How to develop a JDBC Options Binder

1. What is the problem?

2. How to solve the problem?

3. What is the input needed for your plugin?

1. Datasource: Use a custom datasource or Joget default datasource.
2. Custom JDBC Driver: The JDBC driver for custom datasource.
3. Custom JDBC URL: The JDBC connection URL for custom datasource.
4. Custom JDBC Username: The username for custom datasource.
5. Custom JDBC Password: The password for custom datasource.
6. SQL Query: The query to populate options.
7. Use Ajax: A checkbox to decide whether or not it is using AJAX to load options. (For AJAX Cascading Drop-Down List).

The query should also support a syntax to inject dependency values when using AJAX.

1. SELECT id, name from app_fd_sample where group = ?
2. SELECT id, name from app_fd_sample where group in (?)

4. What is the output and expected outcome of your plugin?

5. Are there any resources/API that can be reused?

You can refer to the implementation of other available Form Options Binder plugins. Joget default datasource can be retrieved with AppUtil.getApplicationContext().getBean("setupDataSource").

6. Prepare your development environment

You always need to have your Joget DX Source Code ready and built by following this guideline. 

The following tutorial is prepared with a Macbook Pro and Joget Source Code version 8.0-Snapshot. Please refer to the Guideline for developing a plugin article for other platform commands. 

Let's say your folder directory is as follows. 

- Home
  - joget
    - plugins
    - jw-community

The plugins directory is the folder you will create and store all your plugins and the jw-community directory is where the Joget DX Source code is stored.

Run the following command to create a Apache Maven project in pthe lugins directory. 

cd joget/plugins/
~/joget/jw-community/wflow-plugin-archetype/create-plugin.sh org.joget.tutorial jdbc_options_binder 8.0-Snapshot

Then, the shell script will ask you to key in a version number for the plugin and request a confirmation before generating the Apache Maven project. 

Define value for property 'version':  1.0-SNAPSHOT: : 8.0-Snapshot
[INFO] Using property: package = org.joget.tutorial
Confirm properties configuration:
groupId: org.joget.tutorial
artifactId: jdbc_options_binder
version: 5.0.0
package: org.joget.tutorial
Y: : y

We should get the "BUILD SUCCESS" message shown in your terminal and a jdbc_options_binder folder created in plugithe ns folder.

Open the Apache Maven project with your IDE of choice. In this tutorial, NetBeans is used.

7. Just code it! 

a. Extending the abstract class of a plugin type

Create a JdbcOptionsBinder class under the org.joget.tutorial package. Then, extend the class with org.joget.apps.form.model.FormBinder abstract class. 

To make it work as a Form Options Binder, you will need to implement org.joget.apps.form.model.FormLoadOptionsBinder interface. You would like to support the AJAX Cascading Drop-Down List as well, so you need to implement the org.joget.apps.form.model.FormAjaxOptionsBinder interface also. See to Form Options Binder Plugin.

b. Implement all the abstract methods

As usual, you have to implement all the abstract methods. You will use the AppPluginUtil.getMessage method to support i18n and use  the MESSAGE_PATH constant variable for the message resource bundle directory. 

package org.joget.tutorial;
  
import org.joget.apps.app.service.AppPluginUtil;
import org.joget.apps.app.service.AppUtil;
import org.joget.apps.form.model.Element;
import org.joget.apps.form.model.FormAjaxOptionsBinder;
import org.joget.apps.form.model.FormBinder;
import org.joget.apps.form.model.FormData;
import org.joget.apps.form.model.FormLoadOptionsBinder;
import org.joget.apps.form.model.FormRowSet;
  
public class JdbcOptionsBinder extends FormBinder implements FormLoadOptionsBinder, FormAjaxOptionsBinder {
     
    private final static String MESSAGE_PATH = "messages/JdbcOptionsBinder";
     
    public String getName() {
        return "JDBC Option Binder";
    }
  
    public String getVersion() {
        return "5.0.0";
    }
     
    public String getClassName() {
        return getClass().getName();
    }
  
    public String getLabel() {
        //support i18n
        return AppPluginUtil.getMessage("org.joget.tutorial.JdbcOptionsBinder.pluginLabel", getClassName(), MESSAGE_PATH);
    }
     
    public String getDescription() {
        //support i18n
        return AppPluginUtil.getMessage("org.joget.tutorial.JdbcOptionsBinder.pluginDesc", getClassName(), MESSAGE_PATH);
    }
  
    public String getPropertyOptions() {
        return AppUtil.readPluginResource(getClassName(), "/properties/jdbcOptionsBinder.json", null, true, MESSAGE_PATH);
    }
 
    public FormRowSet load(Element element, String primaryKey, FormData formData) {
        return loadAjaxOptions(null); // reuse loadAjaxOptions method
    }
  
    public boolean useAjax() {
        return "true".equalsIgnoreCase(getPropertyString("useAjax")); // let user to decide whether or not to use ajax for dependency field
    }
  
    public FormRowSet loadAjaxOptions(String[] dependencyValues) {
        throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
    }
}

In the properties definition options file, you will need to provide options as below. Please note that you will use the "@@message.key@@" syntax to support i18n in your properties options.

[{
    title : '@@form.jdbcOptionsBinder.config@@',
    properties : [{
        name : 'jdbcDatasource',
        label : '@@form.jdbcOptionsBinder.datasource@@',
        type : 'selectbox',
        options : [{
            value : 'custom',
            label : '@@form.jdbcOptionsBinder.customDatasource@@'
        },{
            value : 'default',
            label : '@@form.jdbcOptionsBinder.defaultDatasource@@'
        }],
        value : 'default'
    },{
        name : 'jdbcDriver',
        label : '@@form.jdbcOptionsBinder.driver@@',
        description : '@@form.jdbcOptionsBinder.driver.desc@@',
        type : 'textfield',
        value : 'com.mysql.jdbc.Driver',
        control_field: 'jdbcDatasource',
        control_value: 'custom',
        control_use_regex: 'false',
        required : 'true'
    },{
        name : 'jdbcUrl',
        label : '@@form.jdbcOptionsBinder.url@@',
        type : 'textfield',
        value : 'jdbc:mysql://localhost/jwdb?characterEncoding=UTF8',
        control_field: 'jdbcDatasource',
        control_value: 'custom',
        control_use_regex: 'false',
        required : 'true'
    },{
        name : 'jdbcUser',
        label : '@@form.jdbcOptionsBinder.username@@',
        type : 'textfield',
        control_field: 'jdbcDatasource',
        control_value: 'custom',
        control_use_regex: 'false',
        value : 'root',
        required : 'true'
    },{
        name : 'jdbcPassword',
        label : '@@form.jdbcOptionsBinder.password@@',
        type : 'password',
        control_field: 'jdbcDatasource',
        control_value: 'custom',
        control_use_regex: 'false',
        value : ''
    },{
        name : 'useAjax',
        label : '@@form.jdbcOptionsBinder.useAjax@@',
        type : 'checkbox',
        options : [{
            value : 'true',
            label : ''
        }]
    },{
        name : 'addEmpty',
        label : '@@form.jdbcOptionsBinder.addEmpty@@',
        type : 'checkbox',
        options : [{
            value : 'true',
            label : ''
        }]
    },{
        name : 'emptyLabel',
        label : '@@form.jdbcOptionsBinder.emptyLabel@@',
        type : 'textfield',
        control_field: 'addEmpty',
        control_value: 'true',
        control_use_regex: 'false',
        value : ''
    },{
        name : 'sql',
        label : '@@form.jdbcOptionsBinder.sql@@',
        description : '@@form.jdbcOptionsBinder.sql.desc@@',
        type : 'codeeditor',
        mode : 'sql',
        required : 'true'
    }],
    buttons : [{
        name : 'testConnection',   
        label : '@@form.jdbcOptionsBinder.testConnection@@',
        ajax_url : '[CONTEXT_PATH]/web/json/app[APP_PATH]/plugin/org.joget.tutorial.JdbcOptionsBinder/service?action=testConnection',
        fields : ['jdbcDriver', 'jdbcUrl', 'jdbcUser', 'jdbcPassword'],
        control_field: 'jdbcDatasource',
        control_value: 'custom',
        control_use_regex: 'false'
    }]
}]

In the Properties Options, you added a button for testing connection when using a custom datasource. This button will call a JSON API to do the test. So, your plugin will need to implement org.joget.plugin.base.PluginWebSupport interface to make it a Web Service Plugin as well. Let's implement the webService method as follows, to test the JDBC connection.

/**
 * JSON API for test connection button
 * @param request
 * @param response
 * @throws ServletException
 * @throws IOException
 */
public void webService(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    //Limit the API for admin usage only
    boolean isAdmin = WorkflowUtil.isCurrentUserInRole(WorkflowUserManager.ROLE_ADMIN);
    if (!isAdmin) {
        response.sendError(HttpServletResponse.SC_UNAUTHORIZED);
        return;
    }
     
    String action = request.getParameter("action");
    if ("testConnection".equals(action)) {
        String message = "";
        Connection conn = null;
        try {
            AppDefinition appDef = AppUtil.getCurrentAppDefinition();
             
            String jdbcDriver = AppUtil.processHashVariable(request.getParameter("jdbcDriver"), null, null, null, appDef);
            String jdbcUrl = AppUtil.processHashVariable(request.getParameter("jdbcUrl"), null, null, null, appDef);
            String jdbcUser = AppUtil.processHashVariable(request.getParameter("jdbcUser"), null, null, null, appDef);
            String jdbcPassword = AppUtil.processHashVariable(SecurityUtil.decrypt(request.getParameter("jdbcPassword")), null, null, null, appDef);
             
            Properties dsProps = new Properties();
            dsProps.put("driverClassName", jdbcDriver);
            dsProps.put("url", jdbcUrl);
            dsProps.put("username", jdbcUser);
            dsProps.put("password", jdbcPassword);
            DataSource ds = BasicDataSourceFactory.createDataSource(dsProps);
             
            conn = ds.getConnection();
             
            message = AppPluginUtil.getMessage("form.jdbcOptionsBinder.connectionOk", getClassName(), MESSAGE_PATH);
        } catch (Exception e) {
            LogUtil.error(getClassName(), e, "Test Connection error");
            message = AppPluginUtil.getMessage("form.jdbcOptionsBinder.connectionFail", getClassName(), MESSAGE_PATH) + "\n"  + e.getMessage();
        } finally {
            try {
                if (conn != null && !conn.isClosed()) {
                    conn.close();
                }
            } catch (Exception e) {
                LogUtil.error(DynamicDataSourceManager.class.getName(), e, "");
            }
        }
        try {
            JSONObject jsonObject = new JSONObject();
            jsonObject.accumulate("message", message);
            jsonObject.write(response.getWriter());
        } catch (Exception e) {
            //ignore
        }
    } else {
        response.setStatus(HttpServletResponse.SC_NO_CONTENT);
    }
}

Once you are done with the properties option to collect input and the web service to test the connection, you can work on the main method of the plugin which is the loadAjaxOptions method.

public FormRowSet loadAjaxOptions(String[] dependencyValues) {
    FormRowSet rows = new FormRowSet();
    rows.setMultiRow(true);
     
    //add empty option based on setting
    if ("true".equals(getPropertyString("addEmpty"))) {
        FormRow empty = new FormRow();
        empty.setProperty(FormUtil.PROPERTY_LABEL, getPropertyString("emptyLabel"));
        empty.setProperty(FormUtil.PROPERTY_VALUE, "");
        rows.add(empty);
    }
     
    //Check the sql. If require dependency value and dependency value is not exist, return empty result.
    String sql = getPropertyString("sql");
    if ((dependencyValues == null || dependencyValues.length == 0) && sql.contains("?")) {
        return rows;
    }
     
    Connection con = null;
    PreparedStatement pstmt = null;
    ResultSet rs = null;
     
    try {
        DataSource ds = createDataSource();
        con = ds.getConnection();
         
        //support for multiple dependency values
        if (sql.contains("?") && dependencyValues != null && dependencyValues.length > 1) {
            String mark = "?";
            for (int i = 1; i < dependencyValues.length; i++) {
                mark += ", ?";
            }
            sql = sql.replace("?", mark);
        }
         
        pstmt = con.prepareStatement(sql);
         
        //set query parameters
        if (sql.contains("?") && dependencyValues != null && dependencyValues.length > 0) {
            for (int i = 0; i < dependencyValues.length; i++) {
                pstmt.setObject(i + 1, dependencyValues[i]);
            }
        }
         
        rs = pstmt.executeQuery();
        ResultSetMetaData rsmd = rs.getMetaData();
        int columnsNumber = rsmd.getColumnCount();
         
        // Set retrieved result to Form Row Set
        while (rs.next()) {
            FormRow row = new FormRow();
             
            String value = rs.getString(1);
            String label = rs.getString(2);
             
            row.setProperty(FormUtil.PROPERTY_VALUE, (value != null)?value:"");
            row.setProperty(FormUtil.PROPERTY_LABEL, (label != null)?label:"");
             
            if (columnsNumber > 2) {
                String grouping = rs.getString(3);
                row.setProperty(FormUtil.PROPERTY_GROUPING, grouping);
            }
             
            rows.add(row);
        }
    } catch (Exception e) {
        LogUtil.error(getClassName(), e, "");
    } finally {
        try {
            if (rs != null) {
                rs.close();
            }
            if (pstmt != null) {
                pstmt.close();
            }
            if (con != null) {
                con.close();
            }
        } catch (Exception e) {
            LogUtil.error(getClassName(), e, "");
        }
    }
     
    return rows;
}
 
/**
 * To creates data source based on setting
 * @return
 * @throws Exception
 */
protected DataSource createDataSource() throws Exception {
    DataSource ds = null;
    String datasource = getPropertyString("jdbcDatasource");
    if ("default".equals(datasource)) {
        // use current datasource
         ds = (DataSource)AppUtil.getApplicationContext().getBean("setupDataSource");
    } else {
        // use custom datasource
        Properties dsProps = new Properties();
        dsProps.put("driverClassName", getPropertyString("jdbcDriver"));
        dsProps.put("url", getPropertyString("jdbcUrl"));
        dsProps.put("username", getPropertyString("jdbcUser"));
        dsProps.put("password", getPropertyString("jdbcPassword"));
        ds = BasicDataSourceFactory.createDataSource(dsProps);
    }
    return ds;
}

c. Manage the dependency libraries of your plugin

Our plugin is using dbcp, javax.servlet.http.HttpServletRequest and javax.servlet.http.HttpServletResponse class, so you will need to add the jsp-api and commons-dbcp library to your POM file.

<!-- Change plugin specific dependencies here -->
<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>jsp-api</artifactId>
    <version>2.0</version>
</dependency>
<dependency>
    <groupId>commons-dbcp</groupId>
    <artifactId>commons-dbcp</artifactId>
    <version>1.3</version>
</dependency>
<!-- End change plugin specific dependencies here -->

d. Make your plugin internationalization (i18n) ready

We are using the i18n message key in the getLabel and getDescription method. You also used the i18n message key in your properties options definition as well. So, you will need to create a message resource bundle properties file for your plugin. Create a resources/messages directory under the jdbc_options_binder/src/main directory. Then, create a JdbcOptionsBinder.properties file in the folder. In the properties file, let's add all the message keys and labels as below.

org.joget.tutorial.JdbcOptionsBinder.pluginLabel=JDBC Binder
org.joget.tutorial.JdbcOptionsBinder.pluginDesc=Used to load field's options using JDBC
form.jdbcOptionsBinder.config=Configure JDBC Binder
form.jdbcOptionsBinder.datasource=Datasource
form.jdbcOptionsBinder.customDatasource=Custom Datasource
form.jdbcOptionsBinder.defaultDatasource=Default Datasource
form.jdbcOptionsBinder.driver=Custom JDBC Driver
form.jdbcOptionsBinder.driver.desc=Eg. com.mysql.jdbc.Driver (MySQL), oracle.jdbc.driver.OracleDriver (Oracle), com.microsoft.sqlserver.jdbc.SQLServerDriver (Microsoft SQL Server)
form.jdbcOptionsBinder.url=Custom JDBC URL
form.jdbcOptionsBinder.username=Custom JDBC Username
form.jdbcOptionsBinder.password=Custom JDBC Password
form.jdbcOptionsBinder.useAjax=Use AJAX for cascade options?
form.jdbcOptionsBinder.addEmpty=Add Empty Option?
form.jdbcOptionsBinder.emptyLabel=Empty Option Label
form.jdbcOptionsBinder.sql=SQL SELECT Query
form.jdbcOptionsBinder.sql.desc=Use question mark (?) in your query to represent dependency values when using AJAX
form.jdbcOptionsBinder.testConnection=Test Connection
form.jdbcOptionsBinder.connectionOk=Database connected
form.jdbcOptionsBinder.connectionFail=Not able to establish connection.

e. Register your plugin to the Felix Framework

We will have to register your plugin class in the Activator class (auto generated in the same class package) to tell the Felix Framework that this is a plugin.

public void start(BundleContext context) {
    registrationList = new ArrayList<ServiceRegistration>();
    //Register plugin here
    registrationList.add(context.registerService(JdbcOptionsBinder.class.getName(), new JdbcOptionsBinder(), null));
} 

f. Build it and test 

Then, let's upload the plugin jar to Manage Plugins. After uploading the jar file, double-check that the plugin is uploaded and activated correctly. 

Then, let's create an AJAX Cascading Drop-Down List in a form to test it. Let's create your test form as follows. 

Then, configure your select box and JDBC binder.

In the query, you will use the following query to get the user list based on group id.

select distinct username, firstName, groupId from dir_user u
join dir_user_group g on u.username=g.userId
where groupId in (?) group by username;

Configure the dependency to group. Then, test the result. 

The user select box options changed based on the selected values of the group select box.

Now, let's change the query to the following to test the Cascading Drop-Down List without using AJAX.

select distinct username, firstName, groupId from dir_user u
join dir_user_group g on u.username=g.userId
group by username;

Remember to un-tick the "Use AJAX for cascade options?" option to make it not use AJAX.

Yes, it works as well. Then, you can test the custom configuration and the test connection button. 

8. Take a step further, share it or sell it