/**
 * 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

/**
 * A Graph acts as an Estimator. A Graph consists of a DAG of stages, each of which could be
 * an Estimator, 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, which is a
 * Transformer, will be used to transform the input tables to produce output tables to the output
 * edges. If a stage is a Transformer or AlgoOperator, its `AlgoOperator::transform`
 * method will be called on the
 * input tables (from the input tablesedges) toand produce output tables to the
 * output edges.
 The fitted model from a Graph is a
 * GraphTransformer, which consists of fitted models and transformers, corresponding to the Graph's
 * stages.
 */
@PublicEvolving
public final class Graph implements Estimator<Graph, GraphTransformer> {*/
public final class GraphModel implements Model<GraphModel> {

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

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

    @Override
    public GraphTransformervoid fitsetModelData(Table... inputs) {...}

    /** Skipped a few methods, including the implementations of some Estimator APIs. */
}

/**
 * A GraphTransformer acts as a Transformer. A GraphTransformer consists of a DAG of Transformers or AlgoOperators. When
 * `GraphTransformer::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) to produce output tables to the output edges.
 */
public final class GraphTransformer implements Transformer<GraphTransformer> {
    /** Skipped a few methods, including the implementations of the Transformer APIs. */
}

/**
 * A GraphBuilder provides APIs to build Graph and GraphTransformer from a DAG of Estimator, Transformer and
 * AlgoOperator instances.
 */
@PublicEvolving
public final class GraphBuilder {
    private int maxOutputLength = 20;
@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.
 */
@PublicEvolving
public final class GraphBuilder {
    private int maxOutputLength = 20;

    public GraphBuilder() {}

    /**
     * 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 stage
     * involved in this Graph.
     *
     * <p>The default upper bound is 20.
     */
    public GraphBuilder setMaxOutputLength(int maxOutputLength) {...}

    /**
     /**
 Specifies the upper bound (could* beCreates loose)a ofTableId theassociated numberwith ofthis outputGraphBuilder. tablesIt that can be
 used to   * returned by specify the Transformer::getStateStreams and Transformer::transform methods, for any
     * stage involved in this Graph.
     *passing of
     * tables between stages, as well as the input/output tables of the Graph/GraphModel generated
     * <p>Theby default upper bound is 20this builder.
     */
    public GraphBuilderTableId setMaxOutputLengthcreateTableId(int maxOutputLength) {...}

    /**
     * Creates a TableId associated with this GraphBuilder. It can be used to specify the passing of/**
     * tables between stages, as well as the input/output tables of the Graph/GraphTransformer generated If the stage is an Estimator, both its fit method and the transform method of its fitted
     * byModel thiswould builder.
be invoked with the given */
inputs when the  public TableId createTableId() {...}

graph runs.
     /**
     * If<p>If thethis stage is ana EstimatorModel, both Transformer or AlgoOperator, its fittransform method and the transform method of its fitted would be
     * invoked with the given inputs when the graph runs.
     *
     * <p>Returns a Transformerlist wouldof beTableIds, invokedwhich withrepresents theoutputs given inputs whenof AlgoOperator::transform of the graphgiven runsstage.
     */
    public * <p>If this stage is a Transformer or AlgoOperator, its transform method would be invoked with the given
     * inputs when the graph runs.
     *TableId[] getOutputs(Stage<?> stage, TableId... inputs) {...}

    /**
     * If this stage is an Estimator, its fit method would be invoked with estimatorInputs, and the
     * <p>Returnstransform amethod listof ofits TableIds,fitted whichModel representswould outputsbe ofinvoked the Transformer::transformwith modelInputs.
     * invocation.
     */
 <p>This method throws publicException TableId[] getOutputs(Stage<?>if the stage, TableId... inputs) {...}

 is not an Estimator.
     /**
     * If this stage <p>This method is useful when the state is an Estimator, AND itsthe Estimator::fit method would be invoked with estimatorInputs, and the needs to take
     * a different list of Tables from the Model::transform of the fitted Model.
     *
 transform method of its fitted* Transformer<p>Returns woulda belist invokedof with transformerInputsTableIds, whenwhich the
represents outputs of Model::transform of *the graphfitted runsModel.
     */
    public * <p>This method throws Exception if the stage is a Transformer or AlgoOperator.TableId[] getOutputs(Stage<?> stage, TableId[] estimatorInputs, TableId[] modelInputs) {...}

     /**
     * <p>ThisThe method is useful when setModelData() of the statefitted isGraphModel anshould Estimatorinvoke AND the Estimator::fit needs to takesetModelData() of the given
     * a different list of Tables from the Transformer::transform ofstage with the fittedgiven Transformerinputs.
     */
    public * <p>Returns a list of TableIds, which represents outputs of the Transformer::transformvoid setModelData(Stage<?> stage, TableId... inputs) {...}

    /**
     * invocation.
     */
    public TableId[] getOutputs(Stage<?> stage, TableId[] estimatorInputs, TableId[] transformerInputs) {...}

    /* The getModelData() of the fitted GraphModel should invoke the getModelData() of the given
     * stage.
     *
     * The GraphTransformer::setStateStreams should invoke the setStateStreams method <p>Returns a list of TableIds, which represents the outputs of getModelData() of the stage withgiven
     * the given inputsstage.
     */
    public voidTableId[] setStateStreamsgetModelData(Stage<?> stage, TableId... inputs) {...}

    /**
     * Returns The GraphTransformer::getStateStreams should invokean Estimator instance with the getStateStreams method of the stage.following behavior:
     *
     *
 <p>1) Estimator::fit should take *the <p>Returnsgiven ainputs listand ofreturn TableIds,a whichModel representswith the outputsfollowing
  of getStateStreams of the* stagebehavior.
     */
    TableId[] getStateStreams(Stage<?> stage) {...}

 * <p>2) Model::transform should take the given inputs and return the given outputs.
     /**
     * Returns<p>The fit anmethod Estimatorof instancethe whichreturned theEstimator followingand APIthe specification:
transform method of the fitted *Model
     * <p>1) Estimator::fit should take inputs and returns a Transformer with the following should invoke the corresponding methods of the internal stages as specified by the
     * specificationGraphBuilder.
     */
    public * <p>2) Transformer::transform should take inputs and return outputs.
Estimator<?, ?> buildEstimator(TableId[] inputs, TableId[] outputs) {...}

     /**
     * Returns <p>Thean fit/transformEstimator shouldinstance invokewith the APIs of the internal stages in the order specified by the DAG of stages.
     */
    Estimator buildEstimator(TableId[] inputs, TableId[] outputs) {...}

    /* following behavior:
     *
     * <p>1) Estimator::fit should take the given inputs and returns a Model with the following
     * behavior.
     *
     * Returns an Estimator instance which <p>2) Model::transform should take the given inputs and return the following API specification:given outputs.
     *
     * <p>1<p>3) EstimatorModel::fit should take inputs and returns a Transformer with the following specificationsetModelData should take the given inputModelData.
     *
     * <p>4) Model::getModelData should return the given outputModelData.
     *
     * <p>2) Transformer::transform should take inputs <p>The fit method of the returned Estimator and return outputs.the transform/setModelData/getModelData
     *
 methods of the fitted *Model <p>3) Transformer::setStateStreams should take inputStates.
     *should invoke the corresponding methods of the internal stages as
     * <p>4) Transformer::getStateStreams should return outputStatesspecified by the GraphBuilder.
     */
    public Estimator<?, ?> buildEstimator(TableId[] inputs, TableId[] * <p>The fit/transform/setStateStreams/getStateStreams should invoke the APIs of the internaloutputs, TableId[] inputModelData, TableId[] outputModelData) {...}

    /**
     * stages in Returns an Estimator instance with the orderfollowing specifiedbehavior:
 by the DAG of stages.*
     */
    Estimator buildEstimator(TableId[] inputs, TableId[] outputs, TableId[] inputStates, TableId[] outputStates) {...}

    /** <p>1) Estimator::fit should take the given estimatorInputs and returns a Model with the
     * following behavior.
     *
     * Returns an Estimator instance which <p>2) Model::transform should take the given transformerInputs and return the following API specification:given outputs.
     *
     * <p>1<p>3) EstimatorModel::fitsetModelData should take estimatorInputs and returns a Transformer with the followinggiven specificationinputModelData.
     *
     * <p>2<p>4) TransformerModel::transformgetModelData should takereturn transformerInputsthe andgiven return outputsoutputModelData.
     *
     * <p>3) Transformer::setStateStreams should take inputStates.
     *<p>The fit method of the returned Estimator and the transform/setModelData/getModelData
     * <p>4) Transformer::getStateStreams methods of the fitted Model should return outputStates.
     *invoke the corresponding methods of the internal stages as
     * <p>The fit/transform/setStateStreams/getStateStreams should invoke the APIs of the internal
     * stages in the order specified by the DAG of stages.
     specified by the GraphBuilder.
     */
    public Estimator<?, ?> buildEstimator(TableId[] estimatorInputs, TableId[] modelInputs, TableId[] outputs, TableId[] inputModelData, TableId[] outputModelData) {...}

    /**
     * <p>ThisReturns methodan isAlgoOperator usefulinstance whenwith the following Estimator::fit needs to take a different list of Tables frombehavior:
     *
     * the<p>1) TransformerAlgoOperator::transform should oftake the fittedgiven Transformer.
inputs and returns   */
    Estimator buildEstimator(
    the given outputs.
     *
   TableId[] estimatorInputs,
 * <p>The transform method of the returned AlgoOperator should invoke the TableId[] transformerInputs,corresponding methods
     * of the internal stages as specified by TableId[] outputs,the GraphBuilder.
     */
    public AlgoOperator<?>  buildAlgoOperator(TableId[] inputStates,
            inputs, TableId[] outputStatesoutputs) {...}

    /**
     * Returns a TransformerModel instance whichwith the following API specificationbehavior:
     *
     * <p>1) TransformerModel::transform should take the given inputs and returns outputs.
     *
     * <p>2) Transformer::setStateStreams should take inputStates.
     *
     * <p>3) Transformer::getStateStreams should return outputStatesthe given outputs.
     *
     * <p>The fit/transform/setStateStreams/getStateStreamstransform method of the returned Model should invoke the corresponding APIsmethods of the
     * internal stages as specified by the GraphBuilder.
     */
 stages in the orderpublic specified by the DAG of stages.
Model<?> buildModel(TableId[] inputs, TableId[] outputs) {...}

     /**
     * <p>ThisReturns methoda throwsModel Exceptioninstance ifwith anythe stagefollowing ofbehavior:
 this DAG is an Estimator.*
     */
    Transformer buildTransformer(TableId[] inputs, TableId[] outputs, TableId[] inputStates, TableId[] outputStates) {...}

    /* <p>1) Model::transform should take the given inputs and returns the given outputs.
     *
     * Returns an AlgoOperator instance which the following API specification:<p>2) Model::setModelData should take the given inputModelData.
     *
     * <p>1<p>3) AlgoOperatorModel::transformgetModelData should takereturn inputsthe andgiven returns outputsoutputModelData.
     *
     * <p>The fit/transform should invoke the APIstransform/setModelData/getModelData methods of the returned Model should invoke the
     * corresponding methods of the internal stages in theas order specified by the DAG of stagesGraphBuilder.
     */
    public Model<?> buildModel(TableId[] inputs, TableId[] outputs, TableId[] inputModelData, TableId[] outputModelData) {...}
}

public class GraphNode *{
 <p>This method throws Exceptionpublic iffinal anyStage<?> stage;
 of  this DAGpublic isfinal an Estimator.TableId[] estimatorInputs;
     */public final TableId[] modelInputs;
    AlgoOperatorpublic final buildAlgoOperator(TableId[] inputs,outputs;
}

public class TableId[] outputs) {...}

    private //final The TableId is necessary to pass the inputs/outputs of various API calls across theint tableId;

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

    // Graph/GraphTransformer stages.@Override
    staticpublic classint TableIdhashCode() {...}
}