Camera: Polish ExtensionService docs and APIs

Improve various extension related system APIs including:
- Missing java docs
- Missing doc links
- Incorrect or missing annotations
- Interface names

Bug: 322520569
Test: make docs

Change-Id: I4fc25b419315e92c1df80479c35b572c412f09b4

9 files changed, 253 insertions, 129 deletions

diff --git a/core/api/system-current.txt b/core/api/system-current.txt
index d0fdf694cad7..521d00f0f148 100644
--- a/core/api/system-current.txt
+++ b/core/api/system-current.txt
@@ -4583,7 +4583,7 @@ package android.hardware.camera2 {
 package android.hardware.camera2.extension {
 
   @FlaggedApi("com.android.internal.camera.flags.concert_mode") public abstract class AdvancedExtender {
-    ctor @FlaggedApi("com.android.internal.camera.flags.concert_mode") protected AdvancedExtender(@NonNull android.hardware.camera2.CameraManager);
+    ctor @FlaggedApi("com.android.internal.camera.flags.concert_mode") public AdvancedExtender(@NonNull android.hardware.camera2.CameraManager);
     method @FlaggedApi("com.android.internal.camera.flags.concert_mode") @NonNull public abstract java.util.List<android.hardware.camera2.CaptureRequest.Key> getAvailableCaptureRequestKeys(@NonNull String);
     method @FlaggedApi("com.android.internal.camera.flags.concert_mode") @NonNull public abstract java.util.List<android.hardware.camera2.CaptureResult.Key> getAvailableCaptureResultKeys(@NonNull String);
     method @FlaggedApi("com.android.internal.camera.flags.camera_extensions_characteristics_get") @NonNull public abstract java.util.List<android.util.Pair<android.hardware.camera2.CameraCharacteristics.Key,java.lang.Object>> getAvailableCharacteristicsKeyValues();
@@ -4591,23 +4591,23 @@ package android.hardware.camera2.extension {
     method @FlaggedApi("com.android.internal.camera.flags.concert_mode") @NonNull public abstract android.hardware.camera2.extension.SessionProcessor getSessionProcessor();
     method @FlaggedApi("com.android.internal.camera.flags.concert_mode") @NonNull public abstract java.util.Map<java.lang.Integer,java.util.List<android.util.Size>> getSupportedCaptureOutputResolutions(@NonNull String);
     method @FlaggedApi("com.android.internal.camera.flags.concert_mode") @NonNull public abstract java.util.Map<java.lang.Integer,java.util.List<android.util.Size>> getSupportedPreviewOutputResolutions(@NonNull String);
-    method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public abstract void init(@NonNull String, @NonNull android.hardware.camera2.extension.CharacteristicsMap);
+    method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public abstract void initialize(@NonNull String, @NonNull android.hardware.camera2.extension.CharacteristicsMap);
     method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public abstract boolean isExtensionAvailable(@NonNull String, @NonNull android.hardware.camera2.extension.CharacteristicsMap);
   }
 
   @FlaggedApi("com.android.internal.camera.flags.concert_mode") public abstract class CameraExtensionService extends android.app.Service {
     ctor @FlaggedApi("com.android.internal.camera.flags.concert_mode") protected CameraExtensionService();
-    method @FlaggedApi("com.android.internal.camera.flags.concert_mode") @NonNull public android.os.IBinder onBind(@Nullable android.content.Intent);
+    method @FlaggedApi("com.android.internal.camera.flags.concert_mode") @NonNull public final android.os.IBinder onBind(@Nullable android.content.Intent);
     method @FlaggedApi("com.android.internal.camera.flags.concert_mode") @NonNull public abstract android.hardware.camera2.extension.AdvancedExtender onInitializeAdvancedExtension(int);
     method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public abstract boolean onRegisterClient(@NonNull android.os.IBinder);
     method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public abstract void onUnregisterClient(@NonNull android.os.IBinder);
   }
 
   @FlaggedApi("com.android.internal.camera.flags.concert_mode") public final class CameraOutputSurface {
-    ctor @FlaggedApi("com.android.internal.camera.flags.concert_mode") public CameraOutputSurface(@NonNull android.view.Surface, @Nullable android.util.Size);
+    ctor @FlaggedApi("com.android.internal.camera.flags.concert_mode") public CameraOutputSurface(@NonNull android.view.Surface, @NonNull android.util.Size);
     method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public int getImageFormat();
-    method @FlaggedApi("com.android.internal.camera.flags.concert_mode") @Nullable public android.util.Size getSize();
-    method @FlaggedApi("com.android.internal.camera.flags.concert_mode") @Nullable public android.view.Surface getSurface();
+    method @FlaggedApi("com.android.internal.camera.flags.concert_mode") @NonNull public android.util.Size getSize();
+    method @FlaggedApi("com.android.internal.camera.flags.concert_mode") @NonNull public android.view.Surface getSurface();
   }
 
   @FlaggedApi("com.android.internal.camera.flags.concert_mode") public class CharacteristicsMap {
@@ -4625,10 +4625,10 @@ package android.hardware.camera2.extension {
 
   @FlaggedApi("com.android.internal.camera.flags.concert_mode") public final class RequestProcessor {
     method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public void abortCaptures();
-    method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public int setRepeating(@NonNull android.hardware.camera2.extension.RequestProcessor.Request, @Nullable java.util.concurrent.Executor, @NonNull android.hardware.camera2.extension.RequestProcessor.RequestCallback);
+    method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public int setRepeating(@NonNull android.hardware.camera2.extension.RequestProcessor.Request, @NonNull java.util.concurrent.Executor, @NonNull android.hardware.camera2.extension.RequestProcessor.RequestCallback) throws android.hardware.camera2.CameraAccessException;
     method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public void stopRepeating();
-    method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public int submit(@NonNull android.hardware.camera2.extension.RequestProcessor.Request, @Nullable java.util.concurrent.Executor, @NonNull android.hardware.camera2.extension.RequestProcessor.RequestCallback);
-    method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public int submitBurst(@NonNull java.util.List<android.hardware.camera2.extension.RequestProcessor.Request>, @Nullable java.util.concurrent.Executor, @NonNull android.hardware.camera2.extension.RequestProcessor.RequestCallback);
+    method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public int submit(@NonNull android.hardware.camera2.extension.RequestProcessor.Request, @NonNull java.util.concurrent.Executor, @NonNull android.hardware.camera2.extension.RequestProcessor.RequestCallback) throws android.hardware.camera2.CameraAccessException;
+    method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public int submitBurst(@NonNull java.util.List<android.hardware.camera2.extension.RequestProcessor.Request>, @NonNull java.util.concurrent.Executor, @NonNull android.hardware.camera2.extension.RequestProcessor.RequestCallback) throws android.hardware.camera2.CameraAccessException;
   }
 
   @FlaggedApi("com.android.internal.camera.flags.concert_mode") public static final class RequestProcessor.Request {
@@ -4647,15 +4647,15 @@ package android.hardware.camera2.extension {
   }
 
   @FlaggedApi("com.android.internal.camera.flags.concert_mode") public abstract class SessionProcessor {
-    ctor @FlaggedApi("com.android.internal.camera.flags.concert_mode") protected SessionProcessor();
+    ctor @FlaggedApi("com.android.internal.camera.flags.concert_mode") public SessionProcessor();
     method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public abstract void deInitSession(@NonNull android.os.IBinder);
     method @FlaggedApi("com.android.internal.camera.flags.concert_mode") @NonNull public abstract android.hardware.camera2.extension.ExtensionConfiguration initSession(@NonNull android.os.IBinder, @NonNull String, @NonNull android.hardware.camera2.extension.CharacteristicsMap, @NonNull android.hardware.camera2.extension.CameraOutputSurface, @NonNull android.hardware.camera2.extension.CameraOutputSurface);
     method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public abstract void onCaptureSessionEnd();
     method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public abstract void onCaptureSessionStart(@NonNull android.hardware.camera2.extension.RequestProcessor, @NonNull String);
     method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public abstract void setParameters(@NonNull android.hardware.camera2.CaptureRequest);
-    method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public abstract int startCapture(@Nullable java.util.concurrent.Executor, @NonNull android.hardware.camera2.extension.SessionProcessor.CaptureCallback);
-    method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public abstract int startRepeating(@Nullable java.util.concurrent.Executor, @NonNull android.hardware.camera2.extension.SessionProcessor.CaptureCallback);
-    method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public abstract int startTrigger(@NonNull android.hardware.camera2.CaptureRequest, @Nullable java.util.concurrent.Executor, @NonNull android.hardware.camera2.extension.SessionProcessor.CaptureCallback);
+    method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public abstract int startMultiFrameCapture(@NonNull java.util.concurrent.Executor, @NonNull android.hardware.camera2.extension.SessionProcessor.CaptureCallback);
+    method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public abstract int startRepeating(@NonNull java.util.concurrent.Executor, @NonNull android.hardware.camera2.extension.SessionProcessor.CaptureCallback);
+    method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public abstract int startTrigger(@NonNull android.hardware.camera2.CaptureRequest, @NonNull java.util.concurrent.Executor, @NonNull android.hardware.camera2.extension.SessionProcessor.CaptureCallback);
     method @FlaggedApi("com.android.internal.camera.flags.concert_mode") public abstract void stopRepeating();
   }
 
diff --git a/core/java/android/hardware/camera2/extension/AdvancedExtender.java b/core/java/android/hardware/camera2/extension/AdvancedExtender.java
index 665357726ebf..4895f38d7328 100644
--- a/core/java/android/hardware/camera2/extension/AdvancedExtender.java
+++ b/core/java/android/hardware/camera2/extension/AdvancedExtender.java
@@ -43,8 +43,9 @@ import java.util.Map;
  *
  * <p>This advanced contract empowers implementations to gain access to
  * more Camera2 capability. This includes: (1) Add custom surfaces with
- * specific formats like YUV, RAW, RAW_DEPTH. (2) Access to
- * the capture request callbacks as well as all the images retrieved of
+ * specific formats like {@link android.graphics.ImageFormat#YUV_420_888},
+ * {@link android.graphics.ImageFormat#RAW10}, {@link android.graphics.ImageFormat#RAW_DEPTH10}.
+ * (2) Access to the capture request callbacks as well as all the images retrieved of
  * various image formats. (3)
  * Able to triggers single or repeating request with the capabilities to
  * specify target surfaces, template id and parameters.
@@ -60,8 +61,14 @@ public abstract class AdvancedExtender {
     private CameraUsageTracker mCameraUsageTracker;
     private static final String TAG = "AdvancedExtender";
 
+
+    /**
+     * Initialize a camera extension advanced extender instance.
+     *
+     * @param cameraManager the system camera manager
+     */
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
-    protected AdvancedExtender(@NonNull CameraManager cameraManager) {
+    public AdvancedExtender(@NonNull CameraManager cameraManager) {
         mCameraManager = cameraManager;
         try {
             String [] cameraIds = mCameraManager.getCameraIdListNoLazy();
@@ -87,6 +94,14 @@ public abstract class AdvancedExtender {
         mCameraUsageTracker = tracker;
     }
 
+    /**
+     * Returns the camera metadata vendor id, that can be used to
+     * configure and enable vendor tag support for a particular
+     * camera metadata buffer.
+     *
+     * @param cameraId           The camera2 id string of the camera.
+     * @return the camera metadata vendor Id associated with the given camera
+     */
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
     public long getMetadataVendorId(@NonNull String cameraId) {
         long vendorId = mMetadataVendorIdMap.containsKey(cameraId) ?
@@ -131,12 +146,15 @@ public abstract class AdvancedExtender {
      *                           CameraCharacteristics.
      */
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
-    public abstract void init(@NonNull String cameraId, @NonNull CharacteristicsMap map);
+    public abstract void initialize(@NonNull String cameraId, @NonNull CharacteristicsMap map);
 
     /**
      * Returns supported output format/size map for preview. The format
-     * could be PRIVATE or YUV_420_888. Implementations must support
-     * PRIVATE format at least.
+     * could be {@link android.graphics.ImageFormat#PRIVATE} or
+     * {@link android.graphics.ImageFormat#YUV_420_888}. Implementations must support
+     * {@link android.graphics.ImageFormat#PRIVATE} format at least.
+     * An example of how the map is parsed can be found in
+     * {@link #initializeParcelable(Map)}
      *
      * <p>The preview surface format in the CameraCaptureSession may not
      * be identical to the supported preview output format returned here.
@@ -149,11 +167,16 @@ public abstract class AdvancedExtender {
 
     /**
      * Returns supported output format/size map for image capture. OEM is
-     * required to support both JPEG and YUV_420_888 format output.
+     * required to support both {@link android.graphics.ImageFormat#JPEG} and
+     * {@link android.graphics.ImageFormat#YUV_420_888} format output.
+     * An example of how the map is parsed can be found in
+     * {@link #initializeParcelable(Map)}
      *
      * <p>The surface created with this supported
      * format/size could be either added in CameraCaptureSession with HAL
-     * processing OR it  configures intermediate surfaces(YUV/RAW..) and
+     * processing OR it  configures intermediate surfaces(
+     * {@link android.graphics.ImageFormat#YUV_420_888}/
+     * {@link android.graphics.ImageFormat#RAW10}..) and
      * writes the output to the output surface.
      * @param cameraId           The camera2 id string of the camera.
      */
@@ -256,7 +279,7 @@ public abstract class AdvancedExtender {
 
         @Override
         public void init(String cameraId, Map<String, CameraMetadataNative> charsMapNative) {
-            AdvancedExtender.this.init(cameraId, new CharacteristicsMap(charsMapNative));
+            AdvancedExtender.this.initialize(cameraId, new CharacteristicsMap(charsMapNative));
         }
 
         @Override
diff --git a/core/java/android/hardware/camera2/extension/CameraExtensionService.java b/core/java/android/hardware/camera2/extension/CameraExtensionService.java
index fa0d14a3f05a..01698d54150c 100644
--- a/core/java/android/hardware/camera2/extension/CameraExtensionService.java
+++ b/core/java/android/hardware/camera2/extension/CameraExtensionService.java
@@ -23,6 +23,7 @@ import android.annotation.SystemApi;
 import android.app.AppOpsManager;
 import android.app.Service;
 import android.content.Intent;
+import android.hardware.camera2.CameraExtensionCharacteristics.Extension;
 import android.os.IBinder;
 import android.os.RemoteException;
 import android.util.Log;
@@ -92,7 +93,7 @@ public abstract class CameraExtensionService extends Service {
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
     @Override
     @NonNull
-    public IBinder onBind(@Nullable Intent intent) {
+    public final IBinder onBind(@Nullable Intent intent) {
         if (mCameraUsageTracker == null) {
             mCameraUsageTracker = new CameraTracker();
         }
@@ -153,21 +154,21 @@ public abstract class CameraExtensionService extends Service {
         }
 
         @Override
-        public IPreviewExtenderImpl initializePreviewExtension(int extensionType)
+        public IPreviewExtenderImpl initializePreviewExtension(@Extension int extensionType)
                 throws RemoteException {
             // Basic Extension API is not supported
             return null;
         }
 
         @Override
-        public IImageCaptureExtenderImpl initializeImageExtension(int extensionType)
+        public IImageCaptureExtenderImpl initializeImageExtension(@Extension int extensionType)
                 throws RemoteException {
             // Basic Extension API is not supported
             return null;
         }
 
         @Override
-        public IAdvancedExtenderImpl initializeAdvancedExtension(int extensionType)
+        public IAdvancedExtenderImpl initializeAdvancedExtension(@Extension int extensionType)
                 throws RemoteException {
             AdvancedExtender extender =  CameraExtensionService.this.onInitializeAdvancedExtension(
                     extensionType);
@@ -205,5 +206,5 @@ public abstract class CameraExtensionService extends Service {
      */
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
     @NonNull
-    public abstract AdvancedExtender onInitializeAdvancedExtension(int extensionType);
+    public abstract AdvancedExtender onInitializeAdvancedExtension(@Extension int extensionType);
 }
diff --git a/core/java/android/hardware/camera2/extension/CameraOutputSurface.java b/core/java/android/hardware/camera2/extension/CameraOutputSurface.java
index f98ebee5d7c7..b4fe7fe1f0d1 100644
--- a/core/java/android/hardware/camera2/extension/CameraOutputSurface.java
+++ b/core/java/android/hardware/camera2/extension/CameraOutputSurface.java
@@ -18,8 +18,8 @@ package android.hardware.camera2.extension;
 
 import android.annotation.FlaggedApi;
 import android.annotation.NonNull;
-import android.annotation.Nullable;
 import android.annotation.SystemApi;
+import android.graphics.ImageFormat;
 import android.hardware.camera2.utils.SurfaceUtils;
 import android.util.Size;
 import android.view.Surface;
@@ -28,6 +28,14 @@ import com.android.internal.camera.flags.Flags;
 
 
 /**
+ * Helper method used to describe a single camera output
+ * {@link Surface}.
+ *
+ * <p>Instances of this class can be used as arguments when
+ * initializing {@link ExtensionOutputConfiguration}.</p>
+ *
+ * @see ExtensionConfiguration
+ * @see ExtensionOutputConfiguration
  * @hide
  */
 @SystemApi
@@ -40,27 +48,39 @@ public final class CameraOutputSurface {
        mOutputSurface = surface;
     }
 
+    /**
+     * Initialize a camera output surface instance
+     *
+     * @param surface      Output {@link Surface} to be
+     *                     configured as camera output
+     * @param size         Requested size of the camera
+     *                     output
+     */
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
     public CameraOutputSurface(@NonNull Surface surface,
-            @Nullable Size size ) {
+            @NonNull Size size) {
         mOutputSurface = new OutputSurface();
         mOutputSurface.surface = surface;
         mOutputSurface.imageFormat = SurfaceUtils.getSurfaceFormat(surface);
-        if (size != null) {
-            mOutputSurface.size = new android.hardware.camera2.extension.Size();
-            mOutputSurface.size.width = size.getWidth();
-            mOutputSurface.size.height = size.getHeight();
-        }
+        mOutputSurface.size = new android.hardware.camera2.extension.Size();
+        mOutputSurface.size.width = size.getWidth();
+        mOutputSurface.size.height = size.getHeight();
     }
 
+    /**
+     * Return the current output {@link Surface}
+     */
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
-    @Nullable
+    @NonNull
     public Surface getSurface() {
         return mOutputSurface.surface;
     }
 
+    /**
+     * Return the current requested output size
+     */
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
-    @Nullable
+    @NonNull
     public android.util.Size getSize() {
         if (mOutputSurface.size != null) {
             return new Size(mOutputSurface.size.width, mOutputSurface.size.height);
@@ -68,8 +88,11 @@ public final class CameraOutputSurface {
         return null;
     }
 
+    /**
+     * Return the current surface output {@link android.graphics.ImageFormat}
+     */
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
-    public int getImageFormat() {
+    public @ImageFormat.Format int getImageFormat() {
         return mOutputSurface.imageFormat;
     }
 }
diff --git a/core/java/android/hardware/camera2/extension/CharacteristicsMap.java b/core/java/android/hardware/camera2/extension/CharacteristicsMap.java
index af83595babef..495abc8100ae 100644
--- a/core/java/android/hardware/camera2/extension/CharacteristicsMap.java
+++ b/core/java/android/hardware/camera2/extension/CharacteristicsMap.java
@@ -30,12 +30,22 @@ import java.util.Map;
 import java.util.Set;
 
 /**
+ * Helper class used to forward the current
+ * system camera characteristics information.
+ *
  * @hide
  */
 @SystemApi
 @FlaggedApi(Flags.FLAG_CONCERT_MODE)
 public class CharacteristicsMap {
     private final HashMap<String, CameraCharacteristics> mCharMap;
+
+    /**
+     * Initialize a camera characteristics map instance
+     *
+     * @param charsMap       Maps camera ids to respective
+     *                       {@link CameraCharacteristics}
+     */
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
     CharacteristicsMap(@NonNull Map<String, CameraMetadataNative> charsMap) {
         mCharMap = new HashMap<>();
@@ -44,12 +54,26 @@ public class CharacteristicsMap {
         }
     }
 
+    /**
+     * Return the set of camera ids stored in the characteristics map
+     *
+     * @return Set of the camera ids stored in the map
+     */
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
     @NonNull
     public Set<String> getCameraIds() {
         return mCharMap.keySet();
     }
 
+    /**
+     * Return the corresponding {@link CameraCharacteristics} given
+     * a valid camera id
+     *
+     * @param cameraId Camera device id
+     *
+     * @return Valid {@link CameraCharacteristics} instance of null
+     *         in case the camera id is not part of the map
+     */
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
     @Nullable
     public CameraCharacteristics get(@NonNull String cameraId) {
diff --git a/core/java/android/hardware/camera2/extension/ExtensionConfiguration.java b/core/java/android/hardware/camera2/extension/ExtensionConfiguration.java
index 2d9ab765d1e0..96c88e660e10 100644
--- a/core/java/android/hardware/camera2/extension/ExtensionConfiguration.java
+++ b/core/java/android/hardware/camera2/extension/ExtensionConfiguration.java
@@ -20,7 +20,9 @@ import android.annotation.FlaggedApi;
 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.annotation.SystemApi;
+import android.hardware.camera2.CameraDevice;
 import android.hardware.camera2.CaptureRequest;
+import android.os.IBinder;
 
 import com.android.internal.camera.flags.Flags;
 
@@ -28,6 +30,15 @@ import java.util.ArrayList;
 import java.util.List;
 
 /**
+ * Helper class used to guide the camera framework when
+ * initializing the internal camera capture session.
+ * It contains all required internal outputs, parameters,
+ * modes and settings.
+ *
+ * <p>Extension must decide the final set of output surfaces
+ * and pass an instance of ExtensionConfiguration as part
+ * of the result during calls to {@link SessionProcessor#initSession}.</p>
+ *
  * @hide
  */
 @SystemApi
@@ -38,9 +49,25 @@ public class ExtensionConfiguration {
     private final List<ExtensionOutputConfiguration> mOutputs;
     private final CaptureRequest mSessionParameters;
 
+    /**
+     * Initialize an extension configuration instance
+     *
+     * @param sessionType       The type of camera capture session
+     *                          operating mode to be used
+     * @param sessionTemplateId The request template id to be used
+     *                          for generating the session parameter
+     *                          capture request
+     * @param outputs           List of {@link ExtensionOutputConfiguration}
+     *                          camera outputs to be configured
+     *                          as part of the capture session
+     * @param sessionParams     An optional set of camera capture
+     *                          session parameter values
+     */
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
-    public ExtensionConfiguration(int sessionType, int sessionTemplateId, @NonNull
-            List<ExtensionOutputConfiguration> outputs, @Nullable CaptureRequest sessionParams) {
+    public ExtensionConfiguration(@CameraDevice.SessionOperatingMode int sessionType,
+            @CameraDevice.RequestTemplate int sessionTemplateId,
+            @NonNull List<ExtensionOutputConfiguration> outputs,
+            @Nullable CaptureRequest sessionParams) {
         mSessionType = sessionType;
         mSessionTemplateId = sessionTemplateId;
         mOutputs = outputs;
diff --git a/core/java/android/hardware/camera2/extension/ExtensionOutputConfiguration.java b/core/java/android/hardware/camera2/extension/ExtensionOutputConfiguration.java
index 85d180d379df..9dc6d7bf94b3 100644
--- a/core/java/android/hardware/camera2/extension/ExtensionOutputConfiguration.java
+++ b/core/java/android/hardware/camera2/extension/ExtensionOutputConfiguration.java
@@ -27,6 +27,10 @@ import java.util.ArrayList;
 import java.util.List;
 
 /**
+ * Helper class used to describe a single camera
+ * output configuration that is intended to be configured
+ * internally by the extension implementation.
+ *
  * @hide
  */
 @SystemApi
@@ -37,6 +41,21 @@ public class ExtensionOutputConfiguration {
     private final int mOutputConfigId;
     private final int mSurfaceGroupId;
 
+    /**
+     * Initialize an extension output configuration instance
+     *
+     * @param outputs           List of camera {@link CameraOutputSurface outputs}.
+     *                          The list may include more than one entry
+     *                          only in case of shared camera outputs.
+     *                          In all other cases the list will only include
+     *                          a single entry.
+     * @param outputConfigId    Unique output configuration id used to identify
+     *                          this particular configuration.
+     * @param physicalCameraId  In case of physical camera capture, this field
+     *                          must contain a valid physical camera id.
+     * @param surfaceGroupId    In case of surface group, this field must
+     *                          contain the surface group id
+     */
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
     public ExtensionOutputConfiguration(@NonNull List<CameraOutputSurface> outputs,
             int outputConfigId, @Nullable String physicalCameraId, int surfaceGroupId) {
diff --git a/core/java/android/hardware/camera2/extension/RequestProcessor.java b/core/java/android/hardware/camera2/extension/RequestProcessor.java
index bf5ea12df358..0ad27c212d67 100644
--- a/core/java/android/hardware/camera2/extension/RequestProcessor.java
+++ b/core/java/android/hardware/camera2/extension/RequestProcessor.java
@@ -20,7 +20,9 @@ import android.annotation.FlaggedApi;
 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.annotation.SystemApi;
+import android.hardware.camera2.CameraAccessException;
 import android.hardware.camera2.CameraCharacteristics;
+import android.hardware.camera2.CameraDevice;
 import android.hardware.camera2.CaptureFailure;
 import android.hardware.camera2.CaptureRequest;
 import android.hardware.camera2.CaptureResult;
@@ -69,6 +71,8 @@ public final class RequestProcessor {
          *                  regular request, or the timestamp at the input
          *                  image's start of capture for a
          *                  reprocess request, in nanoseconds.
+         *                  The timestamp matches with and uses the same
+         *                  time base as {@link CaptureResult#SENSOR_TIMESTAMP}.
          * @param frameNumber the frame number for this capture
          *
          */
@@ -225,11 +229,12 @@ public final class RequestProcessor {
     public final static class Request {
         private final List<Integer> mOutputIds;
         private final List<Pair<CaptureRequest.Key, Object>> mParameters;
-        private final int mTemplateId;
+        private final @CameraDevice.RequestTemplate int mTemplateId;
 
         @FlaggedApi(Flags.FLAG_CONCERT_MODE)
         public Request(@NonNull List<Integer> outputConfigIds,
-                @NonNull List<Pair<CaptureRequest.Key, Object>> parameters, int templateId) {
+                @NonNull List<Pair<CaptureRequest.Key, Object>> parameters,
+                @CameraDevice.RequestTemplate int templateId) {
             mOutputIds = outputConfigIds;
             mParameters = parameters;
             mTemplateId = templateId;
@@ -255,7 +260,10 @@ public final class RequestProcessor {
         }
 
         /**
-         * Gets the template id.
+         * Gets the request {@link android.hardware.camera2.CameraDevice.RequestTemplate template}
+         * id.
+         *
+         * @see CameraDevice.RequestTemplate
          */
         @FlaggedApi(Flags.FLAG_CONCERT_MODE)
         Integer getTemplateId() {
@@ -310,26 +318,32 @@ public final class RequestProcessor {
      * Submit a capture request.
      * @param request  Capture request to queued in the Camera2 session
      * @param executor the executor which will be used for
-     *                 invoking the callbacks or null to use the
-     *                 current thread's looper
+     *                 invoking the callbacks
      * @param callback Request callback implementation
-     * @return the id of the capture sequence or -1 in case the processor
-     *         encounters a fatal error or receives an invalid argument.
+     * @return the id of the capture sequence
      */
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
-    public int submit(@NonNull Request request, @Nullable Executor executor,
-            @NonNull RequestCallback callback) {
+    public int submit(@NonNull Request request, @NonNull Executor executor,
+            @NonNull RequestCallback callback) throws CameraAccessException {
         ArrayList<Request> requests = new ArrayList<>(1);
         requests.add(0, request);
         List<android.hardware.camera2.extension.Request> parcelableRequests =
                 Request.initializeParcelable(mVendorId, requests);
 
+        int ret = -1;
         try {
-            return mRequestProcessor.submit(parcelableRequests.get(0),
+            ret = mRequestProcessor.submit(parcelableRequests.get(0),
                     new RequestCallbackImpl(requests, callback, executor));
         } catch (RemoteException e) {
             throw new RuntimeException(e);
         }
+
+        if (ret == -1) {
+            throw new CameraAccessException(CameraAccessException.CAMERA_ERROR,
+                    "Failed to submit capture request");
+        }
+
+        return ret;
     }
 
     /**
@@ -337,24 +351,30 @@ public final class RequestProcessor {
      * @param requests List of capture requests to be queued in the
      *                 Camera2 session
      * @param executor the executor which will be used for
-     *                 invoking the callbacks or null to use the
-     *                 current thread's looper
+     *                 invoking the callbacks
      * @param callback Request callback implementation
-     * @return the id of the capture sequence or -1 in case the processor
-     *         encounters a fatal error or receives an invalid argument.
+     * @return the id of the capture sequence
      */
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
-    public int submitBurst(@NonNull List<Request> requests, @Nullable Executor executor,
-            @NonNull RequestCallback callback) {
+    public int submitBurst(@NonNull List<Request> requests, @NonNull Executor executor,
+            @NonNull RequestCallback callback) throws CameraAccessException {
         List<android.hardware.camera2.extension.Request> parcelableRequests =
                 Request.initializeParcelable(mVendorId, requests);
 
+        int ret = -1;
         try {
-            return mRequestProcessor.submitBurst(parcelableRequests,
+            ret = mRequestProcessor.submitBurst(parcelableRequests,
                     new RequestCallbackImpl(requests, callback, executor));
         } catch (RemoteException e) {
             throw new RuntimeException(e);
         }
+
+        if (ret == -1) {
+            throw new CameraAccessException(CameraAccessException.CAMERA_ERROR,
+                    "Failed to submit burst request");
+        }
+
+        return ret;
     }
 
     /**
@@ -362,26 +382,32 @@ public final class RequestProcessor {
      * @param request  Repeating capture request to be se in the
      *                 Camera2 session
      * @param executor the executor which will be used for
-     *                 invoking the callbacks or null to use the
-     *                 current thread's looper
+     *                 invoking the callbacks
      * @param callback Request callback implementation
-     * @return the id of the capture sequence or -1 in case the processor
-     *         encounters a fatal error or receives an invalid argument.
+     * @return the id of the capture sequence
      */
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
-    public int setRepeating(@NonNull Request request, @Nullable Executor executor,
-            @NonNull RequestCallback callback) {
+    public int setRepeating(@NonNull Request request, @NonNull Executor executor,
+            @NonNull RequestCallback callback) throws CameraAccessException {
         ArrayList<Request> requests = new ArrayList<>(1);
         requests.add(0, request);
         List<android.hardware.camera2.extension.Request> parcelableRequests =
                 Request.initializeParcelable(mVendorId, requests);
 
+        int ret = -1;
         try {
-            return mRequestProcessor.setRepeating(parcelableRequests.get(0),
+            ret = mRequestProcessor.setRepeating(parcelableRequests.get(0),
                     new RequestCallbackImpl(requests, callback, executor));
         } catch (RemoteException e) {
             throw new RuntimeException(e);
         }
+        if (ret == -1) {
+            throw new CameraAccessException(CameraAccessException.CAMERA_ERROR,
+                    "Failed to set the repeating request");
+
+        }
+
+        return ret;
     }
 
     /**
@@ -414,7 +440,7 @@ public final class RequestProcessor {
         private final Executor mExecutor;
 
         public RequestCallbackImpl(@NonNull List<Request> requests,
-                @NonNull RequestCallback callback, @Nullable Executor executor) {
+                @NonNull RequestCallback callback, @NonNull Executor executor) {
             mCallback = callback;
             mRequests = requests;
             mExecutor = executor;
@@ -425,13 +451,8 @@ public final class RequestProcessor {
             if (mRequests.get(requestId) != null) {
                 final long ident = Binder.clearCallingIdentity();
                 try {
-                    if (mExecutor != null) {
-                        mExecutor.execute(() -> mCallback.onCaptureStarted(
-                                mRequests.get(requestId), frameNumber, timestamp));
-                    } else {
-                        mCallback.onCaptureStarted(mRequests.get(requestId), frameNumber,
-                                timestamp);
-                    }
+                    mExecutor.execute(() -> mCallback.onCaptureStarted(
+                            mRequests.get(requestId), frameNumber, timestamp));
                 } finally {
                     Binder.restoreCallingIdentity(ident);
                 }
@@ -448,14 +469,9 @@ public final class RequestProcessor {
                         partialResult.frameNumber);
                 final long ident = Binder.clearCallingIdentity();
                 try {
-                    if (mExecutor != null) {
-                        mExecutor.execute(
-                                () -> mCallback.onCaptureProgressed(mRequests.get(requestId),
-                                        result));
-                    } else {
-                        mCallback.onCaptureProgressed(mRequests.get(requestId), result);
-                    }
-
+                    mExecutor.execute(
+                            () -> mCallback.onCaptureProgressed(mRequests.get(requestId),
+                                    result));
                 } finally {
                     Binder.restoreCallingIdentity(ident);
                 }
@@ -489,13 +505,9 @@ public final class RequestProcessor {
                         physicalResults);
                 final long ident = Binder.clearCallingIdentity();
                 try {
-                    if (mExecutor != null) {
-                        mExecutor.execute(
-                                () -> mCallback.onCaptureCompleted(mRequests.get(requestId),
-                                        result));
-                    } else {
-                        mCallback.onCaptureCompleted(mRequests.get(requestId), result);
-                    }
+                    mExecutor.execute(
+                            () -> mCallback.onCaptureCompleted(mRequests.get(requestId),
+                                    result));
                 } finally {
                     Binder.restoreCallingIdentity(ident);
                 }
@@ -515,12 +527,8 @@ public final class RequestProcessor {
                                 captureFailure.errorPhysicalCameraId);
                 final long ident = Binder.clearCallingIdentity();
                 try {
-                    if (mExecutor != null) {
-                        mExecutor.execute(() -> mCallback.onCaptureFailed(mRequests.get(requestId),
-                                failure));
-                    } else {
-                        mCallback.onCaptureFailed(mRequests.get(requestId), failure);
-                    }
+                    mExecutor.execute(() -> mCallback.onCaptureFailed(mRequests.get(requestId),
+                            failure));
                 } finally {
                     Binder.restoreCallingIdentity(ident);
                 }
@@ -534,14 +542,9 @@ public final class RequestProcessor {
             if (mRequests.get(requestId) != null) {
                 final long ident = Binder.clearCallingIdentity();
                 try {
-                    if (mExecutor != null) {
-                        mExecutor.execute(
-                                () -> mCallback.onCaptureBufferLost(mRequests.get(requestId),
-                                        frameNumber, outputStreamId));
-                    } else {
-                        mCallback.onCaptureBufferLost(mRequests.get(requestId), frameNumber,
-                                outputStreamId);
-                    }
+                    mExecutor.execute(
+                            () -> mCallback.onCaptureBufferLost(mRequests.get(requestId),
+                                    frameNumber, outputStreamId));
                 } finally {
                     Binder.restoreCallingIdentity(ident);
                 }
@@ -554,12 +557,8 @@ public final class RequestProcessor {
         public void onCaptureSequenceCompleted(int sequenceId, long frameNumber) {
             final long ident = Binder.clearCallingIdentity();
             try {
-                if (mExecutor != null) {
-                    mExecutor.execute(() -> mCallback.onCaptureSequenceCompleted(sequenceId,
-                            frameNumber));
-                } else {
-                    mCallback.onCaptureSequenceCompleted(sequenceId, frameNumber);
-                }
+                mExecutor.execute(() -> mCallback.onCaptureSequenceCompleted(sequenceId,
+                        frameNumber));
             } finally {
                 Binder.restoreCallingIdentity(ident);
             }
@@ -569,11 +568,7 @@ public final class RequestProcessor {
         public void onCaptureSequenceAborted(int sequenceId) {
             final long ident = Binder.clearCallingIdentity();
             try {
-                if (mExecutor != null) {
-                    mExecutor.execute(() -> mCallback.onCaptureSequenceAborted(sequenceId));
-                } else {
-                    mCallback.onCaptureSequenceAborted(sequenceId);
-                }
+                mExecutor.execute(() -> mCallback.onCaptureSequenceAborted(sequenceId));
             } finally {
                 Binder.restoreCallingIdentity(ident);
             }
diff --git a/core/java/android/hardware/camera2/extension/SessionProcessor.java b/core/java/android/hardware/camera2/extension/SessionProcessor.java
index 9c5136bcf903..e7cc5303fc18 100644
--- a/core/java/android/hardware/camera2/extension/SessionProcessor.java
+++ b/core/java/android/hardware/camera2/extension/SessionProcessor.java
@@ -18,13 +18,15 @@ package android.hardware.camera2.extension;
 
 import android.annotation.FlaggedApi;
 import android.annotation.NonNull;
-import android.annotation.Nullable;
 import android.annotation.SystemApi;
 import android.hardware.camera2.CameraCharacteristics;
 import android.hardware.camera2.CaptureRequest;
 import android.hardware.camera2.CaptureResult;
+import android.hardware.camera2.impl.CameraExtensionUtils.HandlerExecutor;
 import android.hardware.camera2.impl.CameraMetadataNative;
+import android.os.Handler;
 import android.os.IBinder;
+import android.os.Looper;
 import android.os.RemoteException;
 import android.util.Log;
 
@@ -60,7 +62,7 @@ import java.util.concurrent.Executor;
  * to the repeating request and single requests but the implementation can
  * choose to apply some of them only.
  *
- * (5) {@link #startCapture}: It is called when apps want
+ * (5) {@link #startMultiFrameCapture}: It is called when apps want
  * to start a multi-frame image capture.  {@link CaptureCallback} will be
  * called to report the status and the output image will be written to the
  * capture output surface specified in {@link #initSession}.
@@ -78,8 +80,11 @@ public abstract class SessionProcessor {
     private static final String TAG = "SessionProcessor";
     private CameraUsageTracker mCameraUsageTracker;
 
+    /**
+     * Initialize a session process instance
+     */
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
-    protected SessionProcessor() {}
+    public SessionProcessor() {}
 
     void setCameraUsageTracker(CameraUsageTracker tracker) {
         mCameraUsageTracker = tracker;
@@ -87,7 +92,7 @@ public abstract class SessionProcessor {
 
     /**
      * Callback for notifying the status of {@link
-     * #startCapture} and {@link #startRepeating}.
+     * #startMultiFrameCapture} and {@link #startRepeating}.
      * @hide
      */
     @SystemApi
@@ -175,7 +180,7 @@ public abstract class SessionProcessor {
          * @param requestId  the capture request id that generated the
          *                   capture results. This is the return value of
          *                   either {@link #startRepeating} or {@link
-         *                   #startCapture}.
+         *                   #startMultiFrameCapture}.
          * @param results  The supported capture results. Do note
          *                  that if results 'android.jpeg.quality' and
          *                  android.jpeg.orientation' are present in the
@@ -252,7 +257,14 @@ public abstract class SessionProcessor {
      * until onCaptureSessionEnd is called.
      * @param requestProcessor The request processor to be used for
      *                         managing capture requests
-     * @param statsKey         Unique key for telemetry
+     * @param statsKey         Unique key that is associated with the
+     *                         current Camera2 session and used by the
+     *                         framework telemetry. The id can be referenced
+     *                         by the extension, in case there is additional
+     *                         extension specific telemetry that needs
+     *                         to be linked to the regular capture session.
+     *
+     *
      */
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
     public abstract void onCaptureSessionStart(@NonNull RequestProcessor requestProcessor,
@@ -275,13 +287,12 @@ public abstract class SessionProcessor {
      * repeating request when needed later.
      *
      * @param executor the executor which will be used for
-     *                 invoking the callbacks or null to use the
-     *                 current thread's looper
+     *                 invoking the callbacks
      * @param callback a callback to report the status.
      * @return the id of the capture sequence.
      */
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
-    public abstract int startRepeating(@Nullable Executor executor,
+    public abstract int startRepeating(@NonNull Executor executor,
             @NonNull CaptureCallback callback);
 
     /**
@@ -309,13 +320,12 @@ public abstract class SessionProcessor {
      * immediately.
      *
      * @param executor the executor which will be used for
-     *                 invoking the callbacks or null to use the
-     *                 current thread's looper
+     *                 invoking the callbacks
      * @param callback a callback to report the status.
      * @return the id of the capture sequence.
      */
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
-    public abstract int startCapture(@Nullable Executor executor,
+    public abstract int startMultiFrameCapture(@NonNull Executor executor,
             @NonNull CaptureCallback callback);
 
     /**
@@ -340,15 +350,14 @@ public abstract class SessionProcessor {
      * @param captureRequest Capture request that includes the respective
      *                       triggers.
      * @param executor the executor which will be used for
-     *                 invoking the callbacks or null to use the
-     *                 current thread's looper
+     *                 invoking the callbacks
      * @param callback a callback to report the status.
      * @return the id of the capture sequence.
      *
      */
     @FlaggedApi(Flags.FLAG_CONCERT_MODE)
     public abstract int startTrigger(@NonNull CaptureRequest captureRequest,
-            @Nullable Executor executor, @NonNull CaptureCallback callback);
+            @NonNull Executor executor, @NonNull CaptureCallback callback);
 
     private final class SessionProcessorImpl extends ISessionProcessorImpl.Stub {
         private long mVendorId = -1;
@@ -401,7 +410,8 @@ public abstract class SessionProcessor {
 
         @Override
         public int startRepeating(ICaptureCallback callback) throws RemoteException {
-            return SessionProcessor.this.startRepeating(/*executor*/ null,
+            return SessionProcessor.this.startRepeating(
+                    new HandlerExecutor(new Handler(Looper.getMainLooper())),
                     new CaptureCallbackImpl(callback));
         }
 
@@ -413,7 +423,8 @@ public abstract class SessionProcessor {
         @Override
         public int startCapture(ICaptureCallback callback, boolean isPostviewRequested)
                 throws RemoteException {
-            return SessionProcessor.this.startCapture(/*executor*/ null,
+            return SessionProcessor.this.startMultiFrameCapture(
+                    new HandlerExecutor(new Handler(Looper.getMainLooper())),
                     new CaptureCallbackImpl(callback));
         }
 
@@ -425,7 +436,8 @@ public abstract class SessionProcessor {
         @Override
         public int startTrigger(CaptureRequest captureRequest, ICaptureCallback callback)
                 throws RemoteException {
-            return SessionProcessor.this.startTrigger(captureRequest, /*executor*/ null,
+            return SessionProcessor.this.startTrigger(captureRequest,
+                    new HandlerExecutor(new Handler(Looper.getMainLooper())),
                     new CaptureCallbackImpl(callback));
         }