MacAddress: add @NonNull annotations

This patch adds to the MacAddress class:
  - getAddressType() method which replaces addressType(), for naming
  consistency
  - @NonNull annotations on all input and output reference values for
  all public methods (@hide and public).

TYPE_UNKNOWN, which currently cannot be observed with a non @hide
method, is also removed from the public api.

Bug: 71866627
Test: $ runtest frameworks-net
Change-Id: I2af70408d46f431b7b32183e6b48ddae9a261a2c

core/java/android/net/MacAddress.java

@@ -17,6 +17,7 @@
 package android.net;
 
 import android.annotation.IntDef;
+import android.annotation.NonNull;
 import android.os.Parcel;
 import android.os.Parcelable;
 
@@ -60,7 +61,7 @@ public final class MacAddress implements Parcelable {
     })
     public @interface MacAddressType { }
 
-    /** Indicates a MAC address of unknown type. */
+    /** @hide Indicates a MAC address of unknown type. */
     public static final int TYPE_UNKNOWN = 0;
     /** Indicates a MAC address is a unicast address. */
     public static final int TYPE_UNICAST = 1;
@@ -92,7 +93,7 @@ public final class MacAddress implements Parcelable {
      *
      * @return the int constant representing the MAC address type of this MacAddress.
      */
-    public @MacAddressType int addressType() {
+    public @MacAddressType int getAddressType() {
         if (equals(BROADCAST_ADDRESS)) {
             return TYPE_BROADCAST;
         }
@@ -120,12 +121,12 @@ public final class MacAddress implements Parcelable {
     /**
      * @return a byte array representation of this MacAddress.
      */
-    public byte[] toByteArray() {
+    public @NonNull byte[] toByteArray() {
         return byteAddrFromLongAddr(mAddr);
     }
 
     @Override
-    public String toString() {
+    public @NonNull String toString() {
         return stringAddrFromLongAddr(mAddr);
     }
 
@@ -133,7 +134,7 @@ public final class MacAddress implements Parcelable {
      * @return a String representation of the OUI part of this MacAddress made of 3 hexadecimal
      * numbers in [0,ff] joined by ':' characters.
      */
-    public String toOuiString() {
+    public @NonNull String toOuiString() {
         return String.format(
                 "%02x:%02x:%02x", (mAddr >> 40) & 0xff, (mAddr >> 32) & 0xff, (mAddr >> 24) & 0xff);
     }
@@ -197,7 +198,7 @@ public final class MacAddress implements Parcelable {
         if (!isMacAddress(addr)) {
             return TYPE_UNKNOWN;
         }
-        return MacAddress.fromBytes(addr).addressType();
+        return MacAddress.fromBytes(addr).getAddressType();
     }
 
     /**
@@ -211,7 +212,7 @@ public final class MacAddress implements Parcelable {
      *
      * @hide
      */
-    public static byte[] byteAddrFromStringAddr(String addr) {
+    public static @NonNull byte[] byteAddrFromStringAddr(String addr) {
         Preconditions.checkNotNull(addr);
         String[] parts = addr.split(":");
         if (parts.length != ETHER_ADDR_LEN) {
@@ -239,7 +240,7 @@ public final class MacAddress implements Parcelable {
      *
      * @hide
      */
-    public static String stringAddrFromByteAddr(byte[] addr) {
+    public static @NonNull String stringAddrFromByteAddr(byte[] addr) {
         if (!isMacAddress(addr)) {
             return null;
         }
@@ -291,7 +292,7 @@ public final class MacAddress implements Parcelable {
 
     // Internal conversion function equivalent to stringAddrFromByteAddr(byteAddrFromLongAddr(addr))
     // that avoids the allocation of an intermediary byte[].
-    private static String stringAddrFromLongAddr(long addr) {
+    private static @NonNull String stringAddrFromLongAddr(long addr) {
         return String.format("%02x:%02x:%02x:%02x:%02x:%02x",
                 (addr >> 40) & 0xff,
                 (addr >> 32) & 0xff,
@@ -310,7 +311,7 @@ public final class MacAddress implements Parcelable {
      * @return the MacAddress corresponding to the given String representation.
      * @throws IllegalArgumentException if the given String is not a valid representation.
      */
-    public static MacAddress fromString(String addr) {
+    public static @NonNull MacAddress fromString(@NonNull String addr) {
         return new MacAddress(longAddrFromStringAddr(addr));
     }
 
@@ -322,7 +323,7 @@ public final class MacAddress implements Parcelable {
      * @return the MacAddress corresponding to the given byte array representation.
      * @throws IllegalArgumentException if the given byte array is not a valid representation.
      */
-    public static MacAddress fromBytes(byte[] addr) {
+    public static @NonNull MacAddress fromBytes(@NonNull byte[] addr) {
         return new MacAddress(longAddrFromByteAddr(addr));
     }
 
@@ -336,7 +337,7 @@ public final class MacAddress implements Parcelable {
      *
      * @hide
      */
-    public static MacAddress createRandomUnicastAddress() {
+    public static @NonNull MacAddress createRandomUnicastAddress() {
         return createRandomUnicastAddress(BASE_GOOGLE_MAC, new Random());
     }
 
@@ -352,7 +353,7 @@ public final class MacAddress implements Parcelable {
      *
      * @hide
      */
-    public static MacAddress createRandomUnicastAddress(MacAddress base, Random r) {
+    public static @NonNull MacAddress createRandomUnicastAddress(MacAddress base, Random r) {
         long addr = (base.mAddr & OUI_MASK) | (NIC_MASK & r.nextLong());
         addr = addr | LOCALLY_ASSIGNED_MASK;
         addr = addr & ~MULTICAST_MASK;