Customize attribute validation

package classextension;

import java.io.IOException;
import java.util.regex.*;
import com.esri.arcgis.geodatabase.*;
import com.esri.arcgis.interop.AutomationException;
import com.esri.arcgis.interop.extn.*;
import com.esri.arcgis.system.IPropertySet;
@ArcGISExtension(categories = {
    ArcGISCategories.GeoObjectClassExtensions
}

)public class EmailValidationExtension implements IClassExtension,
    IObjectClassExtension, IFeatureClassExtension, IObjectClassValidation{
    /**
     * The name of the e-mail address field to be validated.
     */
    private static final String EMAIL_FIELD_NAME = "email";
    /**
     * A regular expression pattern representing an e-mail address.
     */
    private static final String EMAIL_REGEX = "[\\w-]+@([\\w-]+\\.)+[\\w-]+";
    /**
     * The index of the e-mail address field in the extension's class. A value of –1
     * indicates that it could not be found during initialization.
     */
    int emailFieldIndex =  - 1;
    /**
     * The regex pattern used to evaluate e-mail field values.
     */
    private Pattern regexPattern = null;
    /************************************************************************************************
     * IClassExtension members
     ************************************************************************************************/
    /**
     * Initializes the extension, passing in a reference to its class helper and its extension properties.
     */
    public void init(IClassHelper classHelper, IPropertySet extensionProperties)
        throws IOException, AutomationException{
        // Get the index of the e-mail field.
        IClass baseClass = classHelper.esri_getClass();
        emailFieldIndex = baseClass.findField(EMAIL_FIELD_NAME);
        // Compile a regex pattern for e-mail validation.
        regexPattern = Pattern.compile(EMAIL_REGEX);
    }
    /**
     * Called when the extension's class is being disposed of from memory.
     */
    public void shutdown()throws IOException, AutomationException{
        // Do nothing.
    }
    /************************************************************************************************
     * IObjectClassValidation members
     ************************************************************************************************/
    /**
     * Validates the row.
     */
    public String validateRow(IRow row)throws IOException, AutomationException{
        return validateField(row, EMAIL_FIELD_NAME);
    }
    /**
     * Validates the row's specified attribute. 
     */
    public String validateField(IRow row, String fieldName)throws IOException,
        AutomationException{
        // Make sure the e-mail field is the field being validated and that its index was
        // successfully determined during validation.
        if (fieldName.equalsIgnoreCase(EMAIL_FIELD_NAME) && emailFieldIndex !=  - 1){
            try{
                // Check that the field value is not null before matching. 
                Object emailObj = row.getValue(emailFieldIndex);
                if (emailObj != null){
                    // Try to match the value with the regular expression matcher.
                    String emailAddress = (String)emailObj;
                    Matcher matcher = regexPattern.matcher(emailAddress);
                    if (matcher.matches()){
                        // The value is a match, return null to indicate it is valid.
                        return null;
                    }
                    else{
                        // The value is not a match.
                        return emailAddress.concat(" is not a valid email address.");
                    }
                }
            }
            catch (Exception exc){
                return "An error occurred during validation: " + exc.getMessage();
            }
        }
        return null;
    }
}

//Import the created class extension class files.
//Do not forget to add the class extension JAR file to the class path.
import classextensions.*;

//Declare the class variable.
private static final String EMAIL_FIELD_NAME = "email";

public void applyClassExtension(FeatureClass fc){
    try{
        //Verify the FieldName attribute is available in the feature class.
        //Verify that no other class extension is applied to the feature class.
        if ((fc.findField(EMAIL_FIELD_NAME) >  - 1) && (fc.getEXTCLSID() == null)){
            fc.changeSchemaLock(esriSchemaLock.esriExclusiveSchemaLock);
            // Create a unique identifier object (UID) and assign the extension.
            UID extUID = new UID();
            //Notice, the fully qualified class name of the created class extension Java class  
            //is passed as a parameter.
            extUID.setValue(classextension.EmailValidationExtension.class.getName());

            //Apply the class extension to the feature class.
            fc.alterClassExtensionCLSID(extUID, null);
            fc.changeSchemaLock(esriSchemaLock.esriSharedSchemaLock);
        }
    }
    catch (IOException e){

        e.printStackTrace();
    }

//Validates the input feature.
private void validateFeature(IFeature inFeature){
    IValidate validate = (IValidate)inFeature;
    String[] errorMessage = new String[1];
    boolean valid = false;
    try{
        valid = validate.validate(errorMessage);
    }
    catch (IOException e){
        e.printStackTrace();
    }
    if (!valid){
        System.out.println("Not Valid :" + errorMessage[0]);
    }
}