Spring Environment Property Source Configuration

Question

I\'m working on an application library with a utility class called \"Config\" which is backed by the Spring Environment object and provides strongl

Answer 1

I came up with the following which seems to work, but I'm fairly new to Spring, so I'm not so sure how it will hold up under different use cases.

Basically, the approach is to extend PropertySourcesPlaceholderConfigurer and add a setter to allow the user to easily configure a List of PropertySource objects in XML. After creation, the property sources are copied to the current Environment.

This basically allows the property sources to be configured in one place, but used by both placholder configuration and Environment.getProperty scenarios.

Extended PropertySourcesPlaceholderConfigurer

public class ConfigSourcesConfigurer 
        extends PropertySourcesPlaceholderConfigurer
        implements EnvironmentAware, InitializingBean {

    private Environment environment;
    private List sourceList;

    // Allow setting property sources as a List for easier XML configuration
    public void setPropertySources(List propertySources) {

        this.sourceList = propertySources;
        MutablePropertySources sources = new MutablePropertySources();
        copyListToPropertySources(this.sourceList, sources);        
        super.setPropertySources(sources);
    }

    @Override
    public void setEnvironment(Environment environment) {
        // save off Environment for later use
        this.environment = environment;
        super.setEnvironment(environment);
    }

    @Override
    public void afterPropertiesSet() throws Exception {

        // Copy property sources to Environment
        MutablePropertySources envPropSources = ((ConfigurableEnvironment)environment).getPropertySources();
        copyListToPropertySources(this.sourceList, envPropSources);
    }

    private void copyListToPropertySources(List list, MutablePropertySources sources) {

        // iterate in reverse order to insure ordering in property sources object
        for(int i = list.size() - 1; i >= 0; i--) {
            sources.addFirst(list.get(i));
        }
    }
}

beans.xml file showing basic configuration