public class GraphNode {
    public final Stage<?> stage;
    public final TableId[] estimatorInputs;
    public final TableId[] modelInputs;
    public final TableId[] outputs;
}

/**
 * A Graph acts as an Estimator. A Graph consists of a DAG of stages, each of which could be an
 * Estimator, Model, Transformer or AlgoOperator. When `Graph::fit` is called, the stages are
 * executed in a topologically-sorted order. If a stage is an Estimator, its `Estimator::fit` method
 * will be called on the input tables (from the input edges) to fit a Model. Then the Model will be
 * used to transform the input tables and produce output tables to the output edges. If a stage is
 * an AlgoOperator, its `AlgoOperator::transform` method will be called on the input tables and
 * produce output tables to the output edges. The GraphModel fitted from a Graph consists of the
 * fitted Models and AlgoOperators, corresponding to the Graph's stages.
 */
@PublicEvolving
public final class Graph implements Estimator<Graph, GraphModel> {
    public Graph(List<GraphNode> nodes, TableId[] estimatorInputIds, TableId[] modelInputs, TableId[] outputs, TableId[] inputModelData, TableId[] outputModelData) {...}

    @Override
    public GraphModel fit(Table... inputs) {...}

    @Override
    public void save(String path) throws IOException/**
 * A Graph acts as an Estimator. A Graph consists of a DAG of stages, each of which could be an
 * Estimator, Model, Transformer or AlgoOperator. When `Graph::fit` is called, the stages are
 * executed in a topologically-sorted order. If a stage is an Estimator, its `Estimator::fit` method
 * will be called on the input tables (from the input edges) to fit a Model. Then the Model will be
 * used to transform the input tables and produce output tables to the output edges. If a stage is
 * an AlgoOperator, its `AlgoOperator::transform` method will be called on the input tables and
 * produce output tables to the output edges. The GraphModel fitted from a Graph consists of the
 * fitted Models and AlgoOperators, corresponding to the Graph's stages.
 */
@PublicEvolving
public final class Graph implements Estimator<Graph, GraphModel> {
    public Graph(List<GraphNode> nodes, TableId[] estimatorInputIds, TableId[] modelInputs, TableId[] outputs, TableId[] inputModelData, TableId[] outputModelData) {...}

    @Override
    public GraphModel fit(Table... inputs) {...}

    @Override
    public void save(String path) throws IOException {...}

    @Override
    public static Graph load(String path) throws IOException {...}
}

/**
 * A GraphModel acts as a Model. A GraphModel consists of a DAG of stages, each of which could be a
 * Model, Transformer or AlgoOperators. When `GraphModel::transform` is called, the stages are
 * executed in a topologically-sorted order. When a stage is executed, its `AlgoOperator::transform`
 * method will be called on the input tables (from the input edges) and produce output tables to the
 * output edges.
 */
public final class GraphModel implements Model<GraphModel> {

    public GraphModel(List<GraphNode> nodes, TableId[] inputIds, TableId[] outputIds, TableId[] inputModelData, TableId[] outputModelData) {...}

    @Override
    public Table[] transform(Table... inputTables) {...}

    @Override
    public void setModelData(Table... inputs) {...}

    @Override
    public Table[] getModelData() {...}

    @Override
    public void save(String path) throws IOException {...}

    public static GraphModel load(String path) throws IOException {...}
}


/**
 * A GraphBuilder provides APIs to build Graph/Model/AlgoOperator from a DAG of stages, each of
 * which could be an Estimator, Model, Transformer or AlgoOperator.
 */
@PublicEvolvingstatic Graph load(String path) throws IOException {...}
}

/**
 * A GraphModel acts as a Model. A GraphModel consists of a DAG of stages, each of which could be an
 * Estimator, Model, Transformer or AlgoOperators. When `GraphModel::transform` is called, the
 * stages are executed in a topologically-sorted order. When a stage is executed, its
 * `AlgoOperator::transform` method will be called on the input tables (from the input edges) and
 * produce output tables to the output edges.
 */
public final class GraphBuilderGraphModel implements Model<GraphModel> {

    public private int maxOutputLength = 20;

    public GraphBuilder() {GraphModel(List<GraphNode> nodes, TableId[] inputIds, TableId[] outputIds, TableId[] inputModelData, TableId[] outputModelData) {...}

    /**@Override
    public * Specifies the upper bound (could be loose) of the number of output tables that can be
     * returned by the Transformer::getModelData and AlgoOperator::transform methods, for any stageTable[] transform(Table... inputTables) {...}

    @Override
    public void setModelData(Table... inputs) {...}

    @Override
    public * involved in this Graph.
Table[] getModelData() {...}

     *@Override
     * <p>The default upper bound ispublic 20.
     */void save(String path) throws IOException {...}

    public static GraphBuilderGraphModel setMaxOutputLengthload(intString maxOutputLengthpath) throws IOException {...}
}

/**
 * A GraphBuilder provides APIs to build /**
     * Creates a TableId associated with this GraphBuilder. It can be used to specify the passing ofEstimator/Model/AlgoOperator from a DAG of stages, each of
 * which could be an Estimator, Model, Transformer or AlgoOperator.
 */
@PublicEvolving
public final class GraphBuilder {
    private *int maxOutputLength tables between stages, as well as the input/output tables of the Graph/GraphModel generated= 20;

    public GraphBuilder() {}

    /**
     * bySpecifies thisthe builder.
upper bound (could be loose) */
of the number of publicoutput TableIdtables createTableId() {...}

    /**that can be
     * Ifreturned by the Transformer::getModelData stage is an Estimator, both its fit method and the transform method of its fittedand AlgoOperator::transform methods, for any stage
     * involved in this Graph.
     *
 Model would be invoked with* the<p>The givendefault inputsupper whenbound theis graph runs20.
     */
    public *GraphBuilder <p>If this stage is a Model, Transformer or AlgoOperator, its transform method would be
     * invoked with the given inputs when the graph runs.setMaxOutputLength(int maxOutputLength) {...}

    /**
     * Creates a TableId associated with this GraphBuilder. It can be used to specify the passing of
     *
 tables between stages, as *well as <p>Returnsthe ainput/output listtables of TableIds, which represents outputs of AlgoOperator::transform of the given stage the Graph/GraphModel generated
     * by this builder.
     */
    public TableId[] getOutputs(Stage<?> stage, TableId... inputscreateTableId() {...}

    /**
     * If thisthe stage is an Estimator, both its fit method would be invoked with estimatorInputs, and the
     * transform method of its fitted Model would be invoked with modelInputs.
     * transform method of its fitted
     * <p>ThisModel methodwould throwsbe Exceptioninvoked ifwith the given stageinputs iswhen notthe angraph Estimatorruns.
     *
     * <p>This<p>If this methodstage is usefula whenModel, theTransformer stateor isAlgoOperator, anits Estimatortransform ANDmethod the Estimator::fit needs to takewould be
     * a different list of Tables frominvoked with the Model::transform of given inputs when the fittedgraph Modelruns.
     *
     * <p>Returns a list of TableIds, which represents outputs of ModelAlgoOperator::transform of the fittedgiven Modelstage.
     */
    public TableId[] getOutputs(Stage<?> stage, TableId[] estimatorInputs, TableId[] modelInputs) {...}

    /**... inputs) {...}

    /**
     * If this stage is an Estimator, its fit method would be invoked with estimatorInputs, and the
     * Thetransform setModelData()method of theits fitted GraphModelModel shouldwould invokebe theinvoked setModelData() of the givenwith modelInputs.
     * stage with the given inputs.
     */
 <p>This method throws publicException void setModelData(Stage<?>if the stage, TableId... inputs) {...}

 is not an Estimator.
     /**
     * <p>This method Theis getModelData()useful ofwhen the fittedstate is GraphModelan shouldEstimator invokeAND the getModelData() of the given
     * stageEstimator::fit needs to take
     * a different list of Tables from the Model::transform of the fitted Model.
     *
     * <p>Returns a list of TableIds, which represents the outputs of getModelData()Model::transform of the given
     * stagefitted Model.
     */
    public TableId[] getModelDatagetOutputs(Stage<?> stage, TableId[] estimatorInputs, TableId[] modelInputs) {...}

    /**
     * Returns an Estimator instance with the following behavior:
     *
     * <p>1) Estimator::fit should take the given inputs and return a Model with the following The setModelData() of the fitted GraphModel should invoke the setModelData() of the given
     * behavior.
stage with the given  *inputs.
     */
 <p>2) Model::transform should takepublic the given inputs and return the given outputs.
void setModelData(Stage<?> stage, TableId... inputs) {...}

     /**
     * <p>The fit methodThe getModelData() of the fitted returnedGraphModel Estimatorshould andinvoke the transformgetModelData() method of the fitted Modelgiven
     * stage.
     *
 should    invoke* the<p>Returns correspondinga methodslist of TableIds, which represents the internaloutputs stagesof as specified bygetModelData() of the given
     * GraphBuilderstage.
     */
    public Estimator<?, ?> buildEstimator(TableId[] inputs, TableId[] outputsgetModelData(Stage<?> stage) {...}

    /**
     * Returns an Estimator instance with the following behavior:
     *
     * <p>1) Estimator::fit should take the given inputs and returns a Model with the following
     * behavior.:
     *
     * <p>2<p>1) ModelEstimator::transformfit should take the given inputs and return thea givenModel outputs.
with the    *following
     * <p>3) Model::setModelData should take the given inputModelDatabehavior.
     *
     * <p>4<p>2) Model::getModelDatatransform should take the given inputs and return the given outputModelDataoutputs.
     *
     * <p>The fit method of the returned Estimator and the transform/setModelData/getModelData
     * methods transform method of the fitted Model
     * should invoke the corresponding methods of the internal stages as
 specified by the
  * specified by the* GraphBuilder.
     */
    public Estimator<?, ?> buildEstimator(TableId[] inputs, TableId[] outputs, TableId[] inputModelData, TableId[] outputModelData) {...}



    /**
     * Returns an Estimator instance with the following behavior:
     *
     /**
     * Returns an Estimator instance* <p>1) Estimator::fit should take the given inputs and returns a Model with the following
 behavior:    * behavior.
     *
     * <p>1<p>2) EstimatorModel::fittransform should take the given estimatorInputsinputs and returns a Model with thereturn the given outputs.
     *
     * following behavior <p>3) Model::setModelData should take the given inputModelData.
     *
     * <p>2<p>4) Model::transformgetModelData should takereturn the given transformerInputsoutputModelData.
 and return the given outputs.*
     * <p>The fit method of the returned Estimator and the transform/setModelData/getModelData
     * <p>3)methods of the fitted Model::setModelData should takeinvoke the givencorresponding inputModelData.
methods of the internal stages *as
     * <p>4) Model::getModelData should return * specified by the given outputModelDataGraphBuilder.
     */
    public * <p>The fit method of the returned Estimator and the transform/setModelData/getModelDataEstimator<?, ?> buildEstimator(TableId[] inputs, TableId[] outputs, TableId[] inputModelData, TableId[] outputModelData) {...}

     /**
 methods of the fitted Model should* invokeReturns thean correspondingEstimator methodsinstance ofwith the internal stages asfollowing behavior:
     *
 specified by the GraphBuilder.
 * <p>1) Estimator::fit should */
take the given estimatorInputs publicand Estimator<?, ?> buildEstimator(TableId[] estimatorInputs, TableId[] modelInputs, TableId[] outputs, TableId[] inputModelData, TableId[] outputModelData) {...}

returns a Model with the
     * following behavior.
     /**
     * Returns an AlgoOperator instance with <p>2) Model::transform should take the given transformerInputs and return the followinggiven behavior:outputs.
     *
     * <p>1<p>3) AlgoOperatorModel::transformsetModelData should take the given inputs and returnsinputModelData.
     *
     * <p>4) Model::getModelData should return the given outputsoutputModelData.
     *
     * <p>The transformfit method of the returned AlgoOperator should invoke the corresponding methods
     * Estimator and the transform/setModelData/getModelData
     * methods of the fitted Model should invoke the corresponding methods of the internal stages as
     * specified by the GraphBuilder.
     */
    public Estimator<?, ?> buildEstimator(TableId[] estimatorInputs, TableId[] modelInputs, TableId[] public AlgoOperator<?> buildAlgoOperator(outputs, TableId[] inputsinputModelData, TableId[] outputsoutputModelData) {...}

    /**
     * Returns aan ModelAlgoOperator instance with the following behavior:
     *
     * <p>1) ModelAlgoOperator::transform should take the given inputs and returns the given outputs.
     *
     * <p>The transform method of the returned ModelAlgoOperator should invoke the corresponding methods
 of the
   * of *the internal stages as specified by the GraphBuilder.
     */
    public Model<AlgoOperator<?> buildModelbuildAlgoOperator(TableId[] inputs, TableId[] outputs) {...}

    /**
     * Returns a Model instance with the following behavior:
     *
     * <p>1) Model::transform should take the given inputs and returns the given outputs.
     *
     * <p>2) Model::setModelData should take the given inputModelData <p>The transform method of the returned Model should invoke the corresponding methods of the
     * internal stages as specified by the GraphBuilder.
     */
    public * <p>3) Model::getModelData should return the given outputModelData.
Model<?> buildModel(TableId[] inputs, TableId[] outputs) {...}

     /**
     * <p>The transform/setModelData/getModelData methods of the returned Model should invoke theReturns a Model instance with the following behavior:
     *
     * corresponding methods of <p>1) Model::transform should take the internalgiven stagesinputs asand specifiedreturns bythe thegiven GraphBuilderoutputs.
     */
    public Model<?> buildModel(TableId[] inputs, TableId[] outputs, TableId[] inputModelData, TableId[] outputModelData) {...}
}

public class GraphNode {
    public final Stage<?> stage;
    public final TableId[] estimatorInputs; * <p>2) Model::setModelData should take the given inputModelData.
     *
     * <p>3) Model::getModelData should return the given outputModelData.
    public final*
 TableId[] modelInputs;
   * public final TableId[] outputs;
}

public class TableId {
    private final int tableId;

    @Override
    public boolean equals(Object obj) {...}

    @Override<p>The transform/setModelData/getModelData methods of the returned Model should invoke the
     * corresponding methods of the internal stages as specified by the GraphBuilder.
     */
    public intModel<?> hashCode(buildModel(TableId[] inputs, TableId[] outputs, TableId[] inputModelData, TableId[] outputModelData) {...}
}