Remove TFLite Java runtime dependency in the metadata java lib

PiperOrigin-RevId: 312601579
Change-Id: I57d7bfe06d36e62a6fa203c39225687861fa4580

tensorflow/lite/experimental/support/java/src/java/org/tensorflow/lite/support/model/Model.java

@@ -22,6 +22,7 @@ import java.util.Map;
 import org.checkerframework.checker.nullness.qual.NonNull;
 import org.checkerframework.checker.nullness.qual.Nullable;
 import org.tensorflow.lite.Interpreter;
+import org.tensorflow.lite.Tensor;
 import org.tensorflow.lite.support.common.FileUtil;
 import org.tensorflow.lite.support.common.SupportPreconditions;
 
@@ -218,6 +219,24 @@ public class Model {
     return modelPath;
   }
 
+  /**
+   * Gets the Tensor associated with the provdied input index.
+   *
+   * @throws IllegalStateException if the interpreter is closed.
+   */
+  public Tensor getInputTensor(int inputIndex) {
+    return interpreter.getInputTensor(inputIndex);
+  }
+
+  /**
+   * Gets the Tensor associated with the provdied output index.
+   *
+   * @throws IllegalStateException if the interpreter is closed.
+   */
+  public Tensor getOutputTensor(int outputIndex) {
+    return interpreter.getOutputTensor(outputIndex);
+  }
+
   /**
    * Returns the output shape. Useful if output shape is only determined when graph is created.
    *

tensorflow/lite/experimental/support/metadata/java/BUILD

@@ -16,7 +16,6 @@ android_library(
     deps = [
         "//tensorflow/lite/experimental/support/metadata:metadata_schema_fbs_android",
         "//tensorflow/lite/experimental/support/metadata:schema_fbs_android",
-        "//tensorflow/lite/java:tensorflowlite_java",
         "@org_checkerframework_qual",
     ],
 )
@@ -32,7 +31,6 @@ java_library(
     deps = [
         "//tensorflow/lite/experimental/support/metadata:metadata_schema_java",
         "//tensorflow/lite/experimental/support/metadata:schema_fbs_java",
-        "//tensorflow/lite/java:tensorflowlite_javalib",
         "@org_checkerframework_qual",
     ],
 )

tensorflow/lite/experimental/support/metadata/java/src/java/org/tensorflow/lite/support/metadata/MetadataExtractor.java

@@ -22,8 +22,6 @@ import java.io.InputStream;
 import java.nio.ByteBuffer;
 import java.util.zip.ZipException;
 import org.checkerframework.checker.nullness.qual.Nullable;
-import org.tensorflow.lite.DataType;
-import org.tensorflow.lite.Tensor.QuantizationParams;
 import org.tensorflow.lite.schema.Tensor;
 import org.tensorflow.lite.support.metadata.schema.ModelMetadata;
 import org.tensorflow.lite.support.metadata.schema.TensorMetadata;
@@ -111,6 +109,48 @@ public class MetadataExtractor {
     zipFile = createZipFile(buffer);
   }
 
+  /**
+   * Quantization parameters that corresponds to the table, {@code QuantizationParameters}, in the
+   * <a
+   * href="https://github.com/tensorflow/tensorflow/blob/master/tensorflow/lite/schema/schema.fbs">TFLite
+   * Model schema file.</a>
+   *
+   * <p>Since per-channel quantization does not apply to input and output tensors, {@code scale} and
+   * {@code zero_point} are both single values instead of arrays.
+   *
+   * <p>For tensor that are not quantized, the values of scale and zero_point are both 0.
+   *
+   * <p>Given a quantized value q, the corresponding float value f should be: <br>
+   * f = scale * (q - zero_point) <br>
+   */
+  public static class QuantizationParams {
+    /** The scale value used in quantization. */
+    private final float scale;
+    /** The zero point value used in quantization. */
+    private final int zeroPoint;
+
+    /**
+     * Creates a {@link QuantizationParams} with {@code scale} and {@code zero_point}.
+     *
+     * @param scale The scale value used in quantization.
+     * @param zeroPoint The zero point value used in quantization.
+     */
+    public QuantizationParams(final float scale, final int zeroPoint) {
+      this.scale = scale;
+      this.zeroPoint = zeroPoint;
+    }
+
+    /** Returns the scale value. */
+    public float getScale() {
+      return scale;
+    }
+
+    /** Returns the zero point value. */
+    public int getZeroPoint() {
+      return zeroPoint;
+    }
+  }
+
   /** Returns {@code true} if the model has metadata. Otherwise, returns {@code false}. */
   public boolean hasMetadata() {
     return metadataInfo != null;
@@ -166,11 +206,11 @@ public class MetadataExtractor {
   }
 
   /**
-   * Gets the {@link DataType} of the input tensor with {@code inputIndex}.
+   * Gets the {@link TensorType} of the input tensor with {@code inputIndex}.
    *
    * @param inputIndex the index of the desired input tensor
    */
-  public DataType getInputTensorType(int inputIndex) {
+  public byte getInputTensorType(int inputIndex) {
     return modelInfo.getInputTensorType(inputIndex);
   }
 
@@ -221,11 +261,11 @@ public class MetadataExtractor {
   }
 
   /**
-   * Gets the {@link DataType} of the output tensor with {@code outputIndex}.
+   * Gets the {@link TensorType} of the output tensor with {@code outputIndex}.
    *
    * @param outputIndex the index of the desired output tensor
    */
-  public DataType getOutputTensorType(int outputIndex) {
+  public byte getOutputTensorType(int outputIndex) {
     return modelInfo.getOutputTensorType(outputIndex);
   }
 

tensorflow/lite/experimental/support/metadata/java/src/java/org/tensorflow/lite/support/metadata/ModelInfo.java

@@ -21,12 +21,8 @@ import static org.tensorflow.lite.support.metadata.Preconditions.checkNotNull;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.List;
-import java.util.Map;
 import org.checkerframework.checker.nullness.qual.Nullable;
-import org.tensorflow.lite.DataType;
-import org.tensorflow.lite.Tensor.QuantizationParams;
 import org.tensorflow.lite.schema.Buffer;
 import org.tensorflow.lite.schema.Metadata;
 import org.tensorflow.lite.schema.Model;
@@ -34,6 +30,7 @@ import org.tensorflow.lite.schema.QuantizationParameters;
 import org.tensorflow.lite.schema.SubGraph;
 import org.tensorflow.lite.schema.Tensor;
 import org.tensorflow.lite.schema.TensorType;
+import org.tensorflow.lite.support.metadata.MetadataExtractor.QuantizationParams;
 
 /** Extracts model information out of TFLite model FLatBuffer. */
 final class ModelInfo {
@@ -49,9 +46,6 @@ final class ModelInfo {
   /** Identifier of the TFLite model metadata in the Metadata array. */
   static final String METADATA_FIELD_NAME = "TFLITE_METADATA";
 
-  /** Maps from TensorType in TFlite FlatBuffer to {@link DataType} in Java. */
-  private final Map<Byte, DataType> tensorTypeToDataTypeMap;
-
   /**
    * Creates a {@link ModelInfo} with the model FlatBuffer, {@code buffer}.
    *
@@ -74,7 +68,6 @@ final class ModelInfo {
 
     inputTensors = getInputTensors(model);
     outputTensors = getOutputTensors(model);
-    tensorTypeToDataTypeMap = createTensorTypeToDataTypeMap();
   }
 
   /**
@@ -106,13 +99,12 @@ final class ModelInfo {
   }
 
   /**
-   * Gets {@link DataType} of the input tensor with {@code inputIndex}.
+   * Gets the {@link TensorType} in byte of the input tensor with {@code inputIndex}.
    *
    * @param inputIndex The index of the desired intput tensor.
    */
-  DataType getInputTensorType(int inputIndex) {
-    Tensor tensor = getInputTensor(inputIndex);
-    return getDataType(tensor.type());
+  byte getInputTensorType(int inputIndex) {
+    return getInputTensor(inputIndex).type();
   }
 
   /** Gets the metadata FlatBuffer from the model FlatBuffer. */
@@ -163,13 +155,12 @@ final class ModelInfo {
   }
 
   /**
-   * Gets {@link DataType} of the output tensor {@code outputIndex}.
+   * Gets the {@link TensorType} in byte of the output tensor {@code outputIndex}.
    *
    * @param outputIndex The index of the desired outtput tensor.
    */
-  DataType getOutputTensorType(int outputIndex) {
-    Tensor tensor = getOutputTensor(outputIndex);
-    return getDataType(tensor.type());
+  byte getOutputTensorType(int outputIndex) {
+    return getOutputTensor(outputIndex).type();
   }
 
   /**
@@ -233,29 +224,6 @@ final class ModelInfo {
             + " flatbuffer.");
   }
 
-  private static Map<Byte, DataType> createTensorTypeToDataTypeMap() {
-    Map<Byte, DataType> map = new HashMap<>();
-    map.put(TensorType.FLOAT32, DataType.FLOAT32);
-    map.put(TensorType.INT32, DataType.INT32);
-    map.put(TensorType.UINT8, DataType.UINT8);
-    map.put(TensorType.INT64, DataType.INT64);
-    map.put(TensorType.STRING, DataType.STRING);
-    return Collections.unmodifiableMap(map);
-  }
-
-  /**
-   * Transforms from TensorType in TFlite FlatBuffer to {@link DataType} in Java.
-   *
-   * @param tensorType The tensor type to be converted.
-   * @throws IllegalArgumentException if the tensor type is not supported.
-   */
-  private DataType getDataType(byte tensorType) {
-    checkArgument(
-        tensorTypeToDataTypeMap.containsKey(tensorType),
-        String.format("Tensor type %d is not supported.", tensorType));
-    return tensorTypeToDataTypeMap.get(tensorType);
-  }
-
   /**
    * Gets the shape of a tensor.
    *