[onos-2603] - Implement LinkState Link attributes-Opaque Link attr

Change-Id: Idfc1f7a5f9f54234b6f0f7c7f50c14f6f3f76b57

+/*
+ * 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 java.util.Arrays;
+
+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 link opaque attribute.
+ */
+public final class BgpLinkAttrOpaqLnkAttrib implements BGPValueType {
+
+    protected static final Logger log = LoggerFactory
+            .getLogger(BgpLinkAttrOpaqLnkAttrib.class);
+
+    public static final int ATTRNODE_OPAQUELNKATTRIB = 1097;
+
+    /* Opaque Node Attribute */
+    private final byte[] opaqueLinkAttribute;
+
+    /**
+     * Constructor to initialize the data.
+     *
+     * @param opaqueLinkAttribute opaque link attribute
+     */
+    private BgpLinkAttrOpaqLnkAttrib(byte[] opaqueLinkAttribute) {
+        this.opaqueLinkAttribute = Arrays.copyOf(opaqueLinkAttribute,
+                                                 opaqueLinkAttribute.length);
+    }
+
+    /**
+     * Returns object of this class with specified values.
+     *
+     * @param opaqueLinkAttribute opaque link attribute
+     * @return object of BgpLinkAttrOpaqLnkAttrib
+     */
+    public static BgpLinkAttrOpaqLnkAttrib of(final byte[] opaqueLinkAttribute) {
+        return new BgpLinkAttrOpaqLnkAttrib(opaqueLinkAttribute);
+    }
+
+    /**
+     * Reads the BGP link attributes Opaque link attribute.
+     *
+     * @param cb Channel buffer
+     * @return object of type BgpLinkAttrOpaqLnkAttrib
+     * @throws BGPParseException while parsing BgpLinkAttrOpaqLnkAttrib
+     */
+    public static BgpLinkAttrOpaqLnkAttrib read(ChannelBuffer cb)
+            throws BGPParseException {
+
+        byte[] opaqueLinkAttribute;
+
+        short lsAttrLength = cb.readShort();
+
+        if (cb.readableBytes() < lsAttrLength) {
+            Validation.validateLen(BGPErrorType.UPDATE_MESSAGE_ERROR,
+                                   BGPErrorType.ATTRIBUTE_LENGTH_ERROR,
+                                   lsAttrLength);
+        }
+
+        opaqueLinkAttribute = new byte[lsAttrLength];
+        cb.readBytes(opaqueLinkAttribute);
+
+        return BgpLinkAttrOpaqLnkAttrib.of(opaqueLinkAttribute);
+    }
+
+    /**
+     * Returns the Opaque link attribute.
+     *
+     * @return byte array of opaque link attribute.
+     */
+    public byte[] attrOpaqueLnk() {
+        return opaqueLinkAttribute;
+    }
+
+    @Override
+    public short getType() {
+        return ATTRNODE_OPAQUELNKATTRIB;
+    }
+
+    @Override
+    public int hashCode() {
+        return Arrays.hashCode(opaqueLinkAttribute);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+
+        if (obj instanceof BgpLinkAttrOpaqLnkAttrib) {
+            BgpLinkAttrOpaqLnkAttrib other = (BgpLinkAttrOpaqLnkAttrib) obj;
+            return Arrays
+                    .equals(opaqueLinkAttribute, other.opaqueLinkAttribute);
+        }
+        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("opaqueLinkAttribute", opaqueLinkAttribute).toString();
+    }
+}