise) {
+        return null;
+    }
+
+    @Override
+    public Channel read() {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture write(Object msg) {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture write(Object msg, ChannelPromise promise) {
+        return null;
+    }
+
+    @Override
+    public Channel flush() {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture writeAndFlush(Object msg, ChannelPromise promise) {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture writeAndFlush(Object msg) {
+        return null;
+    }
+
+    @Override
+    public <T> Attribute<T> attr(AttributeKey<T> attributeKey) {
+        return null;
+    }
+
+    @Override
+    public int compareTo(Channel o) {
+        return 0;
+    }
+}

+/*
+ * Copyright 2016-present 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.lisp.ctl;
+
+
+import io.netty.buffer.ByteBufAllocator;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelFuture;
+import io.netty.channel.ChannelHandler;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelPromise;
+import io.netty.channel.ChannelPipeline;
+import io.netty.channel.ChannelProgressivePromise;
+import io.netty.util.Attribute;
+import io.netty.util.AttributeKey;
+import io.netty.util.concurrent.EventExecutor;
+
+import java.net.SocketAddress;
+
+/**
+ * Adapter for testing against a netty channel handler context.
+ */
+public class ChannelHandlerContextAdapter implements ChannelHandlerContext {
+
+    @Override
+    public Channel channel() {
+        return null;
+    }
+
+    @Override
+    public EventExecutor executor() {
+        return null;
+    }
+
+    @Override
+    public String name() {
+        return null;
+    }
+
+    @Override
+    public ChannelHandler handler() {
+        return null;
+    }
+
+    @Override
+    public boolean isRemoved() {
+        return false;
+    }
+
+    @Override
+    public ChannelHandlerContext fireChannelRegistered() {
+        return null;
+    }
+
+    @Override
+    public ChannelHandlerContext fireChannelUnregistered() {
+        return null;
+    }
+
+    @Override
+    public ChannelHandlerContext fireChannelActive() {
+        return null;
+    }
+
+    @Override
+    public ChannelHandlerContext fireChannelInactive() {
+        return null;
+    }
+
+    @Override
+    public ChannelHandlerContext fireExceptionCaught(Throwable cause) {
+        return null;
+    }
+
+    @Override
+    public ChannelHandlerContext fireUserEventTriggered(Object evt) {
+        return null;
+    }
+
+    @Override
+    public ChannelHandlerContext fireChannelRead(Object msg) {
+        return null;
+    }
+
+    @Override
+    public ChannelHandlerContext fireChannelReadComplete() {
+        return null;
+    }
+
+    @Override
+    public ChannelHandlerContext fireChannelWritabilityChanged() {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture bind(SocketAddress localAddress) {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture connect(SocketAddress remoteAddress) {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture connect(SocketAddress remoteAddress, SocketAddress localAddress) {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture disconnect() {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture close() {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture deregister() {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture bind(SocketAddress localAddress, ChannelPromise promise) {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture connect(SocketAddress remoteAddress, ChannelPromise promise) {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture connect(SocketAddress remoteAddress, SocketAddress localAddress, ChannelPromise promise) {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture disconnect(ChannelPromise promise) {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture close(ChannelPromise promise) {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture deregister(ChannelPromise promise) {
+        return null;
+    }
+
+    @Override
+    public ChannelHandlerContext read() {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture write(Object msg) {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture write(Object msg, ChannelPromise promise) {
+        return null;
+    }
+
+    @Override
+    public ChannelHandlerContext flush() {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture writeAndFlush(Object msg, ChannelPromise promise) {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture writeAndFlush(Object msg) {
+        return null;
+    }
+
+    @Override
+    public ChannelPipeline pipeline() {
+        return null;
+    }
+
+    @Override
+    public ByteBufAllocator alloc() {
+        return null;
+    }
+
+    @Override
+    public ChannelPromise newPromise() {
+        return null;
+    }
+
+    @Override
+    public ChannelProgressivePromise newProgressivePromise() {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture newSucceededFuture() {
+        return null;
+    }
+
+    @Override
+    public ChannelFuture newFailedFuture(Throwable cause) {
+        return null;
+    }
+
+    @Override
+    public ChannelPromise voidPromise() {
+        return null;
+    }
+
+    @Override
+    public <T> Attribute<T> attr(AttributeKey<T> attributeKey) {
+        return null;
+    }
+}

+/*
+ * Copyright 2016-present 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.lisp.ctl;
+
+import com.google.common.collect.ImmutableList;
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import org.junit.Test;
+import org.onosproject.lisp.msg.protocols.LispType;
+
+import java.nio.charset.StandardCharsets;
+import java.util.List;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.notNullValue;
+
+/**
+ * Tests for LISP message encoder.
+ */
+public class LIspMessageEncoderTest {
+
+    static class MockLispMessage extends LispMessageAdapter {
+        LispType type;
+
+        public MockLispMessage(LispType type) {
+            super(type);
+            this.type = type;
+        }
+
+        @Override
+        public void writeTo(ByteBuf buffer) {
+            String message = "LISP message [" + type.toString() + "] ";
+            buffer.writeBytes(message.getBytes(StandardCharsets.UTF_8));
+        }
+    }
+
+    @Test
+    public void testEncodeOneEntry() throws Exception {
+        LispMessageEncoder encoder = new LispMessageEncoder();
+        MockLispMessage message = new MockLispMessage(LispType.LISP_MAP_REQUEST);
+        ByteBuf buff = Unpooled.buffer();
+        encoder.encode(null, message, buff);
+
+        assertThat(buff, notNullValue());
+
+        String expected = "LISP message [LISP_MAP_REQUEST] ";
+        String returned = new String(buff.array(), StandardCharsets.UTF_8).substring(0, expected.length());
+        assertThat(returned, is(expected));
+    }
+
+    @Test
+    public void testEncode() throws Exception {
+        LispMessageEncoder encoder = new LispMessageEncoder();
+        MockLispMessage request = new MockLispMessage(LispType.LISP_MAP_REQUEST);
+        MockLispMessage reply = new MockLispMessage(LispType.LISP_MAP_REPLY);
+        MockLispMessage register = new MockLispMessage(LispType.LISP_MAP_REGISTER);
+        MockLispMessage notify = new MockLispMessage(LispType.LISP_MAP_NOTIFY);
+
+        ByteBuf buff = Unpooled.buffer();
+        List<MockLispMessage> messages = ImmutableList.of(request, reply, register, notify);
+        encoder.encode(null, messages, buff);
+
+        assertThat(buff, notNullValue());
+
+        StringBuilder expBuilder = new StringBuilder();
+        expBuilder.append("LISP message [LISP_MAP_REQUEST] ");
+        expBuilder.append("LISP message [LISP_MAP_REPLY] ");
+        expBuilder.append("LISP message [LISP_MAP_REGISTER] ");
+        expBuilder.append("LISP message [LISP_MAP_NOTIFY] ");
+
+        String expected = expBuilder.toString();
+        String returned = new String(buff.array(), StandardCharsets.UTF_8).substring(0, expected.length());
+        assertThat(returned, is(expected));
+    }
+}

+/*
+ * Copyright 2016-present 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.lisp.ctl;
+
+import io.netty.buffer.ByteBuf;
+import org.onosproject.lisp.msg.protocols.LispMessage;
+import org.onosproject.lisp.msg.protocols.LispType;
+
+/**
+ * Adapter for testing against a LISP message.
+ */
+public class LispMessageAdapter implements LispMessage {
+    LispType type;
+
+    private LispMessageAdapter() {}
+
+    public LispMessageAdapter(LispType type) {
+        this.type = type;
+    }
+
+    @Override
+    public LispType getType() {
+        return type;
+    }
+
+    @Override
+    public void writeTo(ByteBuf byteBuf) {
+
+    }
+
+    @Override
+    public Builder createBuilder() {
+        return null;
+    }
+}

+/*
+ * Copyright 2016-present 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.lisp.ctl;
+
+import com.google.common.collect.Lists;
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import org.junit.Test;
+import org.onosproject.lisp.msg.protocols.LispMapNotify;
+import org.onosproject.lisp.msg.protocols.LispMapRegister;
+import org.onosproject.lisp.msg.protocols.LispMapReply;
+import org.onosproject.lisp.msg.protocols.LispMapRequest;
+
+import java.util.List;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.instanceOf;
+import static org.hamcrest.Matchers.is;
+
+/**
+ * Tests for LISP message decoder.
+ */
+public class LispMessageDecoderTest {
+
+    private static final int TYPE_SHIFT_BIT = 4;
+    private static final byte MAP_REQUEST = 1;
+    private static final byte MAP_REPLY = 2;
+    private static final byte MAP_REGISTER = 3;
+    private static final byte MAP_NOTIFY = 4;
+
+
+    private ByteBuf getLispMapRequestBuffer() {
+        ByteBuf buffer = Unpooled.buffer();
+
+        // specify message type
+        buffer.writeByte(MAP_REQUEST << TYPE_SHIFT_BIT);
+
+        // fill up message payload
+        // second byte denotes the number of RLOCs
+        byte[] messageData = {0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0};
+        byte[] eidData = {0x0, 0x1, 0x0, 0x0, 0x0, 0x0};
+        byte[] rlocData = {0x0, 0x1, 0x0, 0x0, 0x0, 0x0};
+        buffer.writeBytes(messageData);
+        buffer.writeBytes(eidData);
+        buffer.writeBytes(rlocData);
+        return buffer;
+    }
+
+    private ByteBuf getLispMapReplyBuffer() {
+        ByteBuf buffer = Unpooled.buffer();
+
+        // specify message type
+        buffer.writeByte(MAP_REPLY << TYPE_SHIFT_BIT);
+
+        // fill up message payload
+        byte[] messageData = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0};
+        buffer.writeBytes(messageData);
+        return buffer;
+    }
+
+    private ByteBuf getLispMapRegisterBuffer() {
+        ByteBuf buffer = Unpooled.buffer();
+
+        // specify message type
+        buffer.writeByte(MAP_REGISTER << TYPE_SHIFT_BIT);
+
+        // fill up message payload
+        byte[] messageData = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0};
+        byte[] keyId = {0x0, 0x1};
+
+        // assume that we have auth data which has 2 bytes size
+        byte[] authDataLength = {0x0, 0x2};
+        byte[] authData = {0x0, 0x0};
+
+        buffer.writeBytes(messageData);
+        buffer.writeBytes(keyId);
+        buffer.writeBytes(authDataLength);
+        buffer.writeBytes(authData);
+        return buffer;
+    }
+
+    private ByteBuf getLispMapNotifyBuffer() {
+        ByteBuf buffer = Unpooled.buffer();
+
+        // specify message type
+        buffer.writeByte(MAP_NOTIFY << TYPE_SHIFT_BIT);
+
+        // fill up message payload
+        byte[] messageData = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0};
+        byte[] keyId = {0x0, 0x1};
+
+        // assume that we have auth data which has 2 bytes size
+        byte[] authDataLength = {0x0, 0x2};
+        byte[] authData = {0x0, 0x0};
+
+        buffer.writeBytes(messageData);
+        buffer.writeBytes(keyId);
+        buffer.writeBytes(authDataLength);
+        buffer.writeBytes(authData);
+
+        return buffer;
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testDecodeNoChannel() throws Exception {
+        LispMessageDecoder decoder = new LispMessageDecoder();
+
+        List<Object> list = Lists.newArrayList();
+        decoder.decode(new ChannelHandlerContextAdapter(), Unpooled.buffer(), list);
+    }
+
+    @Test
+    public void testDecode() throws Exception {
+        LispMessageDecoder decoder = new LispMessageDecoder();
+        ByteBuf requestBuff = getLispMapRequestBuffer();
+        ByteBuf replyBuff = getLispMapReplyBuffer();
+        ByteBuf registerBuff = getLispMapRegisterBuffer();
+        ByteBuf notifyBuff = getLispMapNotifyBuffer();
+
+        List<Object> list = Lists.newArrayList();
+        decoder.decode(new ChannelHandlerContextAdapter(), requestBuff, list);
+        decoder.decode(new ChannelHandlerContextAdapter(), replyBuff, list);
+        decoder.decode(new ChannelHandlerContextAdapter(), registerBuff, list);
+        decoder.decode(new ChannelHandlerContextAdapter(), notifyBuff, list);
+
+        assertThat(list.size(), is(4));
+        assertThat(list.get(0), is(instanceOf(LispMapRequest.class)));
+        assertThat(list.get(1), is(instanceOf(LispMapReply.class)));
+        assertThat(list.get(2), is(instanceOf(LispMapRegister.class)));
+        assertThat(list.get(3), is(instanceOf(LispMapNotify.class)));
+    }
+}

+/*
+ * Copyright 2016-present 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.lisp.msg.protocols;
+
+import io.netty.buffer.ByteBuf;
+
+import static org.onosproject.lisp.msg.protocols.DefaultLispMapReply.ReplyReader;
+import static org.onosproject.lisp.msg.protocols.DefaultLispMapNotify.NotifyReader;
+import static org.onosproject.lisp.msg.protocols.DefaultLispMapRegister.RegisterReader;
+import static org.onosproject.lisp.msg.protocols.DefaultLispMapRequest.RequestReader;
+
+/**
+ * A factory class which helps to instantiate LISP reader class.
+ */
+public final class LispMessageReaderFactory {
+    private static final int TYPE_SHIFT_BIT = 4;
+
+    private LispMessageReaderFactory() {}
+
+    /**
+     * Obtains corresponding LISP message reader.
+     *
+     * @param buffer netty byte buffer
+     * @return LISP message reader
+     */
+    public static LispMessageReader getReader(ByteBuf buffer) {
+        LispMessageReader reader;
+
+        int type = buffer.getByte(0) >> TYPE_SHIFT_BIT;
+        switch (type) {
+            case 1:
+                reader = new RequestReader();
+                break;
+            case 2:
+                reader = new ReplyReader();
+                break;
+            case 3:
+                reader = new RegisterReader();
+                break;
+            case 4:
+                reader = new NotifyReader();
+                break;
+            default:
+                throw new IllegalArgumentException("Unknown LISP message type: " + type);
+        }
+        return reader;
+    }
+}