[Emu][onos-2603] - Implement LinkState Link attributes-Opaque Prefix Data

Change-Id: I79a4ee63afe2da8b3c2a660bfb24f99ed39eda2f

+/*
+ * 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 prefix opaque data attribute.
+ */
+public final class BgpPrefixAttrOpaqueData implements BGPValueType {
+
+    protected static final Logger log = LoggerFactory
+            .getLogger(BgpPrefixAttrOpaqueData.class);
+
+    public static final int ATTR_PREFIX_OPAQUEDATA = 1157;
+
+    /* Opaque Node Attribute */
+    private final byte[] opaquePrefixAttribute;
+
+    /**
+     * Constructor to initialize the values.
+     *
+     * @param opaquePrefixAttribute opaque prefix data
+     */
+    public BgpPrefixAttrOpaqueData(byte[] opaquePrefixAttribute) {
+        this.opaquePrefixAttribute = Arrays
+                .copyOf(opaquePrefixAttribute, opaquePrefixAttribute.length);
+    }
+
+    /**
+     * Returns object of this class with specified values.
+     *
+     * @param opaquePrefixAttribute opaque prefix data
+     * @return object of BgpPrefixAttrOpaqueData
+     */
+    public static BgpPrefixAttrOpaqueData of(final byte[] opaquePrefixAttribute) {
+        return new BgpPrefixAttrOpaqueData(opaquePrefixAttribute);
+    }
+
+    /**
+     * Reads the Opaque Prefix Attribute.
+     *
+     * @param cb ChannelBuffer
+     * @return object of BgpPrefixAttrOpaqueData
+     * @throws BGPParseException while parsing BgpPrefixAttrOpaqueData
+     */
+    public static BgpPrefixAttrOpaqueData read(ChannelBuffer cb)
+            throws BGPParseException {
+        byte[] opaquePrefixAttribute;
+
+        short lsAttrLength = cb.readShort();
+        opaquePrefixAttribute = new byte[lsAttrLength];
+
+        if (cb.readableBytes() < lsAttrLength) {
+            Validation.validateLen(BGPErrorType.UPDATE_MESSAGE_ERROR,
+                                   BGPErrorType.ATTRIBUTE_LENGTH_ERROR,
+                                   lsAttrLength);
+        }
+
+        cb.readBytes(opaquePrefixAttribute);
+
+        return BgpPrefixAttrOpaqueData.of(opaquePrefixAttribute);
+    }
+
+    /**
+     * Returns the Opaque prefix attribute name.
+     *
+     * @return opaque prefix name
+     */
+    public byte[] getOpaquePrefixAttribute() {
+        return opaquePrefixAttribute;
+    }
+
+    @Override
+    public short getType() {
+        return ATTR_PREFIX_OPAQUEDATA;
+    }
+
+    @Override
+    public int hashCode() {
+        return Arrays.hashCode(opaquePrefixAttribute);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+
+        if (obj instanceof BgpPrefixAttrOpaqueData) {
+            BgpPrefixAttrOpaqueData other = (BgpPrefixAttrOpaqueData) obj;
+            return Arrays.equals(opaquePrefixAttribute,
+                                 other.opaquePrefixAttribute);
+        }
+        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("opaquePrefixAttribute", getOpaquePrefixAttribute())
+                .toString();
+    }
+
+}