Override default exception hander

Support
#1

Dear Team,
Can i customize an exist exception handler of framework ?
Example NoUserSessionHandler ,i want to foward into login screen immediately after session expired.
Thanks!

#2

Hi,

There are two types of exception handlers in the platform and both can be overridden.

The first type is explained in the docs: Client-Level Exception Handlers - CUBA Platform. Developer’s Manual. To override such handler, use standard procedure of overriding beans as explained here: Extending Business Logic - CUBA Platform. Developer’s Manual, i.e. just register a new class with the same id in web-spring.xml.

NoUserSessionHandler belongs to the second type of handlers. To override it, specify an instance of ExceptionHandlersConfiguration bean in your web-spring.xml with a unique identifier and register your extended handler with it, for example:


<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd">

    <!-- Annotation-based beans -->
    <context:component-scan base-package="com.company.sample"/>

    <bean id="sample_exceptionHandlersConf" class="com.haulmont.cuba.web.exception.ExceptionHandlersConfiguration">
        <property name="handlerClasses">
            <list>
                <value>com.company.sample.web.SampleNoUserSessionHandler</value>
            </list>
        </property>
    </bean>

</beans>

Example of the overridden handler:


package com.company.sample.web;

import com.haulmont.cuba.web.App;
import com.haulmont.cuba.web.exception.NoUserSessionHandler;

import javax.annotation.Nullable;

public class SampleNoUserSessionHandler extends NoUserSessionHandler {

    @Override
    protected void doHandle(App app, String className, String message, @Nullable Throwable throwable) {
        app.getWindowManager().showNotification("Hello from SampleNoUserSessionHandler");
    }
}

All handlers of the second type specified in the project comes into play before provided by the platform, so your handler will effectively replace the default one.