[WIP] tf.Variable like API for variables

tensorflow-core/tensorflow-core-api/src/gen/annotations/org/tensorflow/op/Ops.java

@@ -278,7 +278,6 @@
 import org.tensorflow.op.core.Unstage;
 import org.tensorflow.op.core.VarHandleOp;
 import org.tensorflow.op.core.VarIsInitializedOp;
-import org.tensorflow.op.core.Variable;
 import org.tensorflow.op.core.VariableShape;
 import org.tensorflow.op.core.Where;
 import org.tensorflow.op.core.XlaSpmdFullToShardShape;
@@ -294,6 +293,7 @@
 import org.tensorflow.types.TUint8;
 import org.tensorflow.types.family.TNumber;
 import org.tensorflow.types.family.TType;
+import org.tensorflow.variable.Variable;
 
 /**
  * An API for building operations as {@link Op Op}s
@@ -394,6 +394,43 @@ private Ops(Scope scope) {
     quantization = new QuantizationOps(this);
   }
 
+  /**
+   * Create a new {@link Variable} object, representing a mutable tensor value with constant shape and data type, with
+   *  support for assignment and initialization that works in both eager and graph modes.
+   *  <p>
+   *  Initializes the variable with the provided value, and uses it to determin the variables shape and data type.
+   *  <p>
+   *  The name can be set using {@link org.tensorflow.op.Ops#withName(String)} just like any other op.
+   *
+   * @param scope
+   * @param initialValue the initial value of the variable.
+   * @param options carries optional attributes values
+   * @return a new {@link Variable} instance.
+   * @see Variable
+   */
+  public <T extends TType> Variable<T> Variable(Operand<T> initialValue,
+      Variable.Options... options) {
+    return Variable.create(scope, initialValue, options);
+  }
+
+  /**
+   * Create a new {@link Variable} object, representing a mutable tensor value with constant shape and data type, with
+   *  support for assignment and initialization that works in both eager and graph modes.
+   *  <p>
+   *  The name can be set using {@link org.tensorflow.op.Ops#withName(String)} just like any other op.
+   *
+   * @param scope
+   * @param shape the static shape of the variable.
+   * @param dataType the data type of the variable.
+   * @param options carries optional attributes values
+   * @return a new {@link Variable} instance.
+   * @see Variable
+   */
+  public <T extends TType> Variable<T> Variable(Shape shape, Class<T> dataType,
+      Variable.Options... options) {
+    return Variable.create(scope, shape, dataType, options);
+  }
+
   /**
    * Raise a exception to abort the process when called.
    *  <p>
@@ -7947,8 +7984,11 @@ public VarIsInitializedOp varIsInitializedOp(Operand<?> resource) {
    * @param init The op to use to initialise this variable.
    * @param options carries optional attributes values
    * @return a new instance of Variable
+   * @deprecated Use {@link org.tensorflow.op.Ops#Variable(Operand)} instead for a tf.Variable like API.
    */
-  public <T extends TType> Variable<T> variable(Operand<T> init, Variable.Options... options) {
+  @Deprecated
+  public <T extends TType> org.tensorflow.op.core.Variable<T> variable(Operand<T> init,
+      org.tensorflow.op.core.Variable.Options... options) {
     return Helpers.createVariableWithInit(scope, init, options);
   }
 
@@ -7964,10 +8004,12 @@ public <T extends TType> Variable<T> variable(Operand<T> init, Variable.Options.
    * @param dtype The type of elements in the variable tensor.
    * @param options carries optional attributes values
    * @return a new instance of Variable
+   * @deprecated Use {@link org.tensorflow.op.Ops#Variable(Shape, DataType)} instead for a tf.Variable like API.
    */
-  public <T extends TType> Variable<T> variable(Shape shape, Class<T> dtype,
-      Variable.Options... options) {
-    return Variable.create(scope, shape, dtype, options);
+  @Deprecated
+  public <T extends TType> org.tensorflow.op.core.Variable<T> variable(Shape shape, Class<T> dtype,
+      org.tensorflow.op.core.Variable.Options... options) {
+    return org.tensorflow.op.core.Variable.create(scope, shape, dtype, options);
   }
 
   /**

tensorflow-core/tensorflow-core-api/src/gen/java/org/tensorflow/op/core/Variable.java

@@ -79,8 +79,10 @@ private Options() {
    * @param dtype The type of elements in the variable tensor.
    * @param options carries optional attributes values
    * @return a new instance of Variable
+   * @deprecated Use {@link org.tensorflow.op.Ops#Variable(Shape, DataType)} instead for a tf.Variable like API.
    */
   @Endpoint(describeByClass = true)
+  @Deprecated
   public static <T extends TType> Variable<T> create(Scope scope, Shape shape, Class<T> dtype, Options... options) {
     OperationBuilder opBuilder = scope.env().opBuilder("VariableV2", scope.makeOpName("Variable"));
     opBuilder = scope.apply(opBuilder);

tensorflow-core/tensorflow-core-api/src/main/java/org/tensorflow/EagerSession.java

@@ -21,6 +21,9 @@
 import static org.tensorflow.internal.c_api.global.tensorflow.TFE_DeleteContext;
 import static org.tensorflow.internal.c_api.global.tensorflow.TFE_NewContext;
 
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.Map;
 import org.bytedeco.javacpp.BytePointer;
 import org.bytedeco.javacpp.Pointer;
 import org.bytedeco.javacpp.PointerScope;
@@ -31,8 +34,8 @@
 import org.tensorflow.op.Op;
 import org.tensorflow.op.core.Assign;
 import org.tensorflow.op.core.Placeholder;
-import org.tensorflow.op.core.Variable;
 import org.tensorflow.proto.framework.ConfigProto;
+import org.tensorflow.variable.Variable;
 
 /**
  * An environment for executing TensorFlow operations eagerly.
@@ -290,7 +293,7 @@ public Types environmentType() {
   @Override
   public boolean isOpEnabled(String opType) {
     switch (opType) {
-      case Variable.OP_NAME:
+      case org.tensorflow.op.core.Variable.OP_NAME:
       case Placeholder.OP_NAME:
       case Assign.OP_NAME:
         return false;
@@ -357,6 +360,18 @@ void detach(Pointer... resources) {
     }
   }
 
+  private final Map<String, Variable<?>> variables = new LinkedHashMap<>();
+
+  @Override
+  public void registerVariable(Variable<?> variable) {
+    variables.put(variable.getName(), variable);
+  }
+
+  @Override
+  public Map<String, Variable<?>> variables() {
+    return Collections.unmodifiableMap(variables);
+  }
+
   private static volatile EagerSession defaultSession = null;
 
   private final WeakPointerScope nativeResources;

tensorflow-core/tensorflow-core-api/src/main/java/org/tensorflow/ExecutionEnvironment.java

@@ -16,10 +16,9 @@
 package org.tensorflow;
 
 import org.tensorflow.op.Op;
-
-/**
- * Defines an environment for creating and executing TensorFlow {@link Operation}s.
- */
+import java.util.Map;
+import org.tensorflow.variable.Variable;
+/** Defines an environment for creating and executing TensorFlow {@link Operation}s. */
 public interface ExecutionEnvironment {
 
   enum Types {
@@ -64,6 +63,13 @@ default boolean isOpEnabled(String opType) {
    */
   Types environmentType();
 
+  Map<String, Variable<?>> variables();
+
+  /**
+   * Registers a variable with this execution environment.  For internal use only.
+   */
+  void registerVariable(Variable<?> variable);
+
   default boolean isEager() {
     return environmentType() == Types.EAGER;
   }

tensorflow-core/tensorflow-core-api/src/main/java/org/tensorflow/Graph.java

@@ -31,7 +31,9 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.Iterator;
+import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Map;
 import org.bytedeco.javacpp.BytePointer;
 import org.bytedeco.javacpp.Pointer;
 import org.bytedeco.javacpp.PointerScope;
@@ -57,6 +59,7 @@
 import org.tensorflow.proto.util.SaverDef;
 import org.tensorflow.types.TString;
 import org.tensorflow.types.family.TType;
+import org.tensorflow.variable.Variable;
 
 
 /**
@@ -478,6 +481,18 @@ synchronized SaverDef saverDef() {
 
   private final List<Op> initializers = new ArrayList<>();
 
+  private final Map<String, Variable<?>> variables = new LinkedHashMap<>();
+
+  @Override
+  public void registerVariable(Variable<?> variable) {
+    variables.put(variable.getName(), variable);
+  }
+
+  @Override
+  public Map<String, Variable<?>> variables() {
+    return Collections.unmodifiableMap(variables);
+  }
+
   // Related native objects (such as the TF_Operation object backing an Operation instance)
   // have a validity tied to that of the Graph. The handles to those native objects are not
   // valid after Graph.close() has been invoked.

tensorflow-core/tensorflow-core-api/src/main/java/org/tensorflow/op/NameScope.java

@@ -45,7 +45,9 @@ NameScope withSubScope(String scopeName) {
   }
 
   NameScope withName(String name) {
-    checkPattern(NAME_REGEX, name);
+    if(name != null) {
+      checkPattern(NAME_REGEX, name);
+    }
     // All context except for the opName is shared with the new scope.
     return new NameScope(opPrefix, name, ids);
   }

tensorflow-core/tensorflow-core-api/src/main/java/org/tensorflow/op/Scope.java

@@ -117,7 +117,9 @@ public Scope withSubScope(String childScopeName) {
    *
    * <p>Names must match the regular expression {@code [A-Za-z0-9.][A-Za-z0-9_.\-]*}
    *
-   * @param opName name for an operator in the returned scope
+   * <p>{@code opName} may be null, which unsets the name.
+   *
+   * @param opName name for an operator in the returned scope.  May be null to unset name.
    * @return a new Scope that uses opName for operations.
    * @throws IllegalArgumentException if the name is invalid
    */

tensorflow-core/tensorflow-core-api/src/main/java/org/tensorflow/op/core/Helpers.java

@@ -42,8 +42,10 @@ private Helpers() {}
      * @param init The op to use to initialise this variable.
      * @param options carries optional attributes values
      * @return a new instance of Variable
+     * @deprecated Use {@link org.tensorflow.op.Ops#Variable(Operand)} instead for a tf.Variable like API.
      */
     @Endpoint(name = "variable")
+    @Deprecated
     public static <T extends TType> Variable<T> createVariableWithInit(Scope scope, Operand<T> init, Variable.Options... options) {
         Variable<T> newVar = Variable.create(scope, init.shape(), init.type(), options);
         Assign<T> assignOp = Assign.create(scope, newVar, init);