Added Nullness Checker annotation

ImageSteganographyLibrary/build.gradle

@@ -3,8 +3,6 @@ apply plugin: 'com.android.library'
 android {
     compileSdkVersion 26
 
-
-
     defaultConfig {
         minSdkVersion 19
         targetSdkVersion 26
@@ -13,30 +11,60 @@ android {
 
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
 
-
-
     }
 
     buildTypes {
         release {
             minifyEnabled false
             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
         }
+
+        checkTypes {
+            javaCompileOptions.annotationProcessorOptions.
+                    classNames.add("org.checkerframework.checker.nullness.NullnessChecker")
+            // You can pass options like so:
+            // javaCompileOptions.annotationProcessorOptions.arguments.put("warns", "")
+        }
+    }
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
     }
 
 }
 
+configurations {
+    checkerFrameworkAnnotatedJDK {
+        description = 'a copy of JDK classes with Checker Framework type qualifers inserted'
+    }
+}
+
+
 configurations.all {
     resolutionStrategy {
         force 'com.android.support:support-annotations:23.1.1'
     }
 }
 
 dependencies {
-    implementation fileTree(dir: 'libs', include: ['*.jar'])
-
+    implementation fileTree(include: ['*.jar'], dir: 'libs')
     implementation 'com.android.support:appcompat-v7:26.1.0'
     testImplementation 'junit:junit:4.12'
     androidTestImplementation 'com.android.support.test:runner:1.0.2'
     androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
+    ext.checkerFrameworkVersion = '2.7.0'
+    implementation "org.checkerframework:checker-qual:${checkerFrameworkVersion}"
+    annotationProcessor "org.checkerframework:checker:${checkerFrameworkVersion}"
+    checkerFrameworkAnnotatedJDK "org.checkerframework:jdk8:${checkerFrameworkVersion}"
 }
+
+gradle.projectsEvaluated {
+    tasks.withType(JavaCompile).all { compile ->
+        if (compile.name.contains("checkTypes")) {
+            compile.options.compilerArgs += [
+                    "-Xbootclasspath/p:${configurations.checkerFrameworkAnnotatedJDK.asPath}"
+            ]
+        }
+    }
+}

ImageSteganographyLibrary/src/main/java/com/ayush/imagesteganographylibrary/Text/AsyncTaskCallback/TextDecodingCallback.java

@@ -2,6 +2,8 @@
 
 import com.ayush.imagesteganographylibrary.Text.ImageSteganography;
 
+import org.checkerframework.checker.nullness.qual.RequiresNonNull;
+
 /**
  * This the callback interface for TextDecoding AsyncTask.
  */
@@ -10,6 +12,7 @@ public interface TextDecodingCallback {
 
     void onStartTextEncoding();
 
+//    @RequiresNonNull("#1")
     void onCompleteTextEncoding(ImageSteganography result);
 
 }

ImageSteganographyLibrary/src/main/java/com/ayush/imagesteganographylibrary/Text/AsyncTaskCallback/TextEncodingCallback.java

@@ -2,6 +2,8 @@
 
 import com.ayush.imagesteganographylibrary.Text.ImageSteganography;
 
+import org.checkerframework.checker.nullness.qual.RequiresNonNull;
+
 /**
  * This the callback interface for TextEncoding AsyncTask.
  */
@@ -10,6 +12,7 @@ public interface TextEncodingCallback {
 
     void onStartTextEncoding();
 
+//    @RequiresNonNull("#1")
     void onCompleteTextEncoding(ImageSteganography result);
 
 }

ImageSteganographyLibrary/src/main/java/com/ayush/imagesteganographylibrary/Text/EncodeDecode.java

@@ -2,10 +2,13 @@
 
 import android.graphics.Bitmap;
 import android.graphics.Color;
+import android.support.annotation.Nullable;
 import android.util.Log;
 
 import com.ayush.imagesteganographylibrary.Utils.Utility;
 
+import org.checkerframework.checker.nullness.qual.RequiresNonNull;
+
 import java.nio.charset.Charset;
 import java.util.ArrayList;
 import java.util.List;
@@ -32,8 +35,9 @@ class EncodeDecode {
      * @parameter : progressHandler {A handler interface, for the progress bar}
      */
 
+//    @RequiresNonNull({"#1", "#4"})
     private static byte[] encodeMessage(int[] integer_pixel_array, int image_columns, int image_rows,
-                                        MessageEncodingStatus messageEncodingStatus, ProgressHandler progressHandler) {
+                                        MessageEncodingStatus messageEncodingStatus, @Nullable ProgressHandler progressHandler) {
 
         //denotes RGB channels
         int channels = 3;
@@ -105,8 +109,9 @@ private static byte[] encodeMessage(int[] integer_pixel_array, int image_columns
      * @parameter : encrypted_message {string}
      * @parameter : progressHandler {Progress bar handler}
      */
+//    @RequiresNonNull({"#1"})
     public static List<Bitmap> encodeMessage(List<Bitmap> splitted_images,
-                                             String encrypted_message, ProgressHandler progressHandler) {
+                                             String encrypted_message, @Nullable ProgressHandler progressHandler) {
 
         //Making result method
 
@@ -191,6 +196,7 @@ public static List<Bitmap> encodeMessage(List<Bitmap> splitted_images,
      * @parameter : image_rows {Image height}
      * @parameter : messageDecodingStatus {object}
      */
+//    @RequiresNonNull({"#1", "#4"})
     private static void decodeMessage(byte[] byte_pixel_array, int image_columns,
                                       int image_rows, MessageDecodingStatus messageDecodingStatus) {
 
@@ -231,7 +237,6 @@ private static void decodeMessage(byte[] byte_pixel_array, int image_columns,
 
                     String stra = new String(temp, Charset.forName("ISO-8859-1"));
 
-
                     messageDecodingStatus.setMessage(stra.substring(0, stra.length() - 1));
                     //end fixing
 
@@ -279,6 +284,7 @@ private static void decodeMessage(byte[] byte_pixel_array, int image_columns,
      * @parameter : encodedImages {list of encode chunk images}
      */
 
+//    @RequiresNonNull("#1")
     public static String decodeMessage(List<Bitmap> encodedImages) {
 
         //Creating object
@@ -309,7 +315,7 @@ public static String decodeMessage(List<Bitmap> encodedImages) {
      * @return : The number of pixel {integer}
      * @parameter : message {Message to encode}
      */
-    public static int numberOfPixelForMessage(String message) {
+    public static int numberOfPixelForMessage(@Nullable String message) {
         int result = -1;
         if (message != null) {
             message += END_MESSAGE_COSTANT;
@@ -323,8 +329,10 @@ public static int numberOfPixelForMessage(String message) {
     //Progress handler class
     public interface ProgressHandler {
 
+//        @RequiresNonNull("#1")
         void setTotal(int tot);
 
+        //        @RequiresNonNull("#1")
         void increment(int inc);
 
         void finished();
@@ -352,6 +360,7 @@ String getMessage() {
             return message;
         }
 
+//        @RequiresNonNull("#1")
         void setMessage(String message) {
             this.message = message;
         }
@@ -365,6 +374,7 @@ private static class MessageEncodingStatus {
         private byte[] byteArrayMessage;
         private String message;
 
+//        @RequiresNonNull({"#1", "#2"})
         MessageEncodingStatus(byte[] byteArrayMessage, String message) {
             this.messageEncoded = false;
             this.currentMessageIndex = 0;
@@ -380,6 +390,7 @@ public String getMessage() {
             return message;
         }
 
+//        @RequiresNonNull("#1")
         public void setMessage(String message) {
             this.message = message;
         }
@@ -396,6 +407,7 @@ int getCurrentMessageIndex() {
             return currentMessageIndex;
         }
 
+//        @RequiresNonNull("#1")
         public void setCurrentMessageIndex(int currentMessageIndex) {
             this.currentMessageIndex = currentMessageIndex;
         }
@@ -404,6 +416,7 @@ byte[] getByteArrayMessage() {
             return byteArrayMessage;
         }
 
+//        @RequiresNonNull("#1")
         public void setByteArrayMessage(byte[] byteArrayMessage) {
             this.byteArrayMessage = byteArrayMessage;
         }

ImageSteganographyLibrary/src/main/java/com/ayush/imagesteganographylibrary/Text/ImageSteganography.java

@@ -6,6 +6,8 @@
 import com.ayush.imagesteganographylibrary.Utils.Crypto;
 import com.ayush.imagesteganographylibrary.Utils.Utility;
 
+import org.checkerframework.checker.nullness.qual.RequiresNonNull;
+
 /**
  * This main class of the text steganography
  */
@@ -36,6 +38,7 @@ public ImageSteganography() {
         this.encrypted_zip = new byte[0];
     }
 
+//    @RequiresNonNull({"#1", "#2", "#3"})
     public ImageSteganography(String message, String secret_key, Bitmap image) {
 
         this.message = message;
@@ -58,6 +61,7 @@ public ImageSteganography(String message, String secret_key, Bitmap image) {
 
     }
 
+//    @RequiresNonNull({"#1", "#2"})
     public ImageSteganography(String secret_key, Bitmap image) {
         this.secret_key = convertKeyTo128bit(secret_key);
         this.image = image;
@@ -110,6 +114,7 @@ public static String decryptMessage(String message, String secret_key) {
         return decrypted_message;
     }
 
+//    @RequiresNonNull("#1")
     private static String convertKeyTo128bit(String secret_key) {
 
         StringBuilder result = new StringBuilder(secret_key);
@@ -131,6 +136,7 @@ public Bitmap getEncoded_image() {
         return encoded_image;
     }
 
+//    @RequiresNonNull("#1")
     public void setEncoded_image(Bitmap encoded_image) {
         this.encoded_image = encoded_image;
     }
@@ -139,6 +145,7 @@ public String getMessage() {
         return message;
     }
 
+//    @RequiresNonNull("#1")
     public void setMessage(String message) {
         this.message = message;
     }
@@ -147,6 +154,7 @@ public String getSecret_key() {
         return secret_key;
     }
 
+//    @RequiresNonNull("#1")
     public void setSecret_key(String secret_key) {
         this.secret_key = secret_key;
     }
@@ -155,6 +163,7 @@ public byte[] getEncrypted_zip() {
         return encrypted_zip;
     }
 
+//    @RequiresNonNull("#1")
     public void setEncrypted_zip(byte[] encrypted_zip) {
         this.encrypted_zip = encrypted_zip;
     }
@@ -163,6 +172,7 @@ public String getEncrypted_message() {
         return encrypted_message;
     }
 
+//    @RequiresNonNull("#1")
     public void setEncrypted_message(String encrypted_message) {
         this.encrypted_message = encrypted_message;
     }
@@ -171,6 +181,7 @@ public Bitmap getImage() {
         return image;
     }
 
+//    @RequiresNonNull("#1")
     public void setImage(Bitmap image) {
         this.image = image;
     }

ImageSteganographyLibrary/src/main/java/com/ayush/imagesteganographylibrary/Text/TextDecoding.java

@@ -9,6 +9,9 @@
 import com.ayush.imagesteganographylibrary.Text.AsyncTaskCallback.TextDecodingCallback;
 import com.ayush.imagesteganographylibrary.Utils.Utility;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+import org.checkerframework.checker.nullness.qual.RequiresNonNull;
+
 import java.util.List;
 
 /**
@@ -23,17 +26,21 @@ public class TextDecoding extends AsyncTask<ImageSteganography, Void, ImageStega
     private final ImageSteganography result;
     //Callback interface for AsyncTask
     private final TextDecodingCallback textDecodingCallback;
-    private ProgressDialog progressDialog;
+    private @Nullable ProgressDialog progressDialog;
 
-    public TextDecoding(Activity activity, TextDecodingCallback textDecodingCallback) {
+//    @RequiresNonNull("#2")
+    public TextDecoding(@Nullable Activity activity, TextDecodingCallback textDecodingCallback) {
         super();
-        this.progressDialog = new ProgressDialog(activity);
+        if (activity != null) {
+            this.progressDialog = new ProgressDialog(activity);
+        }
         this.textDecodingCallback = textDecodingCallback;
         //making result object
         this.result = new ImageSteganography();
     }
 
     //setting progress dialog if wanted
+//    @RequiresNonNull("#1")
     public void setProgressDialog(ProgressDialog progressDialog) {
         this.progressDialog = progressDialog;
     }