Minor refactoring

Author: Net-burst

src/main/java/org/prebid/server/auction/ExchangeService.java

@@ -584,6 +584,7 @@ private EidPermissionIndex getEidPermissions(ExtRequestPrebid prebid) {
         return Optional.ofNullable(prebid)
                 .map(ExtRequestPrebid::getData)
                 .map(ExtRequestPrebidData::getEidPermissions)
+                .map(CollectionUtils::emptyIfNull)
                 .map(EidPermissionIndex::build)
                 .orElse(null);
     }
@@ -680,10 +681,7 @@ private List<Eid> resolveAllowedEids(List<Eid> userEids, String bidder, EidPermi
     private boolean isUserEidAllowed(Eid eid,
                                      EidPermissionIndex eidPermissionIndex,
                                      String bidder) {
-        if (eidPermissionIndex == null) {
-            return true;
-        }
-        return eidPermissionIndex.isAllowed(eid, bidder);
+        return eidPermissionIndex == null || eidPermissionIndex.isAllowed(eid, bidder);
     }
 
     private List<AuctionParticipation> getAuctionParticipation(

src/main/java/org/prebid/server/auction/model/EidPermissionIndex.java

@@ -6,6 +6,7 @@
 import org.apache.commons.lang3.StringUtils;
 import org.prebid.server.proto.openrtb.ext.request.ExtRequestPrebidDataEidPermissions;
 
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -14,11 +15,11 @@
 
 public final class EidPermissionIndex {
 
-    // bitmask for which fields are present in a permission
-    private static final int INSERTER = 1; // 0001
-    private static final int SOURCE = 2; // 0010
-    private static final int MATCHER = 4; // 0100
-    private static final int MM = 8; // 1000
+    // Bitmask for which fields are present in the EID permission
+    private static final int INSERTER = 1 << 0;
+    private static final int SOURCE = 1 << 1;
+    private static final int MATCHER = 1 << 2;
+    private static final int MM = 1 << 3;
     private static final String WILDCARD_BIDDER = "*";
 
     private final Map<Integer, Map<Key, Set<String>>> ruleIndexByMask;
@@ -30,13 +31,13 @@ private EidPermissionIndex(Map<Integer, Map<Key, Set<String>>> ruleIndexByMask)
         this.ruleIndexByMask = ruleIndexByMask;
     }
 
-    public static EidPermissionIndex build(List<ExtRequestPrebidDataEidPermissions> permissions) {
+    public static EidPermissionIndex build(Collection<ExtRequestPrebidDataEidPermissions> permissions) {
+        final Map<Integer, Map<Key, Set<String>>> idx = new HashMap<>();
+
         if (ObjectUtils.isEmpty(permissions)) {
-            return null;
+            return new EidPermissionIndex(idx);
         }
 
-        final Map<Integer, Map<Key, Set<String>>> idx = new HashMap<>();
-
         for (ExtRequestPrebidDataEidPermissions permission : permissions) {
             final List<String> bidders = CollectionUtils.emptyIfNull(permission.getBidders())
                     .stream()
@@ -66,25 +67,17 @@ public static EidPermissionIndex build(List<ExtRequestPrebidDataEidPermissions>
     }
 
     private static int maskOf(String inserter, String source, String matcher, Integer mm) {
-        int mask = 0;
-
-        if (inserter != null) {
-            mask |= INSERTER;
-        }
-        if (source != null) {
-            mask |= SOURCE;
-        }
-        if (matcher != null) {
-            mask |= MATCHER;
-        }
-        if (mm != null) {
-            mask |= MM;
-        }
-
-        return mask;
+        return (inserter != null ? INSERTER : 0)
+                | (source != null ? SOURCE : 0)
+                | (matcher != null ? MATCHER : 0)
+                | (mm != null ? MM : 0);
     }
 
     public boolean isAllowed(Eid eid, String bidder) {
+        if (ObjectUtils.isEmpty(ruleIndexByMask)) {
+            return true;
+        }
+
         final int eidMask = maskOf(eid.getInserter(), eid.getSource(), eid.getMatcher(), eid.getMm());
 
         boolean ruleMatched = false;
@@ -93,8 +86,7 @@ public boolean isAllowed(Eid eid, String bidder) {
         for (Map.Entry<Integer, Map<Key, Set<String>>> ruleBucket : ruleIndexByMask.entrySet()) {
             final int ruleMask = ruleBucket.getKey();
 
-            // rule can only match if all its required fields exist on the Eid
-            if ((ruleMask & eidMask) != ruleMask) {
+            if (!isMaskMatched(ruleMask, eidMask)) {
                 continue;
             }
 
@@ -112,7 +104,11 @@ public boolean isAllowed(Eid eid, String bidder) {
             }
         }
 
-        // allow-by-default: if no rule matched at all, allow
+        // Allow by default if no rule matched at all
         return !ruleMatched;
     }
+
+    private boolean isMaskMatched(int ruleMaks, int eidMask) {
+        return (ruleMaks & eidMask) == ruleMaks;
+    }
 }