Modified bgp file name according to naming convention.

Change-Id: I403139b53fbc1a2dba894dfd39720707a52ba7cd
diff --git a/bgp/bgpio/src/main/java/org/onosproject/bgpio/protocol/ver4/BgpKeepaliveMsgVer4.java b/bgp/bgpio/src/main/java/org/onosproject/bgpio/protocol/ver4/BgpKeepaliveMsgVer4.java
new file mode 100644
index 0000000..2c14158
--- /dev/null
+++ b/bgp/bgpio/src/main/java/org/onosproject/bgpio/protocol/ver4/BgpKeepaliveMsgVer4.java
@@ -0,0 +1,157 @@
+/*
+ * 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.bgpio.protocol.ver4;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.onosproject.bgpio.exceptions.BgpParseException;
+import org.onosproject.bgpio.protocol.BgpKeepaliveMsg;
+import org.onosproject.bgpio.protocol.BgpMessageReader;
+import org.onosproject.bgpio.protocol.BgpMessageWriter;
+import org.onosproject.bgpio.types.BgpHeader;
+import org.onosproject.bgpio.protocol.BgpType;
+import org.onosproject.bgpio.protocol.BgpVersion;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.common.base.MoreObjects;
+
+/**
+ * Provides BGP keep alive message.
+ */
+public class BgpKeepaliveMsgVer4 implements BgpKeepaliveMsg {
+
+    /*
+    <Keepalive Message>::= <Common Header>
+    A KEEPALIVE message consists of only the message header and has a
+    length of 19 octets.
+
+    0                   1                   2                   3
+    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                                                               |
+    +                                                               +
+    |                                                               |
+    +                                                               +
+    |                           Marker                              |
+    +                                                               +
+    |                                                               |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |          Length               |      Type     |
+    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+    REFERENCE : RFC 4271
+    */
+
+    protected static final Logger log = LoggerFactory
+            .getLogger(BgpKeepaliveMsgVer4.class);
+
+    private BgpHeader bgpMsgHeader;
+    public static final byte PACKET_VERSION = 4;
+    public static final int PACKET_MINIMUM_LENGTH = 19;
+    public static final int MARKER_LENGTH = 16;
+    public static final BgpType MSG_TYPE = BgpType.KEEP_ALIVE;
+    public static byte[] marker = new byte[] {(byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff,
+                                              (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff,
+                                              (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff,
+                                              (byte) 0xff, (byte) 0xff, (byte) 0xff, (byte) 0xff};
+
+    public static final BgpKeepaliveMsgVer4.Reader READER = new Reader();
+
+    /**
+     * Reader class for reading BGP keepalive message from channel buffer.
+     */
+    static class Reader implements BgpMessageReader<BgpKeepaliveMsg> {
+
+        @Override
+        public BgpKeepaliveMsg readFrom(ChannelBuffer cb, BgpHeader bgpHeader)
+                throws BgpParseException {
+
+            /* bgpHeader is not required in case of keepalive message and
+            Header is already read and no other fields except header in keepalive message.*/
+            return new BgpKeepaliveMsgVer4();
+        }
+    }
+
+    /**
+     * Default constructor.
+     */
+    public BgpKeepaliveMsgVer4() {
+    }
+
+    /**
+     * Builder class for BGP keepalive message.
+     */
+    static class Builder implements BgpKeepaliveMsg.Builder {
+        BgpHeader bgpMsgHeader;
+
+        @Override
+        public Builder setHeader(BgpHeader bgpMsgHeader) {
+            this.bgpMsgHeader = bgpMsgHeader;
+            return this;
+        }
+
+        @Override
+        public BgpKeepaliveMsg build() {
+            return new BgpKeepaliveMsgVer4();
+        }
+    }
+
+    @Override
+    public void writeTo(ChannelBuffer cb) {
+        WRITER.write(cb, this);
+    }
+
+    static final Writer WRITER = new Writer();
+
+    /**
+     * Writer class for writing the BGP keepalive message to channel buffer.
+     */
+    static class Writer implements BgpMessageWriter<BgpKeepaliveMsgVer4> {
+
+        @Override
+        public void write(ChannelBuffer cb, BgpKeepaliveMsgVer4 message) {
+
+            // write marker
+            cb.writeBytes(marker, 0, MARKER_LENGTH);
+
+            // write length of header
+            cb.writeShort(PACKET_MINIMUM_LENGTH);
+
+            // write the type of message
+            cb.writeByte(MSG_TYPE.getType());
+        }
+    }
+
+    @Override
+    public BgpVersion getVersion() {
+        return BgpVersion.BGP_4;
+    }
+
+    @Override
+    public BgpType getType() {
+        return MSG_TYPE;
+    }
+
+    @Override
+    public BgpHeader getHeader() {
+        return this.bgpMsgHeader;
+    }
+
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(getClass()).toString();
+    }
+}