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6902010: (cl) Delay initialization of ClassLoader.parallelLoaders

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Reviewed-by: forax, mchung, valeriep
This commit is contained in:
Alan Bateman 2009-12-07 12:29:14 +00:00
parent 76e3aaa436
commit 21d2a75a16
1 changed files with 48 additions and 27 deletions
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75
jdk/src/share/classes/java/lang/ClassLoader.java
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@ -175,15 +175,8 @@ import sun.security.util.SecurityConstants;
public abstract class ClassLoader {
private static native void registerNatives();
// Set of classes which are registered as parallel capable class loaders
private static final Set<Class<? extends ClassLoader>> parallelLoaders
= Collections.newSetFromMap(Collections.synchronizedMap
(new WeakHashMap<Class<? extends ClassLoader>, Boolean>()));
static {
registerNatives();
parallelLoaders.add(ClassLoader.class);
}
// The parent class loader for delegation
@ -191,6 +184,52 @@ public abstract class ClassLoader {
// must be added *after* it.
private final ClassLoader parent;
/**
* Encapsulates the set of parallel capable loader types.
*/
private static class ParallelLoaders {
private ParallelLoaders() {}
// the set of parallel capable loader types
private static final Set<Class<? extends ClassLoader>> loaderTypes =
Collections.newSetFromMap(
new WeakHashMap<Class<? extends ClassLoader>, Boolean>());
static {
synchronized (loaderTypes) { loaderTypes.add(ClassLoader.class); }
}
/**
* Registers the given class loader type as parallel capabale.
* Returns {@code true} is successfully registered; {@code false} if
* loader's super class is not registered.
*/
static boolean register(Class<? extends ClassLoader> c) {
synchronized (loaderTypes) {
if (loaderTypes.contains(c.getSuperclass())) {
// register the class loader as parallel capable
// if and only if all of its super classes are.
// Note: given current classloading sequence, if
// the immediate super class is parallel capable,
// all the super classes higher up must be too.
loaderTypes.add(c);
return true;
} else {
return false;
}
}
}
/**
* Returns {@code true} if the given class loader type is
* registered as parallel capable.
*/
static boolean isRegistered(Class<? extends ClassLoader> c) {
synchronized (loaderTypes) {
return loaderTypes.contains(c);
}
}
}
// Maps class name to the corresponding lock object when the current
// class loader is parallel capable.
// Note: VM also uses this field to decide if the current class loader
@ -237,7 +276,7 @@ public abstract class ClassLoader {
private ClassLoader(Void unused, ClassLoader parent) {
this.parent = parent;
if (parallelLoaders.contains(this.getClass())) {
if (ParallelLoaders.isRegistered(this.getClass())) {
parallelLockMap = new ConcurrentHashMap<String, Object>();
package2certs = new ConcurrentHashMap<String, Certificate[]>();
domains =
@ -1194,24 +1233,7 @@ public abstract class ClassLoader {
* @since 1.7
*/
protected static boolean registerAsParallelCapable() {
Class<? extends ClassLoader> caller = getCaller(1);
Class superCls = caller.getSuperclass();
boolean result = false;
// Explicit synchronization needed for composite action
synchronized (parallelLoaders) {
if (!parallelLoaders.contains(caller)) {
if (parallelLoaders.contains(superCls)) {
// register the immediate caller as parallel capable
// if and only if all of its super classes are.
// Note: given current classloading sequence, if
// the immediate super class is parallel capable,
// all the super classes higher up must be too.
result = true;
parallelLoaders.add(caller);
}
} else result = true;
}
return result;
return ParallelLoaders.register(getCaller(1));
}
/**
@ -2174,4 +2196,3 @@ class SystemClassLoaderAction
return sys;
}
}