Custom Class Loader

This is the manual for older MicroStream versions (Version < 5.0).

The new documentation (Version >= 5.0) is located at:

https://docs.microstream.one/

In certain environments or setups it is necessary to provide specific ClassLoader instances. This can be done by customizing the connection foundation.

If a single ClassLoader is sufficient, just create a new provider by handing over the instance:

EmbeddedStorageManager storage = EmbeddedStorage.Foundation(Paths.get("mydb"))
    .onConnectionFoundation(cf -> 
        cf.setClassLoaderProvider(ClassLoaderProvider.New(myClassLoader))    
    )
    .start();

Or return a ClassLoader depending on the requested type:

EmbeddedStorageManager storage = EmbeddedStorage.Foundation(Paths.get("mydb"))
    .onConnectionFoundation(cf -> 
        cf.setClassLoaderProvider(typeName -> {
            if(typeName.startsWith("com.company.module1."))
            {
                return module1ClassLoader;
            }
            if(typeName.startsWith("com.company.module2."))
            {
                return module2ClassLoader;
            }
            return ClassLoader.getSystemClassLoader();
        })    
    )
    .start();

Class Loader in Application Server

Most application servers load the session's classes with the context class loader. Just use the one of the current thread:

EmbeddedStorageManager storage = EmbeddedStorage.Foundation(Paths.get("mydb"))
    .onConnectionFoundation(cf -> 
        cf.setClassLoaderProvider(ClassLoaderProvider.New(
            Thread.currentThread().getContextClassLoader()
        ))    
    )
    .start();