javolution.lang.Initializer Class Reference

Collaboration diagram for javolution.lang.Initializer:

Public Member Functions
	Initializer (ClassLoader classLoader)
Class<?>[]	loadedClasses ()
void	loadClass (Class<?> cls)
boolean	initializeLoadedClasses ()

Static Public Attributes
static final Configurable< Boolean >	SHOW_INITIALIZED

Private Attributes
final ClassLoader	classLoader

Detailed Description

An initializer for all classes loaded by any given class loader.

Initialization of classes at startup (or during bundle activation) ensures a significantly improved worst case execution time especially if the classes has configuration logic to be executed then.

Javolution activator initialize Realtime classes when started. When running outside OSGi the method

javolution.osgi.internal.OSGiServices.initializeRealtimeClasses() 

can be used to that effect..

Class loading can be performed in a lazy manner and therefore some parts of the class loading process may be done on first use rather than at load time. Javolution bundle activator ensure that all its classes are initialized at start up. The following code illustrates how this can be done for any bundle. [code] public class MyActivator implements BundleActivator { public void start(BundleContext bc) throws Exception { Initializer initializer = new Initializer(MyActivator.class.getClassLoader()); initializer.loadClass(com.foo.internal.UnreferencedClass.class); // Load explicitly classes not directly or indirectly referenced. ... initializer.initializeLoadedClasses(); // Recursive loading/initialization. ... // Continue activation } }[/code]

This utility use reflection to find the classes loaded and may not be supported on all platforms.

Author

Jean-Marie Dautelle

Version

5.1, July 26, 2007

Definition at line 50 of file Initializer.java.

Constructor & Destructor Documentation

Initializer()

javolution.lang.Initializer.Initializer

(

ClassLoader

classLoader

)

Creates an initializer for the specified class loader.

Definition at line 69 of file Initializer.java.

                                                {
        this.classLoader = classLoader;
    }

References javolution.lang.Initializer.classLoader.

Member Function Documentation

initializeLoadedClasses()

boolean javolution.lang.Initializer.initializeLoadedClasses

(

)

Initializes all the loaded classes. If the initialization leads to more classes being loaded, these classes are initialized as well (recursive process).

Returns

true 

if initialization has been performed successfully;

false 

otherwise.

Definition at line 119 of file Initializer.java.

                                             {
        boolean isInitializationSuccessful = true;
        int nbrClassesInitialized = 0;
        while (true) {
            Class<?>[] classes = loadedClasses();
            if (classes == null) {
                LogContext
                        .debug("Automatic class initialization not supported.");
                return false;
            }
            if (nbrClassesInitialized >= classes.length)
                break; // Done.
            for (int i = nbrClassesInitialized; i < classes.length; i++) {
                Class<?> cls = classes[i];
                try {
                    if (SHOW_INITIALIZED.get())
                        LogContext.debug("Initialize ", cls.getName());
                    Class.forName(cls.getName(), true, classLoader);
                } catch (ClassNotFoundException ex) {
                    isInitializationSuccessful = false;
                    LogContext.error(ex); // Should never happen.
                }
            }
            nbrClassesInitialized = classes.length;
        }
        LogContext.debug("Initialization of ", nbrClassesInitialized,
                " classes loaded by ", classLoader);
        return isInitializationSuccessful;
    }

References javolution.lang.Initializer.classLoader, javolution.context.LogContext.debug(), javolution.context.LogContext.error(), javolution.lang.Configurable< T >.get(), javolution.lang.Initializer.loadedClasses(), and javolution.lang.Initializer.SHOW_INITIALIZED.

Referenced by javolution.osgi.internal.OSGiServices.initializeRealtimeClasses().

Here is the call graph for this function:

Here is the caller graph for this function:

loadClass()

void javolution.lang.Initializer.loadClass

(

Class<?>

cls

)

Loads the specified class (does not perform any initialization). This method is typically used to load unreferenced classes.

Definition at line 103 of file Initializer.java.

                                        {
        try {
            classLoader.loadClass(cls.getName());
        } catch (ClassNotFoundException e) {
            LogContext.debug("Class " + cls + " not found.");
        }
    }

References javolution.lang.Initializer.classLoader, and javolution.context.LogContext.debug().

Referenced by javolution.osgi.internal.OSGiServices.initializeRealtimeClasses().

Here is the call graph for this function:

Here is the caller graph for this function:

loadedClasses()

Class<?> [] javolution.lang.Initializer.loadedClasses

(

)

Returns the classes loaded by the class loader of this initializer or null if not supported by the platform.

Definition at line 78 of file Initializer.java.

                                      {
        Class<?> cls = classLoader.getClass();
        while (cls != java.lang.ClassLoader.class) {
            cls = cls.getSuperclass();
        }
        try {
            java.lang.reflect.Field fldClasses = cls
                    .getDeclaredField("classes");
            fldClasses.setAccessible(true);
            Vector<Class<?>> list = (Vector<Class<?>>) fldClasses
                    .get(classLoader);
            Class<?>[] classes = new Class<?>[list.size()];
            for (int i = 0; i < classes.length; i++) {
                classes[i] = list.get(i);
            }
            return classes;
        } catch (Throwable e) {
            return null;
        }
    }

References javolution.lang.Initializer.classLoader.

Referenced by javolution.lang.Initializer.initializeLoadedClasses().

Here is the caller graph for this function:

Member Data Documentation

classLoader

final ClassLoader javolution.lang.Initializer.classLoader

private

The class loader for this initializer

Definition at line 64 of file Initializer.java.

Referenced by javolution.lang.Initializer.initializeLoadedClasses(), javolution.lang.Initializer.Initializer(), javolution.lang.Initializer.loadClass(), and javolution.lang.Initializer.loadedClasses().

SHOW_INITIALIZED

final Configurable<Boolean> javolution.lang.Initializer.SHOW_INITIALIZED

static

Initial value:

= new Configurable<Boolean>() {
        @Override
        protected Boolean getDefault() {
            return false;
        }
    }

Indicates if the class being initialized should be logged (default

false 

).

Definition at line 56 of file Initializer.java.

Referenced by javolution.lang.Initializer.initializeLoadedClasses().

---

The documentation for this class was generated from the following file:

• Initializer.java