15: Check returned data before decoding

src/main/tjava/com/r35157/libs/jupiter/perps/impl/anchoridl/AnchorIdlJupiterPerpsPositionServiceImpl.tjava

@@ -52,15 +52,25 @@ public class AnchorIdlJupiterPerpsPositionServiceImpl implements JupiterPerpsPos
         Set<JupiterPerpsPosition> positions = new HashSet<>();
 
         for (SolanaAccountInfo accountInfo : accountInfos) {
+            ΩSolanaAddressΩ address = accountInfo.address();
+            ΩSolanaProgramIdΩ programId = accountInfo.owner();
+
+            if (!JUPITER_PERPS_PROGRAM_ID.equals(programId)) {
+                String errorMsg = "Account '" + address + "' is not owned by Jupiter Perps program '" +
+                        programId + "'";
+                throw new IllegalArgumentException(errorMsg);
+            }
+
             JupiterPerpsPosition position = positionDecoder.decode(
-                accountInfo.address(),
+                    address,
                     accountInfo
             );
             positions.add(position);
         }
 
         return Set.copyOf(positions);
-}
+    }
+
     private static final ΩJupiterPerpsProgramIdΩ JUPITER_PERPS_PROGRAM_ID =
             "PERPHjGBqRHArX4DySjwM6UJHiR3sWAatqfdBS2qQJu";
     private static final int POSITION_OWNER_OFFSET = 8;