Refactor IE parsing (#90)

src/main/java/com/facebook/openwifirrm/ucentral/InformationElements.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.facebook.openwifirrm.ucentral;
+
+import java.util.Objects;
+
+import com.facebook.openwifirrm.ucentral.informationelement.Country;
+import com.facebook.openwifirrm.ucentral.informationelement.LocalPowerConstraint;
+import com.facebook.openwifirrm.ucentral.informationelement.QbssLoad;
+import com.facebook.openwifirrm.ucentral.informationelement.TxPwrInfo;
+
+/** Wrapper class containing information elements */
+public final class InformationElements {
+
+	public Country country;
+	public QbssLoad qbssLoad;
+	public LocalPowerConstraint localPowerConstraint;
+	public TxPwrInfo txPwrInfo;
+
+	@Override
+	public int hashCode() {
+		return Objects.hash(country, localPowerConstraint, qbssLoad, txPwrInfo);
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj) {
+			return true;
+		}
+		if (obj == null) {
+			return false;
+		}
+		if (getClass() != obj.getClass()) {
+			return false;
+		}
+		InformationElements other = (InformationElements) obj;
+		return Objects.equals(country, other.country) && Objects.equals(
+			localPowerConstraint,
+			other.localPowerConstraint
+		) && Objects.equals(qbssLoad, other.qbssLoad) &&
+			Objects.equals(txPwrInfo, other.txPwrInfo);
+	}
+
+}

src/main/java/com/facebook/openwifirrm/ucentral/UCentralUtils.java

@@ -111,8 +111,9 @@ public class UCentralUtils {
 			logger.debug("Wifiscan entry does not contain 'ies' field.");
 			return;
 		}
-		JsonArray ies = iesJsonElement.getAsJsonArray();
-		for (JsonElement ie : ies) {
+		JsonArray iesJsonArray = iesJsonElement.getAsJsonArray();
+		InformationElements ieContainer = new InformationElements();
+		for (JsonElement ie : iesJsonArray) {
 			JsonElement typeElement = ie.getAsJsonObject().get("type");
 			if (typeElement == null) {
 				continue;
@@ -122,23 +123,25 @@ public class UCentralUtils {
 			try {
 				switch (typeElement.getAsInt()) {
 				case Country.TYPE:
-					entry.country = Country.parse(contents);
+					ieContainer.country = Country.parse(contents);
 					break;
 				case QbssLoad.TYPE:
-					entry.qbssLoad = QbssLoad.parse(contents);
+					ieContainer.qbssLoad = QbssLoad.parse(contents);
 					break;
 				case LocalPowerConstraint.TYPE:
-					entry.localPowerConstraint =
+					ieContainer.localPowerConstraint =
 						LocalPowerConstraint.parse(contents);
 					break;
 				case TxPwrInfo.TYPE:
-					entry.txPwrInfo = TxPwrInfo.parse(contents);
+					ieContainer.txPwrInfo = TxPwrInfo.parse(contents);
 					break;
 				}
-			} catch (NullPointerException e) {
+			} catch (Exception e) {
 				logger.debug("Skipping invalid IE.", e);
+				continue;
 			}
 		}
+		entry.ieContainer = ieContainer;
 	}
 
 	/**

src/main/java/com/facebook/openwifirrm/ucentral/WifiScanEntry.java

@@ -10,10 +10,6 @@ package com.facebook.openwifirrm.ucentral;
 
 import java.util.Objects;
 
-import com.facebook.openwifirrm.ucentral.informationelement.Country;
-import com.facebook.openwifirrm.ucentral.informationelement.LocalPowerConstraint;
-import com.facebook.openwifirrm.ucentral.informationelement.QbssLoad;
-import com.facebook.openwifirrm.ucentral.informationelement.TxPwrInfo;
 import com.facebook.openwifirrm.ucentral.models.WifiScanEntryResult;
 
 /**
@@ -26,10 +22,8 @@ public class WifiScanEntry extends WifiScanEntryResult {
 	 * time reference.
 	 */
 	public long unixTimeMs;
-	public Country country;
-	public QbssLoad qbssLoad;
-	public LocalPowerConstraint localPowerConstraint;
-	public TxPwrInfo txPwrInfo;
+	/** Stores Information Elements (IEs) from the wifiscan entry. */
+	public InformationElements ieContainer;
 
 	/** Default Constructor. */
 	public WifiScanEntry() {}
@@ -38,23 +32,14 @@ public class WifiScanEntry extends WifiScanEntryResult {
 	public WifiScanEntry(WifiScanEntry o) {
 		super(o);
 		this.unixTimeMs = o.unixTimeMs;
-		this.country = o.country;
-		this.qbssLoad = o.qbssLoad;
-		this.localPowerConstraint = o.localPowerConstraint;
-		this.txPwrInfo = o.txPwrInfo;
+		this.ieContainer = o.ieContainer;
 	}
 
 	@Override
 	public int hashCode() {
 		final int prime = 31;
 		int result = super.hashCode();
-		result = prime * result + Objects.hash(
-			country,
-			localPowerConstraint,
-			qbssLoad,
-			txPwrInfo,
-			unixTimeMs
-		);
+		result = prime * result + Objects.hash(ieContainer, unixTimeMs);
 		return result;
 	}
 
@@ -70,11 +55,7 @@ public class WifiScanEntry extends WifiScanEntryResult {
 			return false;
 		}
 		WifiScanEntry other = (WifiScanEntry) obj;
-		return Objects.equals(country, other.country) && Objects.equals(
-			localPowerConstraint,
-			other.localPowerConstraint
-		) && Objects.equals(qbssLoad, other.qbssLoad) && Objects
-			.equals(txPwrInfo, other.txPwrInfo) &&
+		return Objects.equals(ieContainer, other.ieContainer) &&
 			unixTimeMs == other.unixTimeMs;
 	}
 
@@ -87,5 +68,4 @@ public class WifiScanEntry extends WifiScanEntryResult {
 			unixTimeMs
 		);
 	}
-
 }

src/main/java/com/facebook/openwifirrm/ucentral/informationelement/Country.java

@@ -30,6 +30,7 @@ public class Country {
 	/** Defined in 802.11 */
 	public static final int TYPE = 7;
 
+	/** Constraints for a subset of channels in the AP's country */
 	public static class CountryInfo {
 		/**
 		 * The lowest channel number in the CountryInfo.
@@ -124,15 +125,9 @@ public class Country {
 		JsonElement constraintsObject = contents.get("constraints");
 		if (constraintsObject != null) {
 			for (JsonElement jsonElement : constraintsObject.getAsJsonArray()) {
-				try {
-					constraints
-						.add(CountryInfo.parse(jsonElement.getAsJsonObject()));
-				} catch (NullPointerException e) {
-					logger.debug(
-						"Skipping invalid constraint encountered in Country IE.",
-						e
-					);
-				}
+				CountryInfo countryInfo =
+					CountryInfo.parse(jsonElement.getAsJsonObject());
+				constraints.add(countryInfo);
 			}
 		}
 		return new Country(constraints);

src/main/java/com/facebook/openwifirrm/ucentral/informationelement/QbssLoad.java

@@ -10,6 +10,7 @@ package com.facebook.openwifirrm.ucentral.informationelement;
 
 import java.util.Objects;
 
+import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 
 /**
@@ -61,9 +62,14 @@ public class QbssLoad {
 		this.availableAdmissionCapacity = availableAdmissionCapacity;
 	}
 
-	/** Parse QbssLoad IE from appropriate Json object. */
+	/** Parse QbssLoad IE from appropriate Json object; return null if invalid. */
 	public static QbssLoad parse(JsonObject contents) {
-		contents = contents.get("802.11e CCA Version").getAsJsonObject();
+		// unclear why there is this additional nested layer
+		JsonElement ccaContentJsonElement = contents.get("802.11e CCA Version");
+		if (ccaContentJsonElement == null) {
+			return null;
+		}
+		contents = ccaContentJsonElement.getAsJsonObject();
 		final int stationCount = contents.get("Station Count").getAsInt();
 		final int channelUtilization =
 			contents.get("Channel Utilization").getAsInt();