classDiagram
    class ProcessingStep~I, O~ {
        +process(input: I): O
    }

    class InitializeProcessorStep {
        +process(importRows: List<BrAPIImport>): List<BrAPIImport>
    }

    class GetExistingBrAPIDataStep {
        -program: Program
        +GetExistingBrAPIDataStep(program: Program)
        +process(importRows: List<BrAPIImport>): Map<String, PendingImportObject<?>>
    }

    class ProcessedData {
        -newData: Map<String, PendingImportObject<?>>
        -validationErrors: ValidationErrors
        -statistics: Map<String, ImportPreviewStatistics>
    }

    class Pipeline~I, O~ {
        -steps: List<ProcessingStep<?, ?>>
        -observers: List<PipelineObserver>
        +addStep<T>(step: ProcessingStep<T, ?>): void
        +addObserver(observer: PipelineObserver): void
        +execute(input: I): O
    }

       class ImportContext {
        -upload: ImportUpload
        -importRows: List<BrAPIImport>
        -mappedBrAPIImport: Map<Integer, PendingImport>
        -data: Table
        -program: Program
        -user: User
        -commit: boolean
    }

    class ExperimentProcessor {
        +ExperimentProcessor()
        +process(context: ImportContext): Map<String, ImportPreviewStatistics>
    }

    class Workflow {
        <<interface>>
        +process(input: ImportContext): ProcessedData
    }

    class ExperimentWorkflowFactory {
        +getWorkflow(context: ImportContext): Workflow
    }

    class CreateNewExperimentWorkflow {
        -pipeline: Pipeline<ImportContext, ProcessedData>
        +CreateNewExperimentWorkflow()
        +process(input: ImportContext): ProcessedData
    }

    class AppendOverwritePhenotypesWorkflow {
        -pipeline: Pipeline<ImportContext, ProcessedData>
        +AppendOverwritePhenotypesWorkflow()
        +process(input: ImportContext): ProcessedData
    }

    class PipelineObserver {
        <<interface>>
        +onStepStart(step: ProcessingStep<?, ?>, input: any): void
        +onStepEnd(step: ProcessingStep<?, ?>, output: any): void
        +onPipelineStart(input: any): void
        +onPipelineEnd(output: any): void
    }

    class StatusReportingPipelineObserver {
        -stepStartMessages: Map<Class<? extends ProcessingStep>, String>
        -stepEndMessages: Map<Class<? extends ProcessingStep>, String>
        -pipelineStartMessage: String
        -pipelineEndMessage: String
        +StatusReportingPipelineObserver(stepStartMessages: Map<Class<? extends ProcessingStep>, String>, stepEndMessages: Map<Class<? extends ProcessingStep>, String>, pipelineStartMessage: String, pipelineEndMessage: String)
        +onStepStart(step: ProcessingStep<?, ?>, input: any): void
        +onStepEnd(step: ProcessingStep<?, ?>, output: any): void
        +onPipelineStart(input: any): void
        +onPipelineEnd(output: any): void
    }

    ProcessingStep <|.. InitializeProcessorStep
    ProcessingStep <|.. GetExistingBrAPIDataStep

    Pipeline "1" *-- "many" ProcessingStep
    Pipeline "1" o-- "many" PipelineObserver

    ExperimentProcessor "1" o-- "1" Workflow

    ExperimentProcessor ..> ExperimentWorkflowFactory : uses
    ExperimentProcessor ..> ImportContext : uses

    Workflow <|.. AppendOverwritePhenotypesWorkflow
    Workflow <|.. CreateNewExperimentWorkflow
    Workflow ..> ProcessedData : uses

    CreateNewExperimentWorkflow "1" *-- "1" Pipeline
    AppendOverwritePhenotypesWorkflow "1" *-- "1" Pipeline

    PipelineObserver <|.. StatusReportingPipelineObserver

    ExperimentWorkflowFactory ..> Workflow : creates