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| Class | Purpose |
|---|---|
| AbstractETLRowStep | Extend this class if the step is required to process data row by row and output data as and when it is processed. Filter and Calculated Field are examples of row steps. |
| AbstractETLCachedStep | This class should be extended if the step is required to accumulate data before it can begin processing. For example, Merge and Union are cached steps. |
| AbstractETLInlineRowStep | Inline transforms are expected to be row steps. Extend AbstractETLInlineRowStep to implement an inline transform. |
Types of Step Implementation
Depending on which abstract class is used different methods need to be implemented. There are some common aspects though. For ease of understanding, the implementation details are split into three sections:
- User Interface Implementation
- Processing Implementation
- Helper Methods.
User Interface Implementation
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- Step user interface implementation: Methods used to implement the step's UI
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public String getDefaultName()
Use this method to define the name of the step. This name will be displayed in the Step List (left panel) of the Transformation Flow Builder.
Example:
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@Override
public String getDefaultName() {
return "Append Number";
} |
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public String getDefaultDescription()
Define a description of the step. This will be displayed in the Step List (left panel) of the Transformation Flow Builder.
Example:
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@Override
public String getDefaultDescription() {
return "Append a number to the data in a field";
} |
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public ETLStepCategory getStepCategory()
Specify which category the step should appear under. Available categories are listed in enum ETLStepCategory.
Example:
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@Override
public ETLStepCategory getStepCategory() {
return ETLStepCategory.TRANSFORM;
} |
- .
- Processing implementation: Methods used to define the step's processing logic.
- Helper methods: Additional methods involved in implementing a step. These include:
- Input/Output methods: Handles a step's input and output flow.
- Field methods: Deals with a step's default or output metadata fields.
- Configuration methods: Methods that configure a step's options.
- Data processing methods: Methods used to manipulate data during a step's execution.
- Error handling methods: These are used to handle errors.
- Other methods: Some additional methods that might be of interest in step implementation.
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