commit bfc2e92c976b0febeaebf92d4b8e99f7f262bbaf
author Yuta HIGUCHI <y-higuchi@ak.jp.nec.com> Wed Jun 07 21:46:05 2017 -0700
committer Yuta HIGUCHI <y-higuchi@onlab.us> Fri Jun 09 00:20:52 2017 +0000
tree 280dc69cd987e6d282646898c21768f690006b46
parent 537fe85b8b413fc016681f054e619bf63122d911

Ensure immutability of constants Collection

Change-Id: I9b26282ccabaef5e4ac81fb626abfa6e537d9333

utils/misc/src/main/java/org/onlab/packet/IPv4.java

diff --git a/utils/misc/src/main/java/org/onlab/packet/IPv4.java b/utils/misc/src/main/java/org/onlab/packet/IPv4.java
index 95695dc..b79a947 100644
--- a/utils/misc/src/main/java/org/onlab/packet/IPv4.java
+++ b/utils/misc/src/main/java/org/onlab/packet/IPv4.java
@@ -19,9 +19,10 @@
 import java.nio.ByteBuffer;
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.HashMap;
 import java.util.Map;
 
+import com.google.common.collect.ImmutableMap;
+
 import static com.google.common.base.MoreObjects.toStringHelper;
 import static org.onlab.packet.PacketUtils.*;
 
@@ -35,15 +36,14 @@
     public static final byte PROTOCOL_UDP = 0x11;
     public static final byte PROTOCOL_PIM = 0x67;
     public static final Map<Byte, Deserializer<? extends IPacket>> PROTOCOL_DESERIALIZER_MAP =
-            new HashMap<>();
+            ImmutableMap.<Byte, Deserializer<? extends IPacket>>builder()
+                .put(IPv4.PROTOCOL_ICMP, ICMP.deserializer())
+                .put(IPv4.PROTOCOL_IGMP, IGMP.deserializer())
+                .put(IPv4.PROTOCOL_TCP, TCP.deserializer())
+                .put(IPv4.PROTOCOL_UDP, UDP.deserializer())
+                .put(IPv4.PROTOCOL_PIM, PIM.deserializer())
+                .build();
 
-    static {
-        IPv4.PROTOCOL_DESERIALIZER_MAP.put(IPv4.PROTOCOL_ICMP, ICMP.deserializer());
-        IPv4.PROTOCOL_DESERIALIZER_MAP.put(IPv4.PROTOCOL_IGMP, IGMP.deserializer());
-        IPv4.PROTOCOL_DESERIALIZER_MAP.put(IPv4.PROTOCOL_TCP, TCP.deserializer());
-        IPv4.PROTOCOL_DESERIALIZER_MAP.put(IPv4.PROTOCOL_UDP, UDP.deserializer());
-        IPv4.PROTOCOL_DESERIALIZER_MAP.put(IPv4.PROTOCOL_PIM, PIM.deserializer());
-    }
 
     private static final byte DSCP_MASK = 0x3f;
     private static final byte DSCP_OFFSET = 2;