org.apache.catalina.loader

Class StandardClassLoader

java.lang.Object

java.lang.ClassLoader

java.security.SecureClassLoader

java.net.URLClassLoader

org.apache.catalina.loader.StandardClassLoader

All Implemented Interfaces:

Closeable, AutoCloseable, Reloader

public class StandardClassLoader
extends URLClassLoader
implements Reloader

Subclass implementation of java.net.URLClassLoader that knows how to load classes from disk directories, as well as local and remote JAR files. It also implements the Reloader interface, to provide automatic reloading support to the associated loader.

In all cases, URLs must conform to the contract specified by URLClassLoader - any URL that ends with a "/" character is assumed to represent a directory; all other URLs are assumed to be the address of a JAR file.

IMPLEMENTATION NOTE - Local repositories are searched in the order they are added via the initial constructor and/or any subsequent calls to addRepository().

IMPLEMENTATION NOTE - At present, there are no dependencies from this class to any other Catalina class, so that it could be used independently.

Version:

$Revision: 1.3 $ $Date: 2006/03/12 01:27:02 $

Author:

Craig R. McClanahan, Remy Maucherat

Field Summary

Fields

Modifier and Type	Field and Description
protected int	debug The debugging detail level of this component.
protected boolean	delegate Should this class loader delegate to the parent class loader before searching its own repositories (i.e.
protected URLStreamHandlerFactory	factory URL stream handler for additional protocols.
protected ArrayList<String>	repositories The list of local repositories, in the order they should be searched for locally loaded classes or resources.

Constructor Summary

Constructors

Constructor and Description
StandardClassLoader() Construct a new ClassLoader with no defined repositories and no parent ClassLoader.
StandardClassLoader(ClassLoader parent) Construct a new ClassLoader with no defined repositories and the specified parent ClassLoader.
StandardClassLoader(ClassLoader parent, URLStreamHandlerFactory factory) Construct a new ClassLoader with no defined repositories and the specified parent ClassLoader.
StandardClassLoader(String[] repositories) Construct a new ClassLoader with the specified repositories and no parent ClassLoader.
StandardClassLoader(String[] repositories, ClassLoader parent) Construct a new ClassLoader with the specified repositories and parent ClassLoader.
StandardClassLoader(URL[] repositories) Construct a new ClassLoader with the specified repositories and no parent ClassLoader.
StandardClassLoader(URL[] repositories, ClassLoader parent) Construct a new ClassLoader with the specified repositories and parent ClassLoader.
StandardClassLoader(URLStreamHandlerFactory factory) Construct a new ClassLoader with no defined repositories and no parent ClassLoader, but with a stream handler factory.

Method Summary

Modifier and Type	Method and Description
void	addRepository(String repository) Add a new repository to the set of places this ClassLoader can look for classes to be loaded.
protected void	addRepositoryInternal(String repository) Add a repository to our internal array only.
protected static URL[]	convert(String[] input) Convert an array of String to an array of URL and return it.
protected static URL[]	convert(String[] input, URLStreamHandlerFactory factory) Convert an array of String to an array of URL and return it.
Class	findClass(String name) Find the specified class in our local repositories, if possible.
protected InputStream	findLoadedResource(String name) Finds the resource with the given name if it has previously been loaded and cached by this class loader, and return an input stream to the resource data.
URL	findResource(String name) Find the specified resource in our local repository, and return a URL refering to it, or null if this resource cannot be found.
Enumeration<URL>	findResources(String name) Return an enumeration of URLs representing all of the resources with the given name.
int	getDebug() Return the debugging detail level for this component.
boolean	getDelegate() Return the "delegate first" flag for this class loader.
protected PermissionCollection	getPermissions(CodeSource codeSource) Get the Permissions for a CodeSource.
URL	getResource(String name) Find the resource with the given name.
InputStream	getResourceAsStream(String name) Find the resource with the given name, and return an input stream that can be used for reading it.
Class	loadClass(String name) Load the class with the specified name.
Class	loadClass(String name, boolean resolve) Load the class with the specified name, searching using the following algorithm until it finds and returns the class.
boolean	modified() This class loader doesn't check for reloading.
protected static String	parseProtocol(String spec) Parse URL protocol.
void	setDebug(int debug) Set the debugging detail level for this component.
void	setDelegate(boolean delegate) Set the "delegate first" flag for this class loader.
protected void	setPermissions(String path) If there is a Java SecurityManager create a read FilePermission or JndiPermission for the file directory path.
protected void	setPermissions(URL url) If there is a Java SecurityManager add a read FilePermission or JndiPermission for URL.
String	toString() Render a String representation of this object.

Methods inherited from class java.net.URLClassLoader

addURL, close, definePackage, getURLs, newInstance, newInstance

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, getResources, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, registerAsParallelCapable, resolveClass, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSigners

Methods inherited from class java.lang.Object

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

Field Detail

debug

protected int debug

The debugging detail level of this component.

delegate

protected boolean delegate

Should this class loader delegate to the parent class loader before searching its own repositories (i.e. the usual Java2 delegation model)? If set to false, this class loader will search its own repositories first, and delegate to the parent only if the class or resource is not found locally.

repositories

protected ArrayList<String> repositories

The list of local repositories, in the order they should be searched for locally loaded classes or resources.

factory

protected URLStreamHandlerFactory factory

URL stream handler for additional protocols.

Constructor Detail

StandardClassLoader

public StandardClassLoader()

Construct a new ClassLoader with no defined repositories and no parent ClassLoader.

StandardClassLoader

public StandardClassLoader(URLStreamHandlerFactory factory)

Construct a new ClassLoader with no defined repositories and no parent ClassLoader, but with a stream handler factory.

Parameters:

factory - the URLStreamHandlerFactory to use when creating URLs

StandardClassLoader

public StandardClassLoader(ClassLoader parent)

Construct a new ClassLoader with no defined repositories and the specified parent ClassLoader.

Parameters:

parent - The parent ClassLoader

StandardClassLoader

public StandardClassLoader(ClassLoader parent,
                           URLStreamHandlerFactory factory)

Construct a new ClassLoader with no defined repositories and the specified parent ClassLoader.

Parameters:

parent - The parent ClassLoader

factory - the URLStreamHandlerFactory to use when creating URLs

StandardClassLoader

public StandardClassLoader(String[] repositories)

Construct a new ClassLoader with the specified repositories and no parent ClassLoader.

Parameters:

repositories - The initial set of repositories

StandardClassLoader

public StandardClassLoader(String[] repositories,
                           ClassLoader parent)

Construct a new ClassLoader with the specified repositories and parent ClassLoader.

Parameters:

repositories - The initial set of repositories

parent - The parent ClassLoader

StandardClassLoader

public StandardClassLoader(URL[] repositories)

Construct a new ClassLoader with the specified repositories and no parent ClassLoader.

Parameters:

repositories - The initial set of repositories

StandardClassLoader

public StandardClassLoader(URL[] repositories,
                           ClassLoader parent)

Construct a new ClassLoader with the specified repositories and parent ClassLoader.

Parameters:

repositories - The initial set of repositories

parent - The parent ClassLoader

Method Detail

getDebug

public int getDebug()

Return the debugging detail level for this component.

setDebug

public void setDebug(int debug)

Set the debugging detail level for this component.

Parameters:

debug - The new debugging detail level

getDelegate

public boolean getDelegate()

Return the "delegate first" flag for this class loader.

setDelegate

public void setDelegate(boolean delegate)

Set the "delegate first" flag for this class loader.

Parameters:

delegate - The new "delegate first" flag

setPermissions

protected void setPermissions(String path)

If there is a Java SecurityManager create a read FilePermission or JndiPermission for the file directory path.

Parameters:

path - file directory path

setPermissions

protected void setPermissions(URL url)

If there is a Java SecurityManager add a read FilePermission or JndiPermission for URL.

Parameters:

url - URL for a file or directory on local system

addRepository

public void addRepository(String repository)

Add a new repository to the set of places this ClassLoader can look for classes to be loaded.

Specified by:

addRepository in interface Reloader

Parameters:

repository - Name of a source of classes to be loaded, such as a directory pathname, a JAR file pathname, or a ZIP file pathname

Throws:

IllegalArgumentException - if the specified repository is invalid or does not exist

modified

public boolean modified()

This class loader doesn't check for reloading.

Specified by:

modified in interface Reloader

toString

public String toString()

Render a String representation of this object.

Overrides:

toString in class Object

findClass

public Class findClass(String name)
                throws ClassNotFoundException

Find the specified class in our local repositories, if possible. If not found, throw ClassNotFoundException.

Overrides:

findClass in class URLClassLoader

Parameters:

name - Name of the class to be loaded

Throws:

ClassNotFoundException - if the class was not found

findResource

public URL findResource(String name)

Find the specified resource in our local repository, and return a URL refering to it, or null if this resource cannot be found.

Overrides:

findResource in class URLClassLoader

Parameters:

name - Name of the resource to be found

findResources

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

Return an enumeration of URLs representing all of the resources with the given name. If no resources with this name are found, return an empty enumeration.

Overrides:

findResources in class URLClassLoader

Parameters:

name - Name of the resources to be found

Throws:

IOException - if an input/output error occurs

getResource

public URL getResource(String name)

Find the resource with the given name. A resource is some data (images, audio, text, etc.) that can be accessed by class code in a way that is independent of the location of the code. The name of a resource is a "/"-separated path name that identifies the resource. If the resource cannot be found, return null.

This method searches according to the following algorithm, returning as soon as it finds the appropriate URL. If the resource cannot be found, returns null.

• If the delegate property is set to true, call the getResource() method of the parent class loader, if any.
• Call findResource() to find this resource in our locally defined repositories.
• Call the getResource() method of the parent class loader, if any.

Overrides:

getResource in class ClassLoader

Parameters:

name - Name of the resource to return a URL for

getResourceAsStream

public InputStream getResourceAsStream(String name)

Find the resource with the given name, and return an input stream that can be used for reading it. The search order is as described for getResource(), after checking to see if the resource data has been previously cached. If the resource cannot be found, return null.

Overrides:

getResourceAsStream in class URLClassLoader

Parameters:

name - Name of the resource to return an input stream for

loadClass

public Class loadClass(String name)
                throws ClassNotFoundException

Load the class with the specified name. This method searches for classes in the same manner as loadClass(String, boolean) with false as the second argument.

Overrides:

loadClass in class ClassLoader

Parameters:

name - Name of the class to be loaded

Throws:

ClassNotFoundException - if the class was not found

loadClass

public Class loadClass(String name,
                       boolean resolve)
                throws ClassNotFoundException

Load the class with the specified name, searching using the following algorithm until it finds and returns the class. If the class cannot be found, returns ClassNotFoundException.

• Call findLoadedClass(String) to check if the class has already been loaded. If it has, the same Class object is returned.
• If the delegate property is set to true, call the loadClass() method of the parent class loader, if any.
• Call findClass() to find this class in our locally defined repositories.
• Call the loadClass() method of our parent class loader, if any.

If the class was found using the above steps, and the resolve flag is true, this method will then call resolveClass(Class) on the resulting Class object.

Overrides:

loadClass in class ClassLoader

Parameters:

name - Name of the class to be loaded

resolve - If true then resolve the class

Throws:

ClassNotFoundException - if the class was not found

getPermissions

protected final PermissionCollection getPermissions(CodeSource codeSource)

Get the Permissions for a CodeSource. If this instance of StandardClassLoader is for a web application context, add read FilePermissions for the base directory (if unpacked), the context URL, and jar file resources.

Overrides:

getPermissions in class URLClassLoader

Parameters:

codeSource - where the code was loaded from

Returns:

PermissionCollection for CodeSource

parseProtocol

protected static String parseProtocol(String spec)

Parse URL protocol.

Returns:

String protocol

addRepositoryInternal

protected void addRepositoryInternal(String repository)

Add a repository to our internal array only.

Parameters:

repository - The new repository

Throws:

IllegalArgumentException - if the manifest of a JAR file cannot be processed correctly

convert

protected static URL[] convert(String[] input)

Convert an array of String to an array of URL and return it.

Parameters:

input - The array of String to be converted

convert

protected static URL[] convert(String[] input,
                               URLStreamHandlerFactory factory)

Convert an array of String to an array of URL and return it.

Parameters:

input - The array of String to be converted

factory - Handler factory to use to generate the URLs

findLoadedResource

protected InputStream findLoadedResource(String name)

Finds the resource with the given name if it has previously been loaded and cached by this class loader, and return an input stream to the resource data. If this resource has not been cached, return null.

Parameters:

name - Name of the resource to return