File	Doc	Category	Size	Date	Package
ClassLoaderRepositorySupport.java	API Doc	Java SE 5 API	9373	Fri Aug 26 14:54:58 BST 2005	com.sun.jmx.mbeanserver

ClassLoaderRepositorySupport

• java.lang.Object

Fields Summary
private static final LoaderEntry[]	EMPTY_LOADER_ARRAY
private LoaderEntry[]	loaders List of class loaders Only read-only actions should be performed on this object. We do O(n) operations on this array, e.g. when removing a ClassLoader. The assumption is that the number of elements is small, probably less than ten, and that the vast majority of operations are searches (loadClass) which are by definition linear.
private final Hashtable	search List of valid search
private final Hashtable	loadersWithNames List of named class loaders.
private static final String	dbgTag

Constructors Summary

Methods Summary
private synchronized boolean	add(javax.management.ObjectName name, java.lang.ClassLoader cl) Same behaviour as add(Object o) in {@link java.util.List}. Replace the loader list with a new one in which the new loader has been added. List l = new ArrayList(Arrays.asList(loaders)); l.add(new LoaderEntry(name, cl)); loaders = (LoaderEntry[]) l.toArray(EMPTY_LOADER_ARRAY); return true;
public final synchronized void	addClassLoader(javax.management.ObjectName name, java.lang.ClassLoader loader) loadersWithNames.put(name, loader); if (!(loader instanceof PrivateClassLoader)) add(name, loader);
public final void	addClassLoader(java.lang.ClassLoader loader) add(null, loader);
private static void	debug(java.lang.String clz, java.lang.String func, java.lang.String info) Trace.send(Trace.LEVEL_DEBUG, Trace.INFO_MBEANSERVER,clz,func,info);
private static void	debug(java.lang.String func, java.lang.String info) debug(dbgTag, func, info);
public final java.lang.ClassLoader	getClassLoader(javax.management.ObjectName name) return (ClassLoader)loadersWithNames.get(name);
private static boolean	isDebugOn() return Trace.isSelected(Trace.LEVEL_DEBUG, Trace.INFO_MBEANSERVER);
private static boolean	isTraceOn() return Trace.isSelected(Trace.LEVEL_TRACE, Trace.INFO_MBEANSERVER);
public final java.lang.Class	loadClass(java.lang.String className) // from javax.management.loading.DefaultLoaderRepository return loadClass(loaders, className, null, null);
private java.lang.Class	loadClass(com.sun.jmx.mbeanserver.ClassLoaderRepositorySupport$LoaderEntry[] list, java.lang.String className, java.lang.ClassLoader without, java.lang.ClassLoader stop) final int size = list.length; for(int i=0; i<size; i++) { try { final ClassLoader cl = list[i].loader; if (cl == null) // bootstrap class loader return Class.forName(className, false, null); if (cl == without) continue; if (cl == stop) break; if (isTraceOn()) { trace("loadClass", "trying loader = " + cl); } /* We used to have a special case for "instanceof MLet" here, where we invoked the method loadClass(className, null) to prevent infinite recursion. But the rule whereby the MLet only consults loaders that precede it in the CLR (via loadClassBefore) means that the recursion can't happen, and the test here caused some legitimate classloading to fail. For example, if you have dependencies C->D->E with loaders {E D C} in the CLR in that order, you would expect to be able to load C. The problem is that while resolving D, CLR delegation is disabled, so it can't find E. */ return Class.forName(className, false, cl); } catch (ClassNotFoundException e) { // OK: continue with next class } } throw new ClassNotFoundException(className);
public final java.lang.Class	loadClassBefore(java.lang.ClassLoader stop, java.lang.String className) if (isTraceOn()) trace("loadClassBefore", className + "\tbefore " + stop); if (stop == null) return loadClass(loaders, className, null, null); startValidSearch(stop, className); try { return loadClass(loaders, className, null, stop); } finally { stopValidSearch(stop, className); }
public final java.lang.Class	loadClassWithout(java.lang.ClassLoader without, java.lang.String className) if (isTraceOn()) { trace("loadClassWithout", className + "\twithout " + without); } // without is null => just behave as loadClass // if (without == null) return loadClass(loaders, className, null, null); // We must try to load the class without the given loader. // startValidSearch(without, className); try { return loadClass(loaders, className, without, null); } finally { stopValidSearch(without, className); }
private synchronized boolean	remove(javax.management.ObjectName name, java.lang.ClassLoader cl) Same behaviour as remove(Object o) in {@link java.util.List}. Replace the loader list with a new one in which the old loader has been removed. The ObjectName may be null, in which case the entry to be removed must also have a null ObjectName and the ClassLoader values must match. If the ObjectName is not null, then the first entry with a matching ObjectName is removed, regardless of whether ClassLoader values match. (In fact, the ClassLoader parameter will usually be null in this case.) final int size = loaders.length; for (int i = 0; i < size; i++) { LoaderEntry entry = loaders[i]; boolean match = (name == null) ? cl == entry.loader : name.equals(entry.name); if (match) { LoaderEntry[] newloaders = new LoaderEntry[size - 1]; System.arraycopy(loaders, 0, newloaders, 0, i); System.arraycopy(loaders, i + 1, newloaders, i, size - 1 - i); loaders = newloaders; return true; } } return false;
public final void	removeClassLoader(java.lang.ClassLoader loader) remove(null, loader);
public final synchronized void	removeClassLoader(javax.management.ObjectName name) ClassLoader loader = (ClassLoader) loadersWithNames.remove(name); if (!(loader instanceof PrivateClassLoader)) remove(name, loader);
private synchronized void	startValidSearch(java.lang.ClassLoader aloader, java.lang.String className) // Check if we have such a current search // Vector excluded= (Vector) search.get(className); if ((excluded!= null) && (excluded.contains(aloader))) { if (isTraceOn()) { trace("startValidSearch", "already requested loader=" + aloader + " class= " + className); } throw new ClassNotFoundException(className); } // Add an entry // if (excluded == null) { excluded= new Vector(1); search.put(className, excluded); } excluded.addElement(aloader); if (isTraceOn()) { trace("startValidSearch", "loader=" + aloader + " class= " + className); }
private synchronized void	stopValidSearch(java.lang.ClassLoader aloader, java.lang.String className) // Retrieve the search. // Vector excluded= (Vector) search.get(className); if (excluded!= null) { excluded.removeElement(aloader); if (isTraceOn()) { trace("stopValidSearch", "loader=" + aloader + " class= " + className); } }
private static void	trace(java.lang.String clz, java.lang.String func, java.lang.String info) Trace.send(Trace.LEVEL_TRACE, Trace.INFO_MBEANSERVER,clz,func,info);
private static void	trace(java.lang.String func, java.lang.String info) trace(dbgTag, func, info);