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com.aspectran.core.context.resource.SiblingsClassLoader Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2023 The Aspectran Project
*
* 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 com.aspectran.core.context.resource;
import com.aspectran.core.util.ToStringBuilder;
import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Objects;
import java.util.Set;
import static com.aspectran.core.util.ClassUtils.PACKAGE_SEPARATOR_CHAR;
/**
* Specialized class loader for Aspectran.
*/
public class SiblingsClassLoader extends ClassLoader {
private final int id;
private final SiblingsClassLoader root;
private final boolean firstborn;
private final String resourceLocation;
private final ResourceManager resourceManager;
private final List children = new LinkedList<>();
private Set excludeClassNames;
private Set excludePackageNames;
private int reloadedCount;
public SiblingsClassLoader() throws InvalidResourceException {
this(SiblingsClassLoader.class.getClassLoader());
}
public SiblingsClassLoader(ClassLoader parent) throws InvalidResourceException {
super(parent);
this.id = 1000;
this.root = this;
this.firstborn = true;
this.resourceLocation = null;
this.resourceManager = new LocalResourceManager(this);
}
public SiblingsClassLoader(String resourceLocation) throws InvalidResourceException {
this(resourceLocation, SiblingsClassLoader.class.getClassLoader());
}
public SiblingsClassLoader(String resourceLocation, ClassLoader parent) throws InvalidResourceException {
super(parent);
this.id = 1000;
this.root = this;
this.firstborn = true;
this.resourceLocation = resourceLocation;
this.resourceManager = new LocalResourceManager(this, resourceLocation);
}
public SiblingsClassLoader(String[] resourceLocations) throws InvalidResourceException {
this(resourceLocations, SiblingsClassLoader.class.getClassLoader());
}
public SiblingsClassLoader(String[] resourceLocations, ClassLoader parent) throws InvalidResourceException {
this(parent);
SiblingsClassLoader scl = this;
if (resourceLocations != null) {
for (String resourceLocation : resourceLocations) {
if (resourceLocation != null && !resourceLocation.isEmpty()) {
scl = scl.createChild(resourceLocation);
}
}
}
}
protected SiblingsClassLoader(String resourceLocation, SiblingsClassLoader parent) throws InvalidResourceException {
super(parent);
if (parent == null) {
throw new IllegalArgumentException("parent must not be null");
}
int numOfChildren = parent.addChild(this);
this.id = (Math.abs(parent.getId() / 1000) + 1) * 1000 + numOfChildren;
this.root = parent.getRoot();
this.firstborn = (numOfChildren == 1);
this.resourceLocation = resourceLocation;
this.resourceManager = new LocalResourceManager(this, resourceLocation);
}
private SiblingsClassLoader(ClassLoader parent, SiblingsClassLoader youngest) throws InvalidResourceException {
super(parent);
if (youngest == null) {
throw new IllegalArgumentException("youngest must not be null");
}
int numOfChildren = youngest.addChild(this);
this.id = (Math.abs(youngest.getId() / 1000) + 1) * 1000 + numOfChildren;
this.root = youngest;
this.firstborn = (numOfChildren == 1);
this.resourceLocation = null;
this.resourceManager = new LocalResourceManager(this);
}
public void setResourceLocations(String... resourceLocations) throws InvalidResourceException {
synchronized (children) {
if (!children.isEmpty()) {
children.clear();
}
SiblingsClassLoader scl = this;
if (resourceLocations != null) {
for (String resourceLocation : resourceLocations) {
if (resourceLocation != null && !resourceLocation.isEmpty()) {
scl = scl.createChild(resourceLocation);
}
}
}
}
}
public SiblingsClassLoader addGeneration(ClassLoader classLoader) throws InvalidResourceException {
SiblingsClassLoader youngest = root;
while (youngest.hasChildren()) {
youngest = youngest.getChildren().get(0);
}
return new SiblingsClassLoader(classLoader, youngest);
}
protected SiblingsClassLoader joinSibling(String resourceLocation) throws InvalidResourceException {
SiblingsClassLoader parent = (SiblingsClassLoader)getParent();
return parent.createChild(resourceLocation);
}
private SiblingsClassLoader createChild(String resourceLocation) throws InvalidResourceException {
if (!firstborn) {
throw new IllegalStateException("Only the first among siblings can create a child");
}
return new SiblingsClassLoader(resourceLocation, this);
}
/**
* Adds packages that this ClassLoader should not handle.
* Any class whose fully-qualified name starts with the name registered here will be handled
* by the parent ClassLoader in the usual fashion.
* @param packageNames package names that we be compared against fully qualified package names to exclude
*/
public void excludePackage(String... packageNames) {
if (packageNames == null) {
excludePackageNames = null;
} else {
for (String packageName : packageNames) {
if (excludePackageNames == null) {
excludePackageNames = new HashSet<>();
}
excludePackageNames.add(packageName + PACKAGE_SEPARATOR_CHAR);
}
}
}
/**
* Adds classes that this ClassLoader should not handle.
* Any class whose fully-qualified name starts with the name registered here will be handled
* by the parent ClassLoader in the usual fashion.
* @param classNames class names that we be compared against fully qualified class names to exclude
*/
public void excludeClass(String... classNames) {
if (classNames == null) {
excludeClassNames = null;
} else {
for (String className : classNames) {
if (!isExcludedPackage(className)) {
if (excludeClassNames == null) {
excludeClassNames = new HashSet<>();
}
excludeClassNames.add(className);
}
}
}
}
private boolean isExcluded(String className) {
return (isExcludedPackage(className) || isExcludedClass(className));
}
private boolean isExcludedPackage(String className) {
if (excludePackageNames != null) {
for (String packageName : excludePackageNames) {
if (className.startsWith(packageName)) {
return true;
}
}
}
return false;
}
private boolean isExcludedClass(String className) {
return (excludeClassNames != null && excludeClassNames.contains(className));
}
public int getId() {
return id;
}
public SiblingsClassLoader getRoot() {
return root;
}
public boolean isRoot() {
return (this == root);
}
public List getChildren() {
return children;
}
private int addChild(SiblingsClassLoader child) {
synchronized (children) {
children.add(child);
return children.size();
}
}
public boolean hasChildren() {
return !children.isEmpty();
}
public boolean isFirstborn() {
return firstborn;
}
public ResourceManager getResourceManager() {
return resourceManager;
}
public String getResourceLocation() {
return resourceLocation;
}
public synchronized void reload() throws InvalidResourceException {
reload(root);
}
private void reload(SiblingsClassLoader self) throws InvalidResourceException {
self.increaseReloadedCount();
if (self.getResourceManager() != null) {
self.getResourceManager().reset();
}
SiblingsClassLoader firstborn = null;
List siblings = new ArrayList<>();
for (SiblingsClassLoader child : self.getChildren()) {
if (child.isFirstborn()) {
firstborn = child;
} else {
siblings.add(child);
}
}
if (!siblings.isEmpty()) {
self.leave(siblings);
}
if (firstborn != null) {
reload(firstborn);
}
}
private void increaseReloadedCount() {
reloadedCount++;
}
private void leave(List siblings) {
for (SiblingsClassLoader sibling : siblings) {
ResourceManager rm = sibling.getResourceManager();
if (rm != null) {
rm.release();
}
children.remove(sibling);
}
}
@Override
protected Class loadClass(String name, boolean resolve) throws ClassNotFoundException {
synchronized (getClassLoadingLock(name)) {
// First, check if the class has already been loaded
Class c = findLoadedClass(name);
if (c == null) {
try {
ClassLoader parent = root.getParent();
if (parent != null) {
c = Class.forName(name, false, parent);
} else {
// Try loading the class with the system class loader
c = findSystemClass(name);
}
} catch (ClassNotFoundException e) {
// ClassNotFoundException thrown if class not found
// from the non-null parent class loader
}
if (c == null) {
// Search from local repositories
c = findClass(name);
}
}
if (resolve) {
resolveClass(c);
}
return c;
}
}
@Override
public Class findClass(String name) throws ClassNotFoundException {
Objects.requireNonNull(name);
try {
byte[] classData = loadClassData(name);
if (classData != null) {
return defineClass(name, classData, 0, classData.length);
} else {
throw new ClassNotFoundException(name);
}
} catch (InvalidResourceException e) {
throw new ClassNotFoundException(name, e);
}
}
private byte[] loadClassData(String className) throws InvalidResourceException {
if (isExcluded(className)) {
return null;
}
String resourceName = ResourceManager.classNameToResourceName(className);
Enumeration res = ResourceManager.getResources(getAllMembers(), resourceName);
URL url = null;
if (res.hasMoreElements()) {
url = res.nextElement();
}
if (url == null) {
return null;
}
try {
URLConnection connection = url.openConnection();
BufferedInputStream input = new BufferedInputStream(connection.getInputStream());
ByteArrayOutputStream output = new ByteArrayOutputStream();
int i;
while ((i = input.read()) != -1) {
output.write(i);
}
input.close();
byte[] classData = output.toByteArray();
output.close();
return classData;
} catch (IOException e) {
throw new InvalidResourceException("Unable to read class file: " + url, e);
}
}
@Override
public URL getResource(String name) {
ClassLoader parent = root.getParent();
URL url;
if (parent != null) {
url = parent.getResource(name);
} else {
url = getSystemClassLoader().getResource(name);
}
if (url == null) {
// Search from local repositories
url = findResource(name);
}
return url;
}
@Override
public Enumeration getResources(String name) throws IOException {
Objects.requireNonNull(name);
Enumeration parentResources = null;
ClassLoader parent = root.getParent();
if (parent != null) {
parentResources = parent.getResources(name);
}
return ResourceManager.getResources(getAllMembers(), name, parentResources);
}
@Override
public URL findResource(String name) {
Objects.requireNonNull(name);
URL url = null;
Enumeration res = ResourceManager.getResources(getAllMembers(), name);
if (res.hasMoreElements()) {
url = res.nextElement();
}
return url;
}
@Override
public Enumeration findResources(String name) {
Objects.requireNonNull(name);
Set urls = new LinkedHashSet<>();
Enumeration res = ResourceManager.getResources(getAllMembers(), name);
if (res.hasMoreElements()) {
urls.add(res.nextElement());
}
return Collections.enumeration(urls);
}
public Iterator getAllMembers() {
return getMembers(root);
}
public Enumeration getAllResources() {
return ResourceManager.getResources(getAllMembers());
}
@Override
public String toString() {
String name = getClass().getSimpleName() + '@' + Integer.toString(hashCode(), 16);
ToStringBuilder tsb = new ToStringBuilder(name);
tsb.append("id", id);
if (getParent() instanceof SiblingsClassLoader) {
tsb.append("parent", ((SiblingsClassLoader)getParent()).getId());
} else {
tsb.append("parent", getParent().getClass().getName());
}
tsb.append("root", this == root);
tsb.append("firstborn", firstborn);
tsb.append("resourceLocation", resourceLocation);
tsb.append("numberOfResources", resourceManager != null ? resourceManager.getNumberOfResources() : '?');
tsb.appendSize("numberOfChildren", children);
tsb.append("reloadedCount", reloadedCount);
return tsb.toString();
}
public static Iterator getMembers(final SiblingsClassLoader root) {
return new Iterator<>() {
private SiblingsClassLoader next = root;
private Iterator children = root.getChildren().iterator();
private SiblingsClassLoader firstChild;
@Override
public boolean hasNext() {
return (next != null);
}
@Override
public SiblingsClassLoader next() {
if (next == null) {
throw new NoSuchElementException();
}
SiblingsClassLoader current = next;
if (children.hasNext()) {
next = children.next();
if (firstChild == null) {
firstChild = next;
}
} else {
if (firstChild != null) {
children = firstChild.getChildren().iterator();
if (children.hasNext()) {
next = children.next();
firstChild = next;
} else {
next = null;
}
} else {
next = null;
}
}
return current;
}
@Override
public void remove() {
throw new UnsupportedOperationException("remove");
}
};
}
}
