[onos-2603] - Implement LinkState Link attributes-EXT Route Tag

Change-Id: Ieeab8f46b81e55c0dc4ec89e8578cc1f34602875

+/*
+ * 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.types.attr;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.onosproject.bgpio.exceptions.BGPParseException;
+import org.onosproject.bgpio.types.BGPErrorType;
+import org.onosproject.bgpio.types.BGPValueType;
+import org.onosproject.bgpio.util.Validation;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.common.base.MoreObjects;
+
+/**
+ * Implements BGP prefix route Extended tag attribute.
+ */
+public class BgpPrefixAttrExtRouteTag implements BGPValueType {
+
+    protected static final Logger log = LoggerFactory
+            .getLogger(BgpPrefixAttrExtRouteTag.class);
+
+    public static final int ATTR_PREFIX_EXTROUTETAG = 1154;
+    public static final int ATTR_PREFIX_EXT_LEN = 8;
+
+    /* Prefix Route Tag */
+    private List<Long> pfxExtRouteTag = new ArrayList<Long>();
+
+    /**
+     * Constructor to initialize the values.
+     *
+     * @param pfxExtRouteTag Extended route tag
+     */
+    public BgpPrefixAttrExtRouteTag(List<Long> pfxExtRouteTag) {
+        this.pfxExtRouteTag = checkNotNull(pfxExtRouteTag);
+    }
+
+    /**
+     * Returns object of this class with specified values.
+     *
+     * @param pfxExtRouteTag Prefix Metric
+     * @return object of BgpPrefixAttrMetric
+     */
+    public static BgpPrefixAttrExtRouteTag of(ArrayList<Long> pfxExtRouteTag) {
+        return new BgpPrefixAttrExtRouteTag(pfxExtRouteTag);
+    }
+
+    /**
+     * Reads the Extended Tag.
+     *
+     * @param cb ChannelBuffer
+     * @return object of BgpPrefixAttrExtRouteTag
+     * @throws BGPParseException while parsing BgpPrefixAttrExtRouteTag
+     */
+    public static BgpPrefixAttrExtRouteTag read(ChannelBuffer cb)
+            throws BGPParseException {
+        ArrayList<Long> pfxExtRouteTag = new ArrayList<Long>();
+        long temp;
+
+        short lsAttrLength = cb.readShort();
+        int len = lsAttrLength / ATTR_PREFIX_EXT_LEN;
+
+        if (cb.readableBytes() < lsAttrLength) {
+            Validation.validateLen(BGPErrorType.UPDATE_MESSAGE_ERROR,
+                                   BGPErrorType.ATTRIBUTE_LENGTH_ERROR,
+                                   lsAttrLength);
+        }
+
+        for (int i = 0; i < len; i++) {
+            temp = cb.readLong();
+            pfxExtRouteTag.add(new Long(temp));
+        }
+
+        return new BgpPrefixAttrExtRouteTag(pfxExtRouteTag);
+    }
+
+    /**
+     * Returns Extended route tag.
+     *
+     * @return route tag
+     */
+    public List<Long> pfxExtRouteTag() {
+        return pfxExtRouteTag;
+    }
+
+    @Override
+    public short getType() {
+        return ATTR_PREFIX_EXTROUTETAG;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(pfxExtRouteTag);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+
+        if (obj instanceof BgpPrefixAttrExtRouteTag) {
+            BgpPrefixAttrExtRouteTag other = (BgpPrefixAttrExtRouteTag) obj;
+            return Objects.equals(pfxExtRouteTag, other.pfxExtRouteTag);
+        }
+        return false;
+    }
+
+    @Override
+    public int write(ChannelBuffer cb) {
+        // TODO This will be implemented in the next version
+        return 0;
+    }
+
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(getClass()).omitNullValues()
+                .add("pfxExtRouteTag", pfxExtRouteTag).toString();
+    }
+}