User Defined Function/Operation () in HGrid247-3.5 is used to create custom data processing functions that are not available in standard operators.

This function is used in the UDF Function/Operation assembly to process each data record that enters the workflow.

To create a UDF in HGrid247, we have to create a Java class which is a subclass of the abstract class :

    com.solusi247.function.Function247

This class provides several methods used in data processing.

Methods in Function247

Class Function247has several important methods that must be understood.

1. public abstract void operate(List<Comparable> record)
   This method is the main method that is called for each data record received.
   Parameter:
   • record→ list of fields of the data record being processed
   Function:
   • perform data transformation or manipulation
   • generate output records
2. public String getParameter()
   This method is used to retrieve parameters given to a UDF .
   Usually used for:
   • function configuration
   • determine processing logic
3. public void prepare()
   This method is called after the UDF object is created .
   Usually used for:
   • variable initialization
   • open connection
   • read initial configuration
4. public void cleanup()
   This method is called after all records have been processed .
   Usually used for:
   • close the connection
   • clean up resources
5. public final void addToOutputCollector(List<Comparable> record)
   This method is used to send the processing result record to the workflow output .
6. public List<String> getIncomingFields()
   This method is used to get a list of field names from an input record .

Example UDF Function (Reverse)

The following is an example of a UDF implementation used to reverse text in a specific field .

    package plugins.function;

    import com.solusi247.function.Function247;
    import java.util.ArrayList;
    import java.util.List;


    public class Reverse extends Function247{

        @Override
        public void operate(List<Comparable> list) {

            ArrayList<Comparable> list_out=new ArrayList<>();
            for (int i=0; i<list.size(); i++){
                if (i==5){
                    StringBuilder sb=new StringBuilder(list.get(i).toString());
                    list_out.add(sb.reverse().toString());
                }else{
                    list_out.add(list.get(i));
                }
            }        
            this.addToOutputCollector(list_out);   
        }   
    }

Explanation of the Example

The above program performs the following processes:

1. Receive input records in the form ofList<Comparable>
2. Create a new output list
3. Iterate over each field
4. If the field index = 5 , then the field value is reversed using:

       StringBuilder.reverse()
           

Example:

    Input : "Jakarta" 
    Output : "atrakaJ"

Other fields remain the same
Output records are sent using:

    addToOutputCollector()

Compile and Deploy UDF

To make the UDF function appear in the HGrid247 GUI , do the following steps.

1. Compile Java Class
   Compile the class using the HGrid247 library:

       javac -cp HGrid247CommonLib-3.5.jar Reverse.java 
   

2. Create JAR File
   Create a jar file:

       jar cvf reverse-plugin.jar plugins/function/Reverse.class 
   

3. Copy JAR to Plugins Folder
   Simple file jar ke folder:

       HGrid247-3.5/plugins
   

4. Restart HGrid247
   After restart, the Reverse function will appear on:

   UDF Function / Operation Assembly
   

   
   
   
   

Example Use Case

Example of using Reverse UDF:
Input Dataset

    id,name,age,city,salary,comment
    1,Andi,25,Jakarta,5000,HelloWorld

Workflow

    HFS Source
          ↓
    UDF Function (Reverse)
          ↓
    HFS Sink

Output Dataset

1, Andi, 25, Jakarta, 5000, dlroWolleH

Advantages of UDF Function

Using UDFs provides several advantages:

1. Custom Data Processing
   Allows to create own processing logic.
2. Flexible Transformation
   Can perform complex data transformations.
3. Reusable Components
   Functions can be reused in multiple workflows.
4. Extend HGrid247 Capability
   Extends HGrid247 processing capabilities beyond the standard operators.