URLs this class
* loader will retrieve classes and resources by fetching them from
* possible remote locations. Each URL is searched in
* order in which it was added. If the file portion of the
* URL ends with a '/' character then it is interpreted
* as a base directory, otherwise it is interpreted as a jar file from
* which the classes/resources are resolved.
*
* New instances can be created by two static
* newInstance() methods or by three public
* contructors. Both ways give the option to supply an initial array
* of URLs and (optionally) a parent classloader (that is
* different from the standard system class loader).
Normally creating a URLClassLoader throws a
* SecurityException if a SecurityManager is
* installed and the checkCreateClassLoader() method does
* not return true. But the newInstance() methods may be
* used by any code as long as it has permission to acces the given
* URLs. URLClassLoaders created by the
* newInstance() methods also explicitly call the
* checkPackageAccess() method of
* SecurityManager if one is installed before trying to
* load a class. Note that only subclasses of
* URLClassLoader can add new URLs after the
* URLClassLoader had been created. But it is always possible to get
* an array of all URLs that the class loader uses to resolve classes
* and resources by way of the getURLs() method.
Open issues: *
definePackage() and sealing work
* precisely?newInstance() but do we have to use it in more
* places?URLStreamHandlers has not been tested.newInstance()
* or null when created through a normal constructor or when no
* SecurityManager was installed.
*/
private final AccessControlContext securityContext;
// Helper classes
/**
* A URLLoader contains all logic to load resources from a
* given base URL.
*/
abstract static class URLLoader
{
/**
* Our classloader to get info from if needed.
*/
final URLClassLoader classloader;
/**
* The base URL from which all resources are loaded.
*/
final URL baseURL;
/**
* A CodeSource without any associated certificates.
* It is common for classes to not have certificates associated
* with them. If they come from the same URLLoader
* then it is safe to share the associated CodeSource
* between them since CodeSource is immutable.
*/
final CodeSource noCertCodeSource;
URLLoader(URLClassLoader classloader, URL baseURL)
{
this(classloader, baseURL, baseURL);
}
URLLoader(URLClassLoader classloader, URL baseURL, URL overrideURL)
{
this.classloader = classloader;
this.baseURL = baseURL;
this.noCertCodeSource = new CodeSource(overrideURL, null);
}
/**
* Returns a Class loaded by this
* URLLoader, or null when this loader
* either can't load the class or doesn't know how to load classes
* at all.
*/
Class getClass(String className)
{
return null;
}
/**
* Returns a Resource loaded by this
* URLLoader, or null when no
* Resource with the given name exists.
*/
abstract Resource getResource(String s);
/**
* Returns the Manifest associated with the
* Resources loaded by this URLLoader or
* null there is no such Manifest.
*/
Manifest getManifest()
{
return null;
}
Vector getClassPath()
{
return null;
}
}
/**
* A Resource represents a resource in some
* URLLoader. It also contains all information (e.g.,
* URL, CodeSource, Manifest and
* InputStream) that is necessary for loading resources
* and creating classes from a URL.
*/
abstract static class Resource
{
final URLLoader loader;
Resource(URLLoader loader)
{
this.loader = loader;
}
/**
* Returns the non-null CodeSource associated with
* this resource.
*/
CodeSource getCodeSource()
{
Certificate[] certs = getCertificates();
if (certs == null)
return loader.noCertCodeSource;
else
return new CodeSource(loader.baseURL, certs);
}
/**
* Returns Certificates associated with this
* resource, or null when there are none.
*/
Certificate[] getCertificates()
{
return null;
}
/**
* Return a URL that can be used to access this resource.
*/
abstract URL getURL();
/**
* Returns the size of this Resource in bytes or
* -1 when unknown.
*/
abstract int getLength();
/**
* Returns the non-null InputStream through which
* this resource can be loaded.
*/
abstract InputStream getInputStream() throws IOException;
}
/**
* A JarURLLoader is a type of URLLoader
* only loading from jar url.
*/
static final class JarURLLoader extends URLLoader
{
final JarFile jarfile; // The jar file for this url
final URL baseJarURL; // Base jar: url for all resources loaded from jar
Vector classPath; // The "Class-Path" attribute of this Jar's manifest
public JarURLLoader(URLClassLoader classloader, URL baseURL,
URL absoluteUrl)
{
super(classloader, baseURL, absoluteUrl);
// Cache url prefix for all resources in this jar url.
String external = baseURL.toExternalForm();
StringBuffer sb = new StringBuffer(external.length() + 6);
sb.append("jar:");
sb.append(external);
sb.append("!/");
String jarURL = sb.toString();
this.classPath = null;
URL baseJarURL = null;
JarFile jarfile = null;
try
{
baseJarURL =
new URL(null, jarURL, classloader.getURLStreamHandler("jar"));
jarfile =
((JarURLConnection) baseJarURL.openConnection()).getJarFile();
Manifest manifest;
Attributes attributes;
String classPathString;
if ((manifest = jarfile.getManifest()) != null
&& (attributes = manifest.getMainAttributes()) != null
&& ((classPathString
= attributes.getValue(Attributes.Name.CLASS_PATH))
!= null))
{
this.classPath = new Vector();
StringTokenizer st = new StringTokenizer(classPathString, " ");
while (st.hasMoreElements ())
{
String e = st.nextToken ();
try
{
URL url = new URL(baseURL, e);
this.classPath.add(url);
}
catch (java.net.MalformedURLException xx)
{
// Give up
}
}
}
}
catch (IOException ioe)
{
/* ignored */
}
this.baseJarURL = baseJarURL;
this.jarfile = jarfile;
}
/** get resource with the name "name" in the jar url */
Resource getResource(String name)
{
if (jarfile == null)
return null;
if (name.startsWith("/"))
name = name.substring(1);
JarEntry je = jarfile.getJarEntry(name);
if (je != null)
return new JarURLResource(this, name, je);
else
return null;
}
Manifest getManifest()
{
try
{
return (jarfile == null) ? null : jarfile.getManifest();
}
catch (IOException ioe)
{
return null;
}
}
Vector getClassPath()
{
return classPath;
}
}
static final class JarURLResource extends Resource
{
private final JarEntry entry;
private final String name;
JarURLResource(JarURLLoader loader, String name, JarEntry entry)
{
super(loader);
this.entry = entry;
this.name = name;
}
InputStream getInputStream() throws IOException
{
return ((JarURLLoader) loader).jarfile.getInputStream(entry);
}
int getLength()
{
return (int) entry.getSize();
}
Certificate[] getCertificates()
{
// We have to get the entry from the jar file again, because the
// certificates will not be available until the entire entry has
// been read.
return ((JarEntry) ((JarURLLoader) loader).jarfile.getEntry(name))
.getCertificates();
}
URL getURL()
{
try
{
return new URL(((JarURLLoader) loader).baseJarURL, name,
loader.classloader.getURLStreamHandler("jar"));
}
catch (MalformedURLException e)
{
InternalError ie = new InternalError();
ie.initCause(e);
throw ie;
}
}
}
/**
* Loader for remote directories.
*/
static final class RemoteURLLoader extends URLLoader
{
private final String protocol;
RemoteURLLoader(URLClassLoader classloader, URL url)
{
super(classloader, url);
protocol = url.getProtocol();
}
/**
* Get a remote resource.
* Returns null if no such resource exists.
*/
Resource getResource(String name)
{
try
{
URL url =
new URL(baseURL, name, classloader.getURLStreamHandler(protocol));
URLConnection connection = url.openConnection();
// Open the connection and check the stream
// just to be sure it exists.
int length = connection.getContentLength();
InputStream stream = connection.getInputStream();
// We can do some extra checking if it is a http request
if (connection instanceof HttpURLConnection)
{
int response =
((HttpURLConnection) connection).getResponseCode();
if (response / 100 != 2)
return null;
}
if (stream != null)
return new RemoteResource(this, name, url, stream, length);
else
return null;
}
catch (IOException ioe)
{
return null;
}
}
}
/**
* A resource from some remote location.
*/
static final class RemoteResource extends Resource
{
private final URL url;
private final InputStream stream;
private final int length;
RemoteResource(RemoteURLLoader loader, String name, URL url,
InputStream stream, int length)
{
super(loader);
this.url = url;
this.stream = stream;
this.length = length;
}
InputStream getInputStream() throws IOException
{
return stream;
}
public int getLength()
{
return length;
}
public URL getURL()
{
return url;
}
}
/**
* A SoURLLoader is a type of URLLoader
* that loads classes and resources from a shared library.
*/
final static class SoURLLoader extends URLLoader
{
SharedLibHelper helper;
SoURLLoader(URLClassLoader classloader, URL url)
{
this(classloader, url, url);
}
SoURLLoader(URLClassLoader classloader, URL url, URL overrideURL)
{
super(classloader, url, overrideURL);
helper = SharedLibHelper.findHelper(classloader, url.getFile(),
noCertCodeSource, true);
}
Class getClass(String className)
{
return helper.findClass(className);
}
Resource getResource(String name)
{
URL url = helper.findResource(name);
if (url == null)
return null;
return new SoResource(this, url);
}
}
final static class SoResource extends Resource
{
SoResource(SoURLLoader loader, URL url)
{
super(loader);
this.url = url;
}
InputStream getInputStream() throws IOException
{
URLConnection conn = url.openConnection();
return conn.getInputStream();
}
public int getLength()
{
// FIXME we could find this by asking the core object.
return -1;
}
public URL getURL ()
{
return url;
}
final URL url;
}
/**
* A FileURLLoader is a type of URLLoader
* only loading from file url.
*/
static final class FileURLLoader extends URLLoader
{
File dir; //the file for this file url
FileURLLoader(URLClassLoader classloader, URL url, URL absoluteUrl)
{
super(classloader, url, absoluteUrl);
dir = new File(absoluteUrl.getFile());
}
/** get resource with the name "name" in the file url */
Resource getResource(String name)
{
try
{
File file = new File(dir, name).getCanonicalFile();
if (file.exists() && !file.isDirectory())
return new FileResource(this, file);
}
catch (IOException e)
{
// Fall through...
}
return null;
}
}
static final class FileResource extends Resource
{
final File file;
FileResource(FileURLLoader loader, File file)
{
super(loader);
this.file = file;
}
InputStream getInputStream() throws IOException
{
// Delegate to the URL content handler mechanism to retrieve an
// HTML representation of the directory listing if a directory
if (file.isDirectory())
{
URL url = getURL();
return url.openStream();
}
// Otherwise simply return a FileInputStream
return new FileInputStream(file);
}
public int getLength()
{
// Delegate to the URL content handler mechanism to retrieve the
// length of the HTML representation of the directory listing if
// a directory, or -1 if an exception occurs opening the directory.
if (file.isDirectory())
{
URL url = getURL();
try
{
URLConnection connection = url.openConnection();
return connection.getContentLength();
}
catch (IOException e)
{
return -1;
}
}
// Otherwise simply return the file length
return (int) file.length();
}
public URL getURL()
{
try
{
return file.toURL();
}
catch (MalformedURLException e)
{
InternalError ie = new InternalError();
ie.initCause(e);
throw ie;
}
}
}
/**
* A CoreURLLoader is a type of URLLoader
* only loading from core url.
*/
static final class CoreURLLoader extends URLLoader
{
private String dir;
CoreURLLoader(URLClassLoader classloader, URL url)
{
super(classloader, url);
dir = baseURL.getFile();
}
/** get resource with the name "name" in the core url */
Resource getResource(String name)
{
Core core = Core.find (dir + name);
if (core != null)
return new CoreResource(this, name, core);
return null;
}
}
static final class CoreResource extends Resource
{
private final Core core;
private final String name;
CoreResource(CoreURLLoader loader, String name, Core core)
{
super(loader);
this.core = core;
this.name = name;
}
InputStream getInputStream() throws IOException
{
return new CoreInputStream(core);
}
public int getLength()
{
return core.length;
}
public URL getURL()
{
try
{
return new URL(loader.baseURL, name,
loader.classloader.getURLStreamHandler("core"));
}
catch (MalformedURLException e)
{
InternalError ie = new InternalError();
ie.initCause(e);
throw ie;
}
}
}
// Constructors
/**
* Creates a URLClassLoader that gets classes from the supplied URLs.
* To determine if this classloader may be created the constructor of
* the super class (SecureClassLoader) is called first, which
* can throw a SecurityException. Then the supplied URLs are added
* in the order given to the URLClassLoader which uses these URLs to
* load classes and resources (after using the default parent ClassLoader).
*
* @param urls Locations that should be searched by this ClassLoader when
* resolving Classes or Resources.
* @exception SecurityException if the SecurityManager disallows the
* creation of a ClassLoader.
* @see SecureClassLoader
*/
public URLClassLoader(URL[] urls) throws SecurityException
{
super();
this.factory = null;
this.securityContext = null;
addURLs(urls);
}
/**
* Creates a URLClassLoader that gets classes from the supplied
* URLs.
* To determine if this classloader may be created the constructor of
* the super class (SecureClassLoader) is called first, which
* can throw a SecurityException. Then the supplied URLs are added
* in the order given to the URLClassLoader which uses these URLs to
* load classes and resources (after using the supplied parent ClassLoader).
* @param urls Locations that should be searched by this ClassLoader when
* resolving Classes or Resources.
* @param parent The parent class loader used before trying this class
* loader.
* @exception SecurityException if the SecurityManager disallows the
* creation of a ClassLoader.
* @exception SecurityException
* @see SecureClassLoader
*/
public URLClassLoader(URL[] urls, ClassLoader parent)
throws SecurityException
{
super(parent);
this.factory = null;
this.securityContext = null;
addURLs(urls);
}
// Package-private to avoid a trampoline constructor.
/**
* Package-private constructor used by the static
* newInstance(URL[]) method. Creates an
* URLClassLoader with the given parent but without any
* URLs yet. This is used to bypass the normal security
* check for creating classloaders, but remembers the security
* context which will be used when defining classes. The
* URLs to load from must be added by the
* newInstance() method in the security context of the
* caller.
*
* @param securityContext the security context of the unprivileged code.
*/
URLClassLoader(ClassLoader parent, AccessControlContext securityContext)
{
super(parent);
this.factory = null;
this.securityContext = securityContext;
}
/**
* Creates a URLClassLoader that gets classes from the supplied URLs.
* To determine if this classloader may be created the constructor of
* the super class (SecureClassLoader) is called first, which
* can throw a SecurityException. Then the supplied URLs are added
* in the order given to the URLClassLoader which uses these URLs to
* load classes and resources (after using the supplied parent ClassLoader).
* It will use the supplied URLStreamHandlerFactory to get the
* protocol handlers of the supplied URLs.
* @param urls Locations that should be searched by this ClassLoader when
* resolving Classes or Resources.
* @param parent The parent class loader used before trying this class
* loader.
* @param factory Used to get the protocol handler for the URLs.
* @exception SecurityException if the SecurityManager disallows the
* creation of a ClassLoader.
* @exception SecurityException
* @see SecureClassLoader
*/
public URLClassLoader(URL[] urls, ClassLoader parent,
URLStreamHandlerFactory factory)
throws SecurityException
{
super(parent);
this.securityContext = null;
this.factory = factory;
addURLs(urls);
// If this factory is still not in factoryCache, add it,
// since we only support three protocols so far, 5 is enough
// for cache initial size
synchronized (factoryCache)
{
if (factory != null && factoryCache.get(factory) == null)
factoryCache.put(factory, new HashMap(5));
}
}
// Methods
/**
* Adds a new location to the end of the internal URL store.
* @param newUrl the location to add
*/
protected void addURL(URL newUrl)
{
urls.add(newUrl);
addURLImpl(newUrl);
}
private void addURLImpl(URL newUrl)
{
synchronized (this)
{
if (newUrl == null)
return; // Silently ignore...
// Reset the toString() value.
thisString = null;
// Check global cache to see if there're already url loader
// for this url.
URLLoader loader = (URLLoader) urlloaders.get(newUrl);
if (loader == null)
{
String file = newUrl.getFile();
String protocol = newUrl.getProtocol();
// If we have a file: URL, we want to make it absolute
// here, before we decide whether it is really a jar.
URL absoluteURL;
if ("file".equals (protocol))
{
File dir = new File(file);
URL absUrl;
try
{
absoluteURL = dir.getCanonicalFile().toURL();
}
catch (IOException ignore)
{
try
{
absoluteURL = dir.getAbsoluteFile().toURL();
}
catch (MalformedURLException _)
{
// This really should not happen.
absoluteURL = newUrl;
}
}
}
else
{
// This doesn't hurt, and it simplifies the logic a
// little.
absoluteURL = newUrl;
}
// Check that it is not a directory
if ("gcjlib".equals(protocol))
loader = new SoURLLoader(this, newUrl);
else if (! (file.endsWith("/") || file.endsWith(File.separator)))
loader = new JarURLLoader(this, newUrl, absoluteURL);
else if ("file".equals(protocol))
loader = new FileURLLoader(this, newUrl, absoluteURL);
else if ("core".equals(protocol))
loader = new CoreURLLoader(this, newUrl);
else
loader = new RemoteURLLoader(this, newUrl);
// Cache it.
urlloaders.put(newUrl, loader);
}
urlinfos.add(loader);
Vector extraUrls = loader.getClassPath();
if (extraUrls != null)
{
Iterator it = extraUrls.iterator();
while (it.hasNext())
{
URL url = (URL)it.next();
URLLoader extraLoader = (URLLoader) urlloaders.get(url);
if (! urlinfos.contains (extraLoader))
addURLImpl(url);
}
}
}
}
/**
* Adds an array of new locations to the end of the internal URL
* store. Called from the the constructors. Should not call to the
* protected addURL() method since that can be overridden and
* subclasses are not yet in a good state at this point.
* jboss 4.0.3 for example depends on this.
*
* @param newUrls the locations to add
*/
private void addURLs(URL[] newUrls)
{
for (int i = 0; i < newUrls.length; i++)
{
urls.add(newUrls[i]);
addURLImpl(newUrls[i]);
}
}
/**
* Look in both Attributes for a given value. The first Attributes
* object, if not null, has precedence.
*/
private String getAttributeValue(Attributes.Name name, Attributes first,
Attributes second)
{
String result = null;
if (first != null)
result = first.getValue(name);
if (result == null)
result = second.getValue(name);
return result;
}
/**
* Defines a Package based on the given name and the supplied manifest
* information. The manifest indicates the title, version and
* vendor information of the specification and implementation and whether the
* package is sealed. If the Manifest indicates that the package is sealed
* then the Package will be sealed with respect to the supplied URL.
*
* @param name The name of the package
* @param manifest The manifest describing the specification,
* implementation and sealing details of the package
* @param url the code source url to seal the package
* @return the defined Package
* @throws IllegalArgumentException If this package name already exists
* in this class loader
*/
protected Package definePackage(String name, Manifest manifest, URL url)
throws IllegalArgumentException
{
// Compute the name of the package as it may appear in the
// Manifest.
StringBuffer xform = new StringBuffer(name);
for (int i = xform.length () - 1; i >= 0; --i)
if (xform.charAt(i) == '.')
xform.setCharAt(i, '/');
xform.append('/');
String xformName = xform.toString();
Attributes entryAttr = manifest.getAttributes(xformName);
Attributes attr = manifest.getMainAttributes();
String specTitle
= getAttributeValue(Attributes.Name.SPECIFICATION_TITLE,
entryAttr, attr);
String specVersion
= getAttributeValue(Attributes.Name.SPECIFICATION_VERSION,
entryAttr, attr);
String specVendor
= getAttributeValue(Attributes.Name.SPECIFICATION_VENDOR,
entryAttr, attr);
String implTitle
= getAttributeValue(Attributes.Name.IMPLEMENTATION_TITLE,
entryAttr, attr);
String implVersion
= getAttributeValue(Attributes.Name.IMPLEMENTATION_VERSION,
entryAttr, attr);
String implVendor
= getAttributeValue(Attributes.Name.IMPLEMENTATION_VENDOR,
entryAttr, attr);
// Look if the Manifest indicates that this package is sealed
// XXX - most likely not completely correct!
// Shouldn't we also check the sealed attribute of the complete jar?
// http://java.sun.com/products/jdk/1.4/docs/guide/extensions/spec.html#bundled
// But how do we get that jar manifest here?
String sealed = attr.getValue(Attributes.Name.SEALED);
if ("false".equals(sealed))
// make sure that the URL is null so the package is not sealed
url = null;
return definePackage(name,
specTitle, specVendor, specVersion,
implTitle, implVendor, implVersion,
url);
}
/**
* Finds (the first) class by name from one of the locations. The locations
* are searched in the order they were added to the URLClassLoader.
*
* @param className the classname to find
* @exception ClassNotFoundException when the class could not be found or
* loaded
* @return a Class object representing the found class
*/
protected Class findClass(final String className)
throws ClassNotFoundException
{
// Just try to find the resource by the (almost) same name
String resourceName = className.replace('.', '/') + ".class";
int max = urlinfos.size();
Resource resource = null;
for (int i = 0; i < max && resource == null; i++)
{
URLLoader loader = (URLLoader)urlinfos.elementAt(i);
if (loader == null)
continue;
Class k = loader.getClass(className);
if (k != null)
return k;
resource = loader.getResource(resourceName);
}
if (resource == null)
{
String message = className + " not found";
if (runtimeInitialized())
message += " in " + this;
throw new ClassNotFoundException(message);
}
// Try to read the class data, create the CodeSource, Package and
// construct the class (and watch out for those nasty IOExceptions)
try
{
byte[] data;
InputStream in = resource.getInputStream();
try
{
int length = resource.getLength();
if (length != -1)
{
// We know the length of the data.
// Just try to read it in all at once
data = new byte[length];
int pos = 0;
while (length - pos > 0)
{
int len = in.read(data, pos, length - pos);
if (len == -1)
throw new EOFException("Not enough data reading from: "
+ in);
pos += len;
}
}
else
{
// We don't know the data length.
// Have to read it in chunks.
ByteArrayOutputStream out = new ByteArrayOutputStream(4096);
byte[] b = new byte[4096];
int l = 0;
while (l != -1)
{
l = in.read(b);
if (l != -1)
out.write(b, 0, l);
}
data = out.toByteArray();
}
}
finally
{
in.close();
}
final byte[] classData = data;
// Now get the CodeSource
final CodeSource source = resource.getCodeSource();
// Find out package name
String packageName = null;
int lastDot = className.lastIndexOf('.');
if (lastDot != -1)
packageName = className.substring(0, lastDot);
if (packageName != null && getPackage(packageName) == null)
{
// define the package
Manifest manifest = resource.loader.getManifest();
if (manifest == null)
definePackage(packageName, null, null, null, null, null, null,
null);
else
definePackage(packageName, manifest, resource.loader.baseURL);
}
// And finally construct the class!
SecurityManager sm = System.getSecurityManager();
Class result = null;
if (sm != null && securityContext != null)
{
result = (Class)AccessController.doPrivileged
(new PrivilegedAction()
{
public Object run()
{
return defineClass(className, classData,
0, classData.length,
source);
}
}, securityContext);
}
else
result = defineClass(className, classData, 0, classData.length, source);
// Avoid NullPointerExceptions.
Certificate[] resourceCertificates = resource.getCertificates();
if(resourceCertificates != null)
super.setSigners(result, resourceCertificates);
return result;
}
catch (IOException ioe)
{
ClassNotFoundException cnfe;
cnfe = new ClassNotFoundException(className + " not found in " + this);
cnfe.initCause(ioe);
throw cnfe;
}
}
// Cached String representation of this URLClassLoader
private String thisString;
/**
* Returns a String representation of this URLClassLoader giving the
* actual Class name, the URLs that are searched and the parent
* ClassLoader.
*/
public String toString()
{
synchronized (this)
{
if (thisString == null)
{
StringBuffer sb = new StringBuffer();
sb.append(this.getClass().getName());
sb.append("{urls=[" );
URL[] thisURLs = getURLs();
for (int i = 0; i < thisURLs.length; i++)
{
sb.append(thisURLs[i]);
if (i < thisURLs.length - 1)
sb.append(',');
}
sb.append(']');
sb.append(", parent=");
sb.append(getParent());
sb.append('}');
thisString = sb.toString();
}
return thisString;
}
}
/**
* Finds the first occurrence of a resource that can be found. The locations
* are searched in the order they were added to the URLClassLoader.
*
* @param resourceName the resource name to look for
* @return the URLResource for the resource if found, null otherwise
*/
private Resource findURLResource(String resourceName)
{
int max = urlinfos.size();
for (int i = 0; i < max; i++)
{
URLLoader loader = (URLLoader) urlinfos.elementAt(i);
if (loader == null)
continue;
Resource resource = loader.getResource(resourceName);
if (resource != null)
return resource;
}
return null;
}
/**
* Finds the first occurrence of a resource that can be found.
*
* @param resourceName the resource name to look for
* @return the URL if found, null otherwise
*/
public URL findResource(String resourceName)
{
Resource resource = findURLResource(resourceName);
if (resource != null)
return resource.getURL();
// Resource not found
return null;
}
/**
* If the URLStreamHandlerFactory has been set this return the appropriate
* URLStreamHandler for the given protocol, if not set returns null.
*
* @param protocol the protocol for which we need a URLStreamHandler
* @return the appropriate URLStreamHandler or null
*/
URLStreamHandler getURLStreamHandler(String protocol)
{
if (factory == null)
return null;
URLStreamHandler handler;
synchronized (factoryCache)
{
// Check if there're handler for the same protocol in cache.
HashMap cache = (HashMap) factoryCache.get(factory);
handler = (URLStreamHandler) cache.get(protocol);
if (handler == null)
{
// Add it to cache.
handler = factory.createURLStreamHandler(protocol);
cache.put(protocol, handler);
}
}
return handler;
}
/**
* Finds all the resources with a particular name from all the locations.
*
* @param resourceName the name of the resource to lookup
* @return a (possible empty) enumeration of URLs where the resource can be
* found
* @exception IOException when an error occurs accessing one of the
* locations
*/
public Enumeration findResources(String resourceName)
throws IOException
{
Vector resources = new Vector();
int max = urlinfos.size();
for (int i = 0; i < max; i++)
{
URLLoader loader = (URLLoader) urlinfos.elementAt(i);
Resource resource = loader.getResource(resourceName);
if (resource != null)
resources.add(resource.getURL());
}
return resources.elements();
}
/**
* Returns the permissions needed to access a particular code
* source. These permissions includes those returned by
* SecureClassLoader.getPermissions() and the actual
* permissions to access the objects referenced by the URL of the
* code source. The extra permissions added depend on the protocol
* and file portion of the URL in the code source. If the URL has
* the "file" protocol ends with a '/' character then it must be a
* directory and a file Permission to read everything in that
* directory and all subdirectories is added. If the URL had the
* "file" protocol and doesn't end with a '/' character then it must
* be a normal file and a file permission to read that file is
* added. If the URL has any other protocol then a
* socket permission to connect and accept connections from the host
* portion of the URL is added.
*
* @param source The codesource that needs the permissions to be accessed
* @return the collection of permissions needed to access the code resource
* @see java.security.SecureClassLoader#getPermissions(CodeSource)
*/
protected PermissionCollection getPermissions(CodeSource source)
{
// XXX - This implementation does exactly as the Javadoc describes.
// But maybe we should/could use URLConnection.getPermissions()?
// First get the permissions that would normally be granted
PermissionCollection permissions = super.getPermissions(source);
// Now add any extra permissions depending on the URL location.
URL url = source.getLocation();
String protocol = url.getProtocol();
if (protocol.equals("file"))
{
String file = url.getFile();
// If the file end in / it must be an directory.
if (file.endsWith("/") || file.endsWith(File.separator))
{
// Grant permission to read everything in that directory and
// all subdirectories.
permissions.add(new FilePermission(file + "-", "read"));
}
else
{
// It is a 'normal' file.
// Grant permission to access that file.
permissions.add(new FilePermission(file, "read"));
}
}
else
{
// Grant permission to connect to and accept connections from host
String host = url.getHost();
if (host != null)
permissions.add(new SocketPermission(host, "connect,accept"));
}
return permissions;
}
/**
* Returns all the locations that this class loader currently uses the
* resolve classes and resource. This includes both the initially supplied
* URLs as any URLs added later by the loader.
* @return All the currently used URLs
*/
public URL[] getURLs()
{
return (URL[]) urls.toArray(new URL[urls.size()]);
}
/**
* Creates a new instance of a URLClassLoader that gets
* classes from the supplied URLs. This class loader
* will have as parent the standard system class loader.
*
* @param urls the initial URLs used to resolve classes and
* resources
*
* @return the class loader
*
* @exception SecurityException when the calling code does not have
* permission to access the given URLs
*/
public static URLClassLoader newInstance(URL[] urls)
throws SecurityException
{
return newInstance(urls, null);
}
/**
* Creates a new instance of a URLClassLoader that gets
* classes from the supplied URLs and with the supplied
* loader as parent class loader.
*
* @param urls the initial URLs used to resolve classes and
* resources
* @param parent the parent class loader
*
* @return the class loader
*
* @exception SecurityException when the calling code does not have
* permission to access the given URLs
*/
public static URLClassLoader newInstance(URL[] urls, final ClassLoader parent)
throws SecurityException
{
SecurityManager sm = System.getSecurityManager();
if (sm == null)
return new URLClassLoader(urls, parent);
else
{
final Object securityContext = sm.getSecurityContext();
// XXX - What to do with anything else then an AccessControlContext?
if (! (securityContext instanceof AccessControlContext))
throw new SecurityException("securityContext must be AccessControlContext: "
+ securityContext);
URLClassLoader loader =
(URLClassLoader) AccessController.doPrivileged(new PrivilegedAction()
{
public Object run()
{
return new URLClassLoader(parent,
(AccessControlContext) securityContext);
}
});
loader.addURLs(urls);
return loader;
}
}
/**
* Tell whether runtime initialization is complete.
*
* @return whether runtime initialization is complete.
*/
private static native boolean runtimeInitialized();
}