/*
* Copyright 2002-2008 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.core;
import java.util.HashSet;
import java.util.Set;
import org.springframework.util.Assert;
/**
* Base class for decorating ClassLoaders such as {@link OverridingClassLoader}
* and {@link org.springframework.instrument.classloading.ShadowingClassLoader},
* providing common handling of excluded packages and classes.
*
* @author Juergen Hoeller
* @author Rod Johnson
* @since 2.5.2
*/
public abstract class DecoratingClassLoader extends ClassLoader {
private final Set<String> excludedPackages = new HashSet<String>();
private final Set<String> excludedClasses = new HashSet<String>();
private final Object exclusionMonitor = new Object();
/**
* Create a new DecoratingClassLoader with no parent ClassLoader.
*/
public DecoratingClassLoader() {
}
/**
* Create a new DecoratingClassLoader using the given parent ClassLoader
* for delegation.
*/
public DecoratingClassLoader(ClassLoader parent) {
super(parent);
}
/**
* Add a package name to exclude from decoration (e.g. overriding).
* <p>Any class whose fully-qualified name starts with the name registered
* here will be handled by the parent ClassLoader in the usual fashion.
* @param packageName the package name to exclude
*/
public void excludePackage(String packageName) {
Assert.notNull(packageName, "Package name must not be null");
synchronized (this.exclusionMonitor) {
this.excludedPackages.add(packageName);
}
}
/**
* Add a class name to exclude from decoration (e.g. overriding).
* <p>Any class name registered here will be handled by the parent
* ClassLoader in the usual fashion.
* @param className the class name to exclude
*/
public void excludeClass(String className) {
Assert.notNull(className, "Class name must not be null");
synchronized (this.exclusionMonitor) {
this.excludedClasses.add(className);
}
}
/**
* Determine whether the specified class is excluded from decoration
* by this class loader.
* <p>The default implementation checks against excluded packages and classes.
* @param className the class name to check
* @return whether the specified class is eligible
* @see #excludePackage
* @see #excludeClass
*/
protected boolean isExcluded(String className) {
synchronized (this.exclusionMonitor) {
if (this.excludedClasses.contains(className)) {
return true;
}
for (String packageName : this.excludedPackages) {
if (className.startsWith(packageName)) {
return true;
}
}
}
return false;
}
}
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