1.13 Add input validation to ContentProvider insert() method

app/src/main/java/com/example/android/pets/data/PetContract.java

@@ -105,6 +105,17 @@ public static final class PetEntry implements BaseColumns {
         public static final int GENDER_UNKNOWN = 0;
         public static final int GENDER_MALE = 1;
         public static final int GENDER_FEMALE = 2;
+
+        /**
+         * Returns whether or not the given gender is {@link #GENDER_UNKNOWN}, {@link #GENDER_MALE},
+         * or {@link #GENDER_FEMALE}.
+         */
+        public static boolean isValidGender(int gender) {
+            if (gender == GENDER_UNKNOWN || gender == GENDER_MALE || gender == GENDER_FEMALE) {
+                return true;
+            }
+            return false;
+        }
     }
 
 }

app/src/main/java/com/example/android/pets/data/PetProvider.java

@@ -140,6 +140,26 @@ public Uri insert(Uri uri, ContentValues contentValues) {
      * for that specific row in the database.
      */
     private Uri insertPet(Uri uri, ContentValues values) {
+        // Check that the name is not null
+        String name = values.getAsString(PetEntry.COLUMN_PET_NAME);
+        if (name == null) {
+            throw new IllegalArgumentException("Pet requires a name");
+        }
+
+        // Check that the gender is valid
+        Integer gender = values.getAsInteger(PetEntry.COLUMN_PET_GENDER);
+        if (gender == null || !PetEntry.isValidGender(gender)) {
+            throw new IllegalArgumentException("Pet requires valid gender");
+        }
+
+        // If the weight is provided, check that it's greater than or equal to 0 kg
+        Integer weight = values.getAsInteger(PetEntry.COLUMN_PET_WEIGHT);
+        if (weight != null && weight < 0) {
+            throw new IllegalArgumentException("Pet requires valid weight");
+        }
+
+        // No need to check the breed, any value is valid (including null).
+
         // Get writeable database
         SQLiteDatabase database = mDbHelper.getWritableDatabase();