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Frameworks
Application frameworks present a challenge to tools like One-JAR because they are written with
certain assumed behaviors about classloading which may not always be valid when running under the
One-JAR ClassLoader. Because of extensive input from the One-JAR user community, release 0.97 now
has extensive (possibly full) support for the following frameworks:
- SpringFramework 3.0.2
- Google Guice 2.0
Because of the different assumptions about classloading (and in particular, what appears to
be a minor omission in the Guice URL resolvers), One-JAR must be configured differently depending
on which of the frameworks you wish to use.
The configuration is controlled by a META-INF/MANIFEST.MF setting at the One-JAR top level which
names the factory implementation class that implements IURLFactory:
One-Jar-URL-Factory: com.simontuffs.onejar.JarClassLoader$OneJarURLFactory
One-JAR supports custom generation of URL's based on a factory interface in the JarClassLoader:
// Injectable URL factory.
public static interface IURLFactory {
public URL getURL(String codebase, String resource) throws MalformedURLException;
public URL getCodeBase(String jar) throws MalformedURLException;
}
A factory must support getUrl(String codebase, String resource), returning a URL for a resource
at a given codebase. It must also support getCodeBase(String jar), returning a URL for a given codebase.
One-JAR comes pre-configured with two factories which return different kinds of URLs:
- com.simontuffs.onejar.JarClassLoader$OneJarURLFactory -- returns:
onejar:/<codebase>/<resource>
- com.simontuffs.onejar.JarClassLoader$FileURLFactory -- returns:
jar:file:<path-to-onejar>!/<codebase>/<resource
The FileURL URL's are injected with a java.net.URLStreamHandler which
knows how to tear-apart the "jar:" protocol. FileURL is the best choice for SpringFramework
applications, which use "jar:" protocol URL's in their annotation scanners.
The OneJarUrlFactory URL's rely on the global com.simontuffs.onejar.Handler which
One-JAR adds to the java.protocol.handler.pkgs system property on startup, so that
the URL resolving mechanisms know where to delegate the "onejar:" protocol URL requests.
You can inject your own implementation of IURLFactory into the One-JAR ClassLoader by setting
the One-Jar-URL-Factory property to your own implementation of IURLFactory
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