Spring bean customization with configurable properties

Question

I have an xml bean configuration as follows:

<bean id="txManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory" />
        <property name="dataSource" ref="dataSource" />
        <property name="jpaDialect" ref="openJPADialect" />
    </bean>

I want to add a new property defaultTimeout, however I don't want to hard code it.

I want to instead put some class that will retrieve the value of this property from some in memory cache (doesn't matter from where actually)

I've heard and used before - org.springframework.beans.factory.config.PropertyPlaceholderConfigurer However it retrieves values from a property file, which is not exactly what I need.

Could you please advise my direction?

Answer 1

I want to put instead of this property some class that will retrieve value of this property from some in memory cache (doesn't matter from where actually)

How about injecting your txManager into this some class and set the defaultTimeout there?

Answer 2

Try looking into the com.typesafe.config library https://www.javadoc.io/doc/com.typesafe/config/1.2.1. This allows you to load configuration files.

Use this library to create a bean of type config. Something like this. This is a java configuration, but could be adapted to an XML implementation.

@Configuration
@EnableWebMvc
@ComponentScan(basePackages = "com.your.package")
public class WebMvcConfig extends WebMvcConfigurerAdapter {
    @Bean
    public Config properties() throws Exception {
        String path = ""; // path to properties file
        Config conf = ConfigFactory.parseFile(new File(path));

        return conf;
    }
}

Then in your component classes, you can autowire the bean and use the properties stored in the in memory bean.

@Autowired
private Config properties;
...
properties.getString("your property key");