Merge "Avoiding hash collisions of a match with its reverse"

diff --git a/opendaylight/sal/api/src/main/java/org/opendaylight/controller/sal/match/Match.java b/opendaylight/sal/api/src/main/java/org/opendaylight/controller/sal/match/Match.java
index 2c3cfb8303736229e6c86b618642f6bd72b12aaa..910695c1e9cbc0ebcfb121b621fb7187305aff37 100644 (file)
--- a/opendaylight/sal/api/src/main/java/org/opendaylight/controller/sal/match/Match.java
+++ b/opendaylight/sal/api/src/main/java/org/opendaylight/controller/sal/match/Match.java
@@ -20,6 +20,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
+import java.util.TreeMap;
 
 import javax.xml.bind.annotation.XmlAccessType;
 import javax.xml.bind.annotation.XmlAccessorType;
@@ -444,13 +445,16 @@ public class Match implements Cloneable, Serializable {
         if (this.fields == null) {
             result = prime * result;
         } else {
-            int sum = 0;
-            for (MatchType field : this.fields.keySet()) {
-                MatchField f = this.fields.get(field);
-                sum = sum + ((field==null ? 0 : field.calculateConsistentHashCode()) ^
-                             (f==null ? 0 : f.hashCode()));
+            // use a tree map as the order of hashMap is not guaranteed.
+            // 2 Match objects with fields in different order are still equal.
+            // Hence the hashCode should be the same too.
+            TreeMap<MatchType, MatchField> tm = new TreeMap<MatchType, MatchField>(this.fields);
+            for (MatchType field : tm.keySet()) {
+                MatchField f = tm.get(field);
+                int fieldHashCode = (field==null ? 0 : field.calculateConsistentHashCode()) ^
+                             (f==null ? 0 : f.hashCode());
+                result = prime * result + fieldHashCode;
             }
-            result = prime * result + sum;
         }
         result = prime * result + matches;
         return result;

diff --git a/opendaylight/sal/api/src/test/java/org/opendaylight/controller/sal/match/MatchTest.java b/opendaylight/sal/api/src/test/java/org/opendaylight/controller/sal/match/MatchTest.java
index 30d49cfd9dcc5b5abb90bafd659ac314e855f99a..b88ae034d9aa713c96f4ce3ef633f977d5a223b3 100644 (file)
--- a/opendaylight/sal/api/src/test/java/org/opendaylight/controller/sal/match/MatchTest.java
+++ b/opendaylight/sal/api/src/test/java/org/opendaylight/controller/sal/match/MatchTest.java
@@ -337,6 +337,21 @@ public class MatchTest {
         Assert.assertTrue(match1.equals(match2));
     }
 
+    @Test
+    public void testHashCodeWithReverseMatch() throws Exception {
+        InetAddress srcIP1 = InetAddress.getByName("1.1.1.1");
+        InetAddress ipMask1 = InetAddress.getByName("255.255.255.255");
+        InetAddress srcIP2 = InetAddress.getByName("2.2.2.2");
+        InetAddress ipMask2 = InetAddress.getByName("255.255.255.255");
+        MatchField field1 = new MatchField(MatchType.NW_SRC, srcIP1, ipMask1);
+        MatchField field2 = new MatchField(MatchType.NW_DST, srcIP2, ipMask2);
+        Match match1 = new Match();
+        match1.setField(field1);
+        match1.setField(field2);
+        Match match2 = match1.reverse();
+        Assert.assertFalse(match1.hashCode() == match2.hashCode());
+    }
+
     @Test
     public void testHashCode() throws Exception {
         byte srcMac1[] = { (byte) 0x12, (byte) 0x34, (byte) 0x56, (byte) 0x78, (byte) 0x9a, (byte) 0xbc };