Added kryo serializer for ImmutableByteSequence

Serialization was failing when the inner ByteBuffer instance was a
HeapByteBuffer. Also, simplified ImmutableByteSequence.toString()

Change-Id: I4f75086a9b6536205fb43b78a0e4d2bfce9e8a5c

+/*
+ * 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.store.serializers;
+
+import com.esotericsoftware.kryo.Kryo;
+import com.esotericsoftware.kryo.Serializer;
+import com.esotericsoftware.kryo.io.Input;
+import com.esotericsoftware.kryo.io.Output;
+import org.onlab.util.ImmutableByteSequence;
+
+/**
+ * Kryo serializer for {@link ImmutableByteSequence}.
+ */
+public class ImmutableByteSequenceSerializer extends Serializer<ImmutableByteSequence> {
+
+    /**
+     * Creates a new {@link ImmutableByteSequence} serializer instance.
+     */
+    public ImmutableByteSequenceSerializer() {
+        // non-null, immutable.
+        super(false, true);
+    }
+
+    @Override
+    public void write(Kryo kryo, Output output, ImmutableByteSequence object) {
+        byte[] data = object.asArray();
+        output.writeInt(data.length);
+        output.write(data);
+    }
+
+    @Override
+    public ImmutableByteSequence read(Kryo kryo, Input input, Class<ImmutableByteSequence> type) {
+        int length = input.readInt();
+        byte[] data = new byte[length];
+        input.read(data);
+        return ImmutableByteSequence.copyFrom(data);
+    }
+}

@@ -534,7 +534,7 @@ public final class KryoNamespaces {
             )
             .register(ClosedOpenRange.class)
             .register(DiscreteResourceCodec.class)
-            .register(ImmutableByteSequence.class)
+            .register(new ImmutableByteSequenceSerializer(), ImmutableByteSequence.class)
             .build("API");
 
 

@@ -16,7 +16,6 @@
 
 package org.onlab.util;
 
-import com.google.common.base.MoreObjects;
 import com.google.common.base.Objects;
 
 import java.nio.ByteBuffer;
@@ -238,8 +237,6 @@ public final class ImmutableByteSequence {
 
     @Override
     public String toString() {
-        return MoreObjects.toStringHelper(this)
-                .addValue(HexString.toHexString(asArray()))
-                .toString();
+        return HexString.toHexString(value.array());
     }
 }
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