global: Add nullity annotations

Signed-off-by: Eric Kuck <eric@bluelinelabs.com>

app/src/main/java/com/wireguard/config/Interface.java

@@ -10,6 +10,7 @@ import android.databinding.BaseObservable;
 import android.databinding.Bindable;
 import android.os.Parcel;
 import android.os.Parcelable;
+import android.support.annotation.Nullable;
 
 import com.wireguard.android.BR;
 import com.wireguard.crypto.Keypair;
@@ -27,7 +28,7 @@ public class Interface {
     private final List<InetNetwork> addressList;
     private final List<InetAddress> dnsList;
     private final List<String> excludedApplications;
-    private Keypair keypair;
+    @Nullable private Keypair keypair;
     private int listenPort;
     private int mtu;
 
@@ -37,7 +38,7 @@ public class Interface {
         excludedApplications = new ArrayList<>();
     }
 
-    private void addAddresses(final String[] addresses) {
+    private void addAddresses(@Nullable final String[] addresses) {
         if (addresses != null && addresses.length > 0) {
             for (final String addr : addresses) {
                 if (addr.isEmpty())
@@ -47,7 +48,7 @@ public class Interface {
         }
     }
 
-    private void addDnses(final String[] dnses) {
+    private void addDnses(@Nullable final String[] dnses) {
         if (dnses != null && dnses.length > 0) {
             for (final String dns : dnses) {
                 dnsList.add(InetAddresses.parse(dns));
@@ -55,12 +56,13 @@ public class Interface {
         }
     }
 
-    private void addExcludedApplications(final String[] applications) {
+    private void addExcludedApplications(@Nullable final String[] applications) {
         if (applications != null && applications.length > 0) {
             excludedApplications.addAll(Arrays.asList(applications));
         }
     }
 
+    @Nullable
     private String getAddressString() {
         if (addressList.isEmpty())
             return null;
@@ -71,6 +73,7 @@ public class Interface {
         return addressList.toArray(new InetNetwork[addressList.size()]);
     }
 
+    @Nullable
     private String getDnsString() {
         if (dnsList.isEmpty())
             return null;
@@ -88,6 +91,7 @@ public class Interface {
         return dnsList.toArray(new InetAddress[dnsList.size()]);
     }
 
+    @Nullable
     private String getExcludedApplicationsString() {
         if (excludedApplications.isEmpty())
             return null;
@@ -102,6 +106,7 @@ public class Interface {
         return listenPort;
     }
 
+    @Nullable
     private String getListenPortString() {
         if (listenPort == 0)
             return null;
@@ -112,18 +117,21 @@ public class Interface {
         return mtu;
     }
 
+    @Nullable
     private String getMtuString() {
         if (mtu == 0)
             return null;
         return Integer.toString(mtu);
     }
 
+    @Nullable
     public String getPrivateKey() {
         if (keypair == null)
             return null;
         return keypair.getPrivateKey();
     }
 
+    @Nullable
     public String getPublicKey() {
         if (keypair == null)
             return null;
@@ -156,17 +164,17 @@ public class Interface {
         }
     }
 
-    private void setAddressString(final String addressString) {
+    private void setAddressString(@Nullable final String addressString) {
         addressList.clear();
         addAddresses(Attribute.stringToList(addressString));
     }
 
-    private void setDnsString(final String dnsString) {
+    private void setDnsString(@Nullable final String dnsString) {
         dnsList.clear();
         addDnses(Attribute.stringToList(dnsString));
     }
 
-    private void setExcludedApplicationsString(final String applicationsString) {
+    private void setExcludedApplicationsString(@Nullable final String applicationsString) {
         excludedApplications.clear();
         addExcludedApplications(Attribute.stringToList(applicationsString));
     }
@@ -175,7 +183,7 @@ public class Interface {
         this.listenPort = listenPort;
     }
 
-    private void setListenPortString(final String port) {
+    private void setListenPortString(@Nullable final String port) {
         if (port != null && !port.isEmpty())
             setListenPort(Integer.parseInt(port, 10));
         else
@@ -186,14 +194,14 @@ public class Interface {
         this.mtu = mtu;
     }
 
-    private void setMtuString(final String mtu) {
+    private void setMtuString(@Nullable final String mtu) {
         if (mtu != null && !mtu.isEmpty())
             setMtu(Integer.parseInt(mtu, 10));
         else
             setMtu(0);
     }
 
-    private void setPrivateKey(String privateKey) {
+    private void setPrivateKey(@Nullable String privateKey) {
         if (privateKey != null && privateKey.isEmpty())
             privateKey = null;
         keypair = privateKey == null ? null : new Keypair(privateKey);
@@ -229,15 +237,15 @@ public class Interface {
                 return new Observable[size];
             }
         };
-        private String addresses;
-        private String dnses;
-        private String excludedApplications;
-        private String listenPort;
-        private String mtu;
-        private String privateKey;
-        private String publicKey;
+        @Nullable private String addresses;
+        @Nullable private String dnses;
+        @Nullable private String excludedApplications;
+        @Nullable private String listenPort;
+        @Nullable private String mtu;
+        @Nullable private String privateKey;
+        @Nullable private String publicKey;
 
-        public Observable(final Interface parent) {
+        public Observable(@Nullable final Interface parent) {
             if (parent != null)
                 loadData(parent);
         }
@@ -276,16 +284,19 @@ public class Interface {
             notifyPropertyChanged(BR.publicKey);
         }
 
+        @Nullable
         @Bindable
         public String getAddresses() {
             return addresses;
         }
 
+        @Nullable
         @Bindable
         public String getDnses() {
             return dnses;
         }
 
+        @Nullable
         @Bindable
         public String getExcludedApplications() {
             return excludedApplications;
@@ -296,21 +307,25 @@ public class Interface {
             return Attribute.stringToList(excludedApplications).length;
         }
 
+        @Nullable
         @Bindable
         public String getListenPort() {
             return listenPort;
         }
 
+        @Nullable
         @Bindable
         public String getMtu() {
             return mtu;
         }
 
+        @Nullable
         @Bindable
         public String getPrivateKey() {
             return privateKey;
         }
 
+        @Nullable
         @Bindable
         public String getPublicKey() {
             return publicKey;