org.apache.river.api.net

Class RFC3986URLClassLoader

java.lang.Object

java.lang.ClassLoader

java.security.SecureClassLoader

java.net.URLClassLoader

org.apache.river.api.net.RFC3986URLClassLoader

All Implemented Interfaces:

Closeable, AutoCloseable

public class RFC3986URLClassLoader
extends URLClassLoader

This class loader is responsible for loading classes and resources from a list of URLs which can refer to either directories or JAR files. Classes loaded by this URLClassLoader are granted permission to access the URLs contained in the URL search list.

Unlike java.net.URLClassLoader, CodeSource.equals(java.lang.Object) and CodeSource.hashCode() is based on Certificate and RFC3986 Uri.equals(java.lang.Object) and Uri.hashCode(), not URL.equals(java.lang.Object). SecureClassLoader uses the overridden CodeSource equality as a key to cache ProtectionDomain's.

The following property -Dnet.jini.loader.codebaseAnnotation=URL may be set from the command line to revert to URL.equals(java.lang.Object) and URL.hashCode().

This allows implementors of Remote to do two things:

1. Utilise replication of codebase servers or mirrors.
2. Use different domain names to ensure separation of proxy classes that otherwise utilise identical jar files

The locking strategy of this ClassLoader is by default, the standard ClassLoader strategy. This ClassLoader is also thread safe, so can use a Parallel loading / synchronization strategy if the platform supports it.

Since:

3.0.0

Constructor Summary

Constructors

Constructor and Description
RFC3986URLClassLoader(URL[] urls) Constructs a new URLClassLoader instance.
RFC3986URLClassLoader(URL[] urls, ClassLoader parent) Constructs a new URLClassLoader instance.
RFC3986URLClassLoader(URL[] searchUrls, ClassLoader parent, URLStreamHandlerFactory factory) Constructs a new URLClassLoader instance.

Method Summary

Modifier and Type	Method and Description
protected void	addURL(URL url) Adds the specified URL to the search list.
void	close() Java 6 compatible implementation that overrides Java 7 URLClassLoader.close() URLClassLoader implements Closeable in Java 7 to allow resources such as open jar files to be released.
protected Package	definePackage(String packageName, Manifest manifest, URL url) Defines a new package using the information extracted from the specified manifest.
protected Class<?>	findClass(String clsName) Tries to locate and load the specified class using the known URLs.
URL	findResource(String name) Returns an URL referencing the specified resource or null if the resource could not be found.
Enumeration<URL>	findResources(String name) Returns all known URLs which point to the specified resource.
URL[]	getURLs() Returns the search list of this URLClassLoader.
static URLClassLoader	newInstance(URL[] urls) Returns a new URLClassLoader instance for the given URLs and the system ClassLoader as its parent.
static URLClassLoader	newInstance(URL[] urls, ClassLoader parentCl) Returns a new URLClassLoader instance for the given URLs and the specified ClassLoader as its parent.

Methods inherited from class java.net.URLClassLoader

getPermissions, getResourceAsStream

Methods inherited from class java.security.SecureClassLoader

defineClass, defineClass

Methods inherited from class java.lang.ClassLoader

clearAssertionStatus, defineClass, defineClass, defineClass, defineClass, definePackage, findLibrary, findLoadedClass, findSystemClass, getClassLoadingLock, getPackage, getPackages, getParent, getResource, getResources, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, loadClass, loadClass, registerAsParallelCapable, resolveClass, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSigners

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RFC3986URLClassLoader

public RFC3986URLClassLoader(URL[] urls)

Constructs a new URLClassLoader instance. The newly created instance will have the system ClassLoader as its parent. URLs that end with "/" are assumed to be directories, otherwise they are assumed to be JAR files.

Parameters:

urls - the list of URLs where a specific class or file could be found.

Throws:

SecurityException - if a security manager exists and its checkCreateClassLoader() method doesn't allow creation of new ClassLoaders.

RFC3986URLClassLoader

public RFC3986URLClassLoader(URL[] urls,
                             ClassLoader parent)

Constructs a new URLClassLoader instance. The newly created instance will have the system ClassLoader as its parent. URLs that end with "/" are assumed to be directories, otherwise they are assumed to be JAR files.

Parameters:

urls - the list of URLs where a specific class or file could be found.

parent - the class loader to assign as this loader's parent.

Throws:

SecurityException - if a security manager exists and its checkCreateClassLoader() method doesn't allow creation of new class loaders.

RFC3986URLClassLoader

public RFC3986URLClassLoader(URL[] searchUrls,
                             ClassLoader parent,
                             URLStreamHandlerFactory factory)

Constructs a new URLClassLoader instance. The newly created instance will have the specified ClassLoader as its parent and use the specified factory to create stream handlers. URLs that end with "/" are assumed to be directories, otherwise they are assumed to be JAR files.

Parameters:

searchUrls - the list of URLs where a specific class or file could be found.

parent - the ClassLoader to assign as this loader's parent.

factory - the factory that will be used to create protocol-specific stream handlers.

Throws:

SecurityException - if a security manager exists and its checkCreateClassLoader() method doesn't allow creation of new ClassLoaders.

Method Detail

addURL

protected void addURL(URL url)

Adds the specified URL to the search list.

Overrides:

addURL in class URLClassLoader

Parameters:

url - the URL which is to add.

findResources

public Enumeration<URL> findResources(String name)
                               throws IOException

Returns all known URLs which point to the specified resource.

Overrides:

findResources in class URLClassLoader

Parameters:

name - the name of the requested resource.

Returns:

the enumeration of URLs which point to the specified resource.

Throws:

IOException - if an I/O error occurs while attempting to connect.

getURLs

public URL[] getURLs()

Returns the search list of this URLClassLoader.

Overrides:

getURLs in class URLClassLoader

Returns:

the list of all known URLs of this instance.

newInstance

public static URLClassLoader newInstance(URL[] urls)

Returns a new URLClassLoader instance for the given URLs and the system ClassLoader as its parent. The method loadClass() of the new instance will call SecurityManager.checkPackageAccess() before loading a class.

Parameters:

urls - the list of URLs that is passed to the new URLClassloader.

Returns:

the created URLClassLoader instance.

newInstance

public static URLClassLoader newInstance(URL[] urls,
                                         ClassLoader parentCl)

Returns a new URLClassLoader instance for the given URLs and the specified ClassLoader as its parent. The method loadClass() of the new instance will call the SecurityManager's checkPackageAccess() before loading a class.

Parameters:

urls - the list of URLs that is passed to the new URLClassloader.

parentCl - the parent class loader that is passed to the new URLClassloader.

Returns:

the created URLClassLoader instance.

findClass

protected Class<?> findClass(String clsName)
                      throws ClassNotFoundException

Tries to locate and load the specified class using the known URLs. If the class could be found, a class object representing the loaded class will be returned. The locking and synchronization strategy of this method is the responsibility of the caller.

Overrides:

findClass in class URLClassLoader

Parameters:

clsName - the name of the class which has to be found.

Returns:

the class that has been loaded.

Throws:

ClassNotFoundException - if the specified class cannot be loaded.

findResource

public URL findResource(String name)

Returns an URL referencing the specified resource or null if the resource could not be found.

Overrides:

findResource in class URLClassLoader

Parameters:

name - the name of the requested resource.

Returns:

the URL which points to the given resource.

definePackage

protected Package definePackage(String packageName,
                                Manifest manifest,
                                URL url)
                         throws IllegalArgumentException

Defines a new package using the information extracted from the specified manifest.

Overrides:

definePackage in class URLClassLoader

Parameters:

packageName - the name of the new package.

manifest - the manifest containing additional information for the new package.

url - the URL to the code source for the new package.

Returns:

the created package.

Throws:

IllegalArgumentException - if a package with the given name already exists.

close

public void close()
           throws IOException

Java 6 compatible implementation that overrides Java 7 URLClassLoader.close() URLClassLoader implements Closeable in Java 7 to allow resources such as open jar files to be released. Closes any open resources and prevents this ClassLoader loading any additional classes or resources. TODO: Add support for nested Exceptions when support for Java 6 is dropped.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class URLClassLoader

Throws:

IOException - if closing any file opened by this ClassLoader causes an IOException, only the first instance is thrown.