Match field iteration
diff --git a/java_gen/templates/_imports.java b/java_gen/templates/_imports.java
index 2187bab..cf7334d 100644
--- a/java_gen/templates/_imports.java
+++ b/java_gen/templates/_imports.java
@@ -1,6 +1,7 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.EnumSet;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Set;
 import java.util.Map;
@@ -21,5 +22,6 @@
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Sets;
+import com.google.common.collect.UnmodifiableIterator;
 import com.google.common.hash.Funnel;
 import com.google.common.hash.PrimitiveSink;
diff --git a/java_gen/templates/custom/OFMatchV1Ver10.java b/java_gen/templates/custom/OFMatchV1Ver10.java
index 82ff10f..7b750bb 100644
--- a/java_gen/templates/custom/OFMatchV1Ver10.java
+++ b/java_gen/templates/custom/OFMatchV1Ver10.java
@@ -334,3 +334,77 @@
                 throw new UnsupportedOperationException("OFMatch does not support masked matching on field " + field.getName());
         }
     }
+
+    @Override
+    public Iterable<MatchField<?>> getMatchFields() {
+        ImmutableList.Builder<MatchField<?>> builder = ImmutableList.builder();
+        if ((wildcards & OFPFW_IN_PORT) == 0)
+            builder.add(MatchField.IN_PORT);
+        if ((wildcards & OFPFW_DL_VLAN) == 0)
+            builder.add(MatchField.VLAN_VID);
+        if ((wildcards & OFPFW_DL_SRC) == 0)
+            builder.add(MatchField.ETH_SRC);
+        if ((wildcards & OFPFW_DL_DST) == 0)
+            builder.add(MatchField.ETH_DST);
+        if ((wildcards & OFPFW_DL_TYPE) == 0)
+            builder.add(MatchField.ETH_TYPE);
+        if ((wildcards & OFPFW_NW_PROTO) == 0) {
+            if (ethType == EthType.ARP) {
+                builder.add(MatchField.ARP_OP);
+            } else if (ethType == EthType.IPv4) {
+                builder.add(MatchField.IP_PROTO);
+            } else {
+                throw new UnsupportedOperationException(
+                        "Unsupported Ethertype for matching on network protocol " + ethType);
+            }
+        }
+        if ((wildcards & OFPFW_TP_SRC) == 0) {
+            if (ipProto == IpProtocol.UDP) {
+                builder.add(MatchField.UDP_SRC);
+            } else if (ipProto == IpProtocol.TCP) {
+                builder.add(MatchField.TCP_SRC);
+            } else if (ipProto == IpProtocol.SCTP) {
+                builder.add(MatchField.SCTP_SRC);
+            } else {
+                throw new UnsupportedOperationException(
+                        "Unsupported IP protocol for matching on source port " + ipProto);
+            }
+        }
+        if ((wildcards & OFPFW_TP_DST) == 0) {
+            if (ipProto == IpProtocol.UDP) {
+                builder.add(MatchField.UDP_DST);
+            } else if (ipProto == IpProtocol.TCP) {
+                builder.add(MatchField.TCP_DST);
+            } else if (ipProto == IpProtocol.SCTP) {
+                builder.add(MatchField.SCTP_DST);
+            } else {
+                throw new UnsupportedOperationException(
+                        "Unsupported IP protocol for matching on destination port " + ipProto);
+            }
+        }
+        if (((wildcards & OFPFW_NW_SRC_MASK) >> OFPFW_NW_SRC_SHIFT) < 32) {
+            if (ethType == EthType.ARP) {
+                builder.add(MatchField.ARP_SPA);
+            } else if (ethType == EthType.IPv4) {
+                builder.add(MatchField.IPV4_SRC);
+            } else {
+                throw new UnsupportedOperationException(
+                        "Unsupported Ethertype for matching on source IP " + ethType);
+            }
+        }
+        if (((wildcards & OFPFW_NW_DST_MASK) >> OFPFW_NW_DST_SHIFT) < 32) {
+            if (ethType == EthType.ARP) {
+                builder.add(MatchField.ARP_TPA);
+            } else if (ethType == EthType.IPv4) {
+                builder.add(MatchField.IPV4_DST);
+            } else {
+                throw new UnsupportedOperationException(
+                        "Unsupported Ethertype for matching on destination IP " + ethType);
+            }
+        }
+        if ((wildcards & OFPFW_DL_VLAN_PCP) == 0)
+            builder.add(MatchField.VLAN_PCP);
+        if ((wildcards & OFPFW_NW_TOS) == 0)
+            builder.add(MatchField.IP_DSCP);
+        return builder.build();
+    }
diff --git a/java_gen/templates/custom/OFMatchV2Ver11.java b/java_gen/templates/custom/OFMatchV2Ver11.java
index ec7bfcc..ef79ffb 100644
--- a/java_gen/templates/custom/OFMatchV2Ver11.java
+++ b/java_gen/templates/custom/OFMatchV2Ver11.java
@@ -42,3 +42,8 @@
         // FIXME yotam - please replace with real implementation
         return false;
     }
+
+    @Override
+    public Iterable<MatchField<?>> getMatchFields() {
+        throw new UnsupportedOperationException();
+    }
diff --git a/java_gen/templates/custom/OFMatchV3Ver12.java b/java_gen/templates/custom/OFMatchV3Ver12.java
index a4cc51c..81092c1 100644
--- a/java_gen/templates/custom/OFMatchV3Ver12.java
+++ b/java_gen/templates/custom/OFMatchV3Ver12.java
@@ -106,4 +106,9 @@
         OFOxm<?> oxm = this.oxmList.get(field);
 
         return oxm != null && oxm.isMasked();
-    }
\ No newline at end of file
+    }
+
+    @Override
+    public Iterable<MatchField<?>> getMatchFields() {
+        throw new UnsupportedOperationException();
+    }
diff --git a/java_gen/templates/custom/OFMatchV3Ver13.java b/java_gen/templates/custom/OFMatchV3Ver13.java
index 8955e1e..9bfb234 100644
--- a/java_gen/templates/custom/OFMatchV3Ver13.java
+++ b/java_gen/templates/custom/OFMatchV3Ver13.java
@@ -108,3 +108,31 @@
 
         return oxm != null && oxm.isMasked();
     }
+
+    private class MatchFieldIterator extends UnmodifiableIterator<MatchField<?>> {
+        private Iterator<OFOxm<?>> oxmIterator;
+
+        MatchFieldIterator() {
+            oxmIterator = oxmList.iterator();
+        }
+
+        @Override
+        public boolean hasNext() {
+            return oxmIterator.hasNext();
+        }
+
+        @Override
+        public MatchField<?> next() {
+            OFOxm<?> next = oxmIterator.next();
+            return next.getMatchField();
+        }
+    }
+
+    @Override
+    public Iterable<MatchField<?>> getMatchFields() {
+        return new Iterable<MatchField<?>>() {
+            public Iterator<MatchField<?>> iterator() {
+                return new MatchFieldIterator();
+            }
+        };
+    }