# Add External Java Class
ONEWEB allows you to extend application functionality by attaching **external Java classes** to an entity using **Entity Actions**.\
This mechanism enables developers to execute **custom server‑side logic** during entity processing events such as **INSERT**, **UPDATE**, or **DELETE**.
External Java classes are commonly used for:
* Complex business rules
* Data manipulation before persistence
* Integration with external systems
* Custom validation or processing logic
***
### Configure Class Action in App Designer
#### Step 1: Open Entity in App Designer
1. Open **App Designer**
2. Select and open the target **Entity**
***
#### Step 2: Add Entity Action
1. In the **Navigator pane**, go to\
**Tool → Action**
2. Drag the **Action** icon and drop it onto the entity
***
#### Step 3: Configure Module Action
Click the **Edit** icon to open **Module Action Field Configuration**.
Configure the following:
* **Process Name**: `UPDATE`
* **Class Action**:
```
com.training.manual.ApplicationManualClass
```
Click **OK** to save.
***
#### Step 4: Configure INSERT Process
Repeat the same steps for:
* **Process Name**: `INSERT`
***
#### Step 5: Save Configuration
Click **Save** to persist the Entity Action configuration.
***
### Create Java Class in Eclipse
#### Step 6: Create Java Class
1. Open **Eclipse IDE**
2. In **Project Explorer**, right‑click:
```
/MasterWeb/Java Sources/src
```
3. Select **New → Class**
4. Name the class:
```
ApplicationManualClass
```
5. Click **Finish**
***
#### Default Generated Class Structure
```
public class ApplicationManualClass
extends ProcessHelper
implements ProcessAction {
@Override
public Vector modifyResult() {
return null;
}
@Override
public boolean validateResult() {
return false;
}
}
```
**Method Purpose**
| Method | Description |
| ------------------ | ----------------------------------------------------- |
| `modifyResult()` | Modify submitted data before INSERT / UPDATE / DELETE |
| `validateResult()` | Validate submitted data before processing |
***
### Modify Java Class Logic
#### Example: Log Submitted Data and Button Action
```
public class ApplicationManualClass
extends ProcessHelper
implements ProcessAction {
@Override
public Vector modifyResult() {
Vector dataModels = getResultForProcess();
String buttonAction =
request.getParameter("SUBMIT_BUTTON");
System.out.println("Data Models: " + dataModels);
System.out.println("Button Action: " + buttonAction);
return dataModels;
}
@Override
public boolean validateResult() {
return true;
}
@Override
public HashMap modifyLoadUpdateResult() {
return super.modifyLoadUpdateResult();
}
}
```
***
### Deploy Java Class
#### Step 7: Publish to Server
1. Open the **Servers** view
2. Right‑click the server
3. Select **Publish**
4. Wait until server status becomes **Synchronized**
***
### Test the Java Class
#### Step 8: Run Application
1. Open:
```
http://:8080/FrontWeb
```
2. Log in to the application
3. Open **Create Application**
4. Click **Add**
5. Enter application data
6. Click **Submit**
***
#### Verify Execution Output
In **Eclipse → Console**, the output log should display submitted data and button action.
***
### Summary
Adding an **External Java Class** in ONEWEB enables powerful server‑side customization.
Key capabilities include:
* Executing Java code during entity operations
* Modifying data before persistence
* Enforcing business rules
* Integrating with external systems
* Logging and debugging runtime behavior
By leveraging **Entity Actions + Java Classes**, developers can extend Smart Forms far beyond default behavior while maintaining control, security, and scalability.
---
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