Set a ${property} at runtime in the application context

[ge0ffrey]

In my application context I want to be able to do
<property name="serviceUrl" value="${webappContextUrl}/myservice.service">

But ${webappContextUrl} is determined at runtime initialization and it's not in a *.properties file.
Instead a bean called JnlpWebappContextUrlLocator determines it.
How do I make my JnlpWebappContextUrlLocator.getWebAppContextUrl() bind to ${webappContextUrl} in the application context?

/**
 * @author Geoffrey De Smet
 */
public class JnlpWebappContextUrlLocator {

    private String fallBackWebAppContextUrl;

    public String getFallBackWebAppContextUrl() {
        return fallBackWebAppContextUrl;
    }

    public void setFallBackWebAppContextUrl(String fallBackWebAppContextUrl) {
        this.fallBackWebAppContextUrl = fallBackWebAppContextUrl;
    }

    /**
     * Uses the webstart API to determine the webapp context.
     * If used outside of webstart, <code>fallBackWebAppContextUrl</code> is returned.
     * @return the url to the webapp ending with a slash
     */
    public String getWebAppContextUrl&#40;&#41; &#123;
        String webAppContextUrl;
        try &#123;
            BasicService basicService = &#40;BasicService&#41; ServiceManager.lookup&#40;"javax.jnlp.BasicService"&#41;;
            String codeBase = basicService.getCodeBase&#40;&#41;.toExternalForm&#40;&#41;;
            // Remove "jnlp/" or "jnlp"
            int webAppContextUrlLength = codeBase.lastIndexOf&#40;"jnlp"&#41;; // TODO better solution required
            webAppContextUrl = codeBase.substring&#40;0, webAppContextUrlLength&#41;;
        &#125; catch &#40;UnavailableServiceException e&#41; &#123;
            // TODO logging
            webAppContextUrl = fallBackWebAppContextUrl;
        &#125;
        return webAppContextUrl;
    &#125;
&#125;

PS: I 'll submit it as a patch to spring rich

[Costin Leau]

I don't think there is an easy way - the post configurator for properties is active at configuration time while your property is evaluated at runtime (after the context has been evaluated and instantiated). I think you should use a different mechanism.

[ge0ffrey]

How is the lifecycle need of my class different from that of org.springframework.beans.factory.config.PropertyP laceholderConfigurer?

[Costin Leau]

You need to call a mehtod on a bean if I understood correctly. This means that your bean has to be already intialized. With property files you have the info available at runtime but before the context is parsed.

[ge0ffrey]

It's possible, look at ServletContextPropertyPlaceholderConfigurer

[Costin Leau]

Right! I had no idea there is a property place holder for web application also .