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Data Exchange Add-on Documentation > User Guide > Advanced Data Exchange Options > Using a custom transformation
Navigation modeData Exchange Add-on Documentation > User Guide > Advanced Data Exchange Options > Using a custom transformation

Implementing a custom transformation

Overview

This section shows how to implement a basic transformation function for the EBX Data Exchange Add-on. This type of implementation requires the following:

Transformation definition class

The following code sample shows a definition class for an add-on transformation function:

public class NumToWeekdayTransformationDefinition implements TransformationDefinition
{
 
    public String getCode()
    {
        return "numToweekday";
    }
 
    public UserMessage getLabel()
    {
        return UserMessage.createInfo("Num to Weekday transformation Function");
    }
 
    public UserMessage getDescription()
    {
        return UserMessage.createInfo(
            "On import a number in the source is converted to its corresponding day of the week.");
    }
 
    public List<InputDefinition> getInputDefinitions()
    {
        List<InputDefinition> inputDefinitions = new ArrayList<InputDefinition>();
        inputDefinitions.add(
            new InputDefinition(
                "String Input",
                UserMessage.createInfo("Input is a String"),
                SchemaTypeName.XS_STRING,
                false));
        return inputDefinitions;
    }
 
    public OutputDefinition getOutputDefinition()
    {
        return new OutputDefinition(
            UserMessage.createInfo("A day of the week"),
            SchemaTypeName.XS_STRING,
            false);
    }
 
    public List<ParameterDefinition> getParameterDefinitions()
    {
        return new ArrayList<ParameterDefinition>();
    }
 
    //You can use this transformation definition to automatically detect the file type. Based on the type, it can return a different transformation.
    public Transformation getTransformation(ServiceType serviceType)
    {
        switch (serviceType)
        {
        case SPREADSHEET_IMPORT:
            return new ConvertNumToWeekday();
        case CSV_IMPORT:
            //Add your own transformation for CSV or other formats.
        default:
            return null;
        }
    }
 
    public boolean isBidirectional()
    {
        return false;
    }
 
    public boolean isAggregation()
    {
        return false;
    }
 
}

Note that as shown in the image, the methods shown above return values used by the add-on to define a transformation configuration.

/wkday-code-sample.png

Transformation implementation

The following code sample shows an implementation of a transformation that takes a numeric value in the source and outputs the value's corresponding day of the week in the target:

public class ConvertNumToWeekday implements Transformation<ImportTransformationExecutionContext>
{
    private Locale locale;
    public void setup(TransformationConfigurationContext configurationContext)
        throws DataExchangeException
    {
        if (configurationContext == null)
        {
            throw new DataExchangeException(UserMessage.createError("Context is not initialized."));
        }
        this.locale = configurationContext.getSession().getLocale();
    }
 
    //This method gets the input data to transform and defines the transformation logic.
    public Object execute(ImportTransformationExecutionContext executionContext)
        throws DataExchangeException
    {
        if (executionContext == null)
        {
            throw new DataExchangeException(UserMessage.createError("Context is not initialized."));
        }
 
        //Obtain the value to import from the source application.
        Object inputValue = executionContext.getInputValue();
        if (inputValue == null)
        {
            return null;
        }
 
        //Performs a check on the target location.
        SchemaNode schemaNode = null;
        if (EBXField.class.isInstance(executionContext.getTargetField()))
        {
            EBXField ebxField = (EBXField) executionContext.getTargetField();
            schemaNode = ebxField.getSchemaNode();
 
            if (schemaNode.isComplex())
            {
                throw new DataExchangeException(
                    UserMessage.createError(
                        schemaNode.getLabel(this.locale)
                            + " is a complex type node. The transformation function 'Convert an integer to a string and vice versa' only supports simple type node."));
            }
        }
 
        //Sets how the data is transformed. In this case it is from one value to another. You could also specify that data types be transformed, values concatenated, etc.
        try
        {
            switch (schemaNode.formatToXsString(inputValue))
            {
 
            case "1":
                return "Monday";
            case "2":
                return "Tuesday";
            case "3":
                return "Wednesday";
            case "4":
                return "Thursday";
            case "5":
                return "Friday";
            case "6":
                return "Saturday";
            case "7":
                return "Sunday";
            }
 
            throw new DataExchangeException(UserMessage.createError("Invalid input data."));
        }
        catch (ClassCastException ex)
        {
            throw new DataExchangeException(ex);
        }
        catch (ConversionException ex)
        {
            throw new DataExchangeException(ex);
        }
        catch (Exception ex)
        {
            throw new DataExchangeException(ex);
        }
    }
}

See Deploying and Adding to the add-on's catalog for instructions on the next steps.