diff options
Diffstat (limited to 'libjava/classpath/java/lang/ClassLoader.java')
| -rw-r--r-- | libjava/classpath/java/lang/ClassLoader.java | 1116 |
1 files changed, 1116 insertions, 0 deletions
diff --git a/libjava/classpath/java/lang/ClassLoader.java b/libjava/classpath/java/lang/ClassLoader.java new file mode 100644 index 00000000000..b644511cf27 --- /dev/null +++ b/libjava/classpath/java/lang/ClassLoader.java @@ -0,0 +1,1116 @@ +/* ClassLoader.java -- responsible for loading classes into the VM + Copyright (C) 1998, 1999, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + + +package java.lang; + +import gnu.classpath.SystemProperties; +import gnu.classpath.VMStackWalker; +import gnu.java.util.DoubleEnumeration; +import gnu.java.util.EmptyEnumeration; + +import java.io.File; +import java.io.IOException; +import java.io.InputStream; +import java.lang.reflect.Constructor; +import java.net.URL; +import java.net.URLClassLoader; +import java.security.CodeSource; +import java.security.PermissionCollection; +import java.security.Policy; +import java.security.ProtectionDomain; +import java.util.ArrayList; +import java.util.Enumeration; +import java.util.HashMap; +import java.util.Map; +import java.util.StringTokenizer; + +/** + * The ClassLoader is a way of customizing the way Java gets its classes + * and loads them into memory. The verifier and other standard Java things + * still run, but the ClassLoader is allowed great flexibility in determining + * where to get the classfiles and when to load and resolve them. For that + * matter, a custom ClassLoader can perform on-the-fly code generation or + * modification! + * + * <p>Every classloader has a parent classloader that is consulted before + * the 'child' classloader when classes or resources should be loaded. + * This is done to make sure that classes can be loaded from an hierarchy of + * multiple classloaders and classloaders do not accidentially redefine + * already loaded classes by classloaders higher in the hierarchy. + * + * <p>The grandparent of all classloaders is the bootstrap classloader, which + * loads all the standard system classes as implemented by GNU Classpath. The + * other special classloader is the system classloader (also called + * application classloader) that loads all classes from the CLASSPATH + * (<code>java.class.path</code> system property). The system classloader + * is responsible for finding the application classes from the classpath, + * and delegates all requests for the standard library classes to its parent + * the bootstrap classloader. Most programs will load all their classes + * through the system classloaders. + * + * <p>The bootstrap classloader in GNU Classpath is implemented as a couple of + * static (native) methods on the package private class + * <code>java.lang.VMClassLoader</code>, the system classloader is an + * anonymous inner class of ClassLoader and a subclass of + * <code>java.net.URLClassLoader</code>. + * + * <p>Users of a <code>ClassLoader</code> will normally just use the methods + * <ul> + * <li> <code>loadClass()</code> to load a class.</li> + * <li> <code>getResource()</code> or <code>getResourceAsStream()</code> + * to access a resource.</li> + * <li> <code>getResources()</code> to get an Enumeration of URLs to all + * the resources provided by the classloader and its parents with the + * same name.</li> + * </ul> + * + * <p>Subclasses should implement the methods + * <ul> + * <li> <code>findClass()</code> which is called by <code>loadClass()</code> + * when the parent classloader cannot provide a named class.</li> + * <li> <code>findResource()</code> which is called by + * <code>getResource()</code> when the parent classloader cannot provide + * a named resource.</li> + * <li> <code>findResources()</code> which is called by + * <code>getResource()</code> to combine all the resources with the + * same name from the classloader and its parents.</li> + * <li> <code>findLibrary()</code> which is called by + * <code>Runtime.loadLibrary()</code> when a class defined by the + * classloader wants to load a native library.</li> + * </ul> + * + * @author John Keiser + * @author Mark Wielaard + * @author Eric Blake (ebb9@email.byu.edu) + * @see Class + * @since 1.0 + * @status still missing 1.4 functionality + */ +public abstract class ClassLoader +{ + /** + * All classes loaded by this classloader. VM's may choose to implement + * this cache natively; but it is here available for use if necessary. It + * is not private in order to allow native code (and trusted subclasses) + * access to this field. + */ + final HashMap loadedClasses = new HashMap(); + + /** + * All packages defined by this classloader. It is not private in order to + * allow native code (and trusted subclasses) access to this field. + */ + final HashMap definedPackages = new HashMap(); + + /** + * The classloader that is consulted before this classloader. + * If null then the parent is the bootstrap classloader. + */ + private final ClassLoader parent; + + /** + * This is true if this classloader was successfully initialized. + * This flag is needed to avoid a class loader attack: even if the + * security manager rejects an attempt to create a class loader, the + * malicious class could have a finalize method which proceeds to + * define classes. + */ + private final boolean initialized; + + static class StaticData + { + /** + * The System Class Loader (a.k.a. Application Class Loader). The one + * returned by ClassLoader.getSystemClassLoader. + */ + static final ClassLoader systemClassLoader = + VMClassLoader.getSystemClassLoader(); + static + { + // Find out if we have to install a default security manager. Note that + // this is done here because we potentially need the system class loader + // to load the security manager and note also that we don't need the + // security manager until the system class loader is created. + // If the runtime chooses to use a class loader that doesn't have the + // system class loader as its parent, it is responsible for setting + // up a security manager before doing so. + String secman = SystemProperties.getProperty("java.security.manager"); + if (secman != null && SecurityManager.current == null) + { + if (secman.equals("") || secman.equals("default")) + { + SecurityManager.current = new SecurityManager(); + } + else + { + try + { + Class cl = Class.forName(secman, false, StaticData.systemClassLoader); + SecurityManager.current = (SecurityManager)cl.newInstance(); + } + catch (Exception x) + { + throw (InternalError) + new InternalError("Unable to create SecurityManager") + .initCause(x); + } + } + } + } + + /** + * The default protection domain, used when defining a class with a null + * parameter for the domain. + */ + static final ProtectionDomain defaultProtectionDomain; + static + { + CodeSource cs = new CodeSource(null, null); + PermissionCollection perm = Policy.getPolicy().getPermissions(cs); + defaultProtectionDomain = new ProtectionDomain(cs, perm); + } + /** + * The command-line state of the package assertion status overrides. This + * map is never modified, so it does not need to be synchronized. + */ + // Package visible for use by Class. + static final Map systemPackageAssertionStatus + = VMClassLoader.packageAssertionStatus(); + /** + * The command-line state of the class assertion status overrides. This + * map is never modified, so it does not need to be synchronized. + */ + // Package visible for use by Class. + static final Map systemClassAssertionStatus + = VMClassLoader.classAssertionStatus(); + } + + /** + * The desired assertion status of classes loaded by this loader, if not + * overridden by package or class instructions. + */ + // Package visible for use by Class. + boolean defaultAssertionStatus = VMClassLoader.defaultAssertionStatus(); + + /** + * The map of package assertion status overrides, or null if no package + * overrides have been specified yet. The values of the map should be + * Boolean.TRUE or Boolean.FALSE, and the unnamed package is represented + * by the null key. This map must be synchronized on this instance. + */ + // Package visible for use by Class. + Map packageAssertionStatus; + + /** + * The map of class assertion status overrides, or null if no class + * overrides have been specified yet. The values of the map should be + * Boolean.TRUE or Boolean.FALSE. This map must be synchronized on this + * instance. + */ + // Package visible for use by Class. + Map classAssertionStatus; + + /** + * VM private data. + */ + transient Object vmdata; + + /** + * Create a new ClassLoader with as parent the system classloader. There + * may be a security check for <code>checkCreateClassLoader</code>. + * + * @throws SecurityException if the security check fails + */ + protected ClassLoader() throws SecurityException + { + this(StaticData.systemClassLoader); + } + + /** + * Create a new ClassLoader with the specified parent. The parent will + * be consulted when a class or resource is requested through + * <code>loadClass()</code> or <code>getResource()</code>. Only when the + * parent classloader cannot provide the requested class or resource the + * <code>findClass()</code> or <code>findResource()</code> method + * of this classloader will be called. There may be a security check for + * <code>checkCreateClassLoader</code>. + * + * @param parent the classloader's parent, or null for the bootstrap + * classloader + * @throws SecurityException if the security check fails + * @since 1.2 + */ + protected ClassLoader(ClassLoader parent) + { + // May we create a new classloader? + SecurityManager sm = SecurityManager.current; + if (sm != null) + sm.checkCreateClassLoader(); + this.parent = parent; + this.initialized = true; + } + + /** + * Load a class using this ClassLoader or its parent, without resolving + * it. Calls <code>loadClass(name, false)</code>. + * + * <p>Subclasses should not override this method but should override + * <code>findClass()</code> which is called by this method.</p> + * + * @param name the name of the class relative to this ClassLoader + * @return the loaded class + * @throws ClassNotFoundException if the class cannot be found + */ + public Class loadClass(String name) throws ClassNotFoundException + { + return loadClass(name, false); + } + + /** + * Load a class using this ClassLoader or its parent, possibly resolving + * it as well using <code>resolveClass()</code>. It first tries to find + * out if the class has already been loaded through this classloader by + * calling <code>findLoadedClass()</code>. Then it calls + * <code>loadClass()</code> on the parent classloader (or when there is + * no parent it uses the VM bootclassloader). If the class is still + * not loaded it tries to create a new class by calling + * <code>findClass()</code>. Finally when <code>resolve</code> is + * <code>true</code> it also calls <code>resolveClass()</code> on the + * newly loaded class. + * + * <p>Subclasses should not override this method but should override + * <code>findClass()</code> which is called by this method.</p> + * + * @param name the fully qualified name of the class to load + * @param resolve whether or not to resolve the class + * @return the loaded class + * @throws ClassNotFoundException if the class cannot be found + */ + protected synchronized Class loadClass(String name, boolean resolve) + throws ClassNotFoundException + { + // Have we already loaded this class? + Class c = findLoadedClass(name); + if (c == null) + { + // Can the class be loaded by a parent? + try + { + if (parent == null) + { + c = VMClassLoader.loadClass(name, resolve); + if (c != null) + return c; + } + else + { + return parent.loadClass(name, resolve); + } + } + catch (ClassNotFoundException e) + { + } + // Still not found, we have to do it ourself. + c = findClass(name); + } + if (resolve) + resolveClass(c); + return c; + } + + /** + * Called for every class name that is needed but has not yet been + * defined by this classloader or one of its parents. It is called by + * <code>loadClass()</code> after both <code>findLoadedClass()</code> and + * <code>parent.loadClass()</code> couldn't provide the requested class. + * + * <p>The default implementation throws a + * <code>ClassNotFoundException</code>. Subclasses should override this + * method. An implementation of this method in a subclass should get the + * class bytes of the class (if it can find them), if the package of the + * requested class doesn't exist it should define the package and finally + * it should call define the actual class. It does not have to resolve the + * class. It should look something like the following:<br> + * + * <pre> + * // Get the bytes that describe the requested class + * byte[] classBytes = classLoaderSpecificWayToFindClassBytes(name); + * // Get the package name + * int lastDot = name.lastIndexOf('.'); + * if (lastDot != -1) + * { + * String packageName = name.substring(0, lastDot); + * // Look if the package already exists + * if (getPackage(packageName) == null) + * { + * // define the package + * definePackage(packageName, ...); + * } + * } + * // Define and return the class + * return defineClass(name, classBytes, 0, classBytes.length); + * </pre> + * + * <p><code>loadClass()</code> makes sure that the <code>Class</code> + * returned by <code>findClass()</code> will later be returned by + * <code>findLoadedClass()</code> when the same class name is requested. + * + * @param name class name to find (including the package name) + * @return the requested Class + * @throws ClassNotFoundException when the class can not be found + * @since 1.2 + */ + protected Class findClass(String name) throws ClassNotFoundException + { + throw new ClassNotFoundException(name); + } + + /** + * Helper to define a class using a string of bytes. This version is not + * secure. + * + * @param data the data representing the classfile, in classfile format + * @param offset the offset into the data where the classfile starts + * @param len the length of the classfile data in the array + * @return the class that was defined + * @throws ClassFormatError if data is not in proper classfile format + * @throws IndexOutOfBoundsException if offset or len is negative, or + * offset + len exceeds data + * @deprecated use {@link #defineClass(String, byte[], int, int)} instead + */ + protected final Class defineClass(byte[] data, int offset, int len) + throws ClassFormatError + { + return defineClass(null, data, offset, len); + } + + /** + * Helper to define a class using a string of bytes without a + * ProtectionDomain. Subclasses should call this method from their + * <code>findClass()</code> implementation. The name should use '.' + * separators, and discard the trailing ".class". The default protection + * domain has the permissions of + * <code>Policy.getPolicy().getPermissions(new CodeSource(null, null))</code>. + * + * @param name the name to give the class, or null if unknown + * @param data the data representing the classfile, in classfile format + * @param offset the offset into the data where the classfile starts + * @param len the length of the classfile data in the array + * @return the class that was defined + * @throws ClassFormatError if data is not in proper classfile format + * @throws IndexOutOfBoundsException if offset or len is negative, or + * offset + len exceeds data + * @throws SecurityException if name starts with "java." + * @since 1.1 + */ + protected final Class defineClass(String name, byte[] data, int offset, + int len) throws ClassFormatError + { + return defineClass(name, data, offset, len, null); + } + + /** + * Helper to define a class using a string of bytes. Subclasses should call + * this method from their <code>findClass()</code> implementation. If the + * domain is null, the default of + * <code>Policy.getPolicy().getPermissions(new CodeSource(null, null))</code> + * is used. Once a class has been defined in a package, all further classes + * in that package must have the same set of certificates or a + * SecurityException is thrown. + * + * @param name the name to give the class. null if unknown + * @param data the data representing the classfile, in classfile format + * @param offset the offset into the data where the classfile starts + * @param len the length of the classfile data in the array + * @param domain the ProtectionDomain to give to the class, null for the + * default protection domain + * @return the class that was defined + * @throws ClassFormatError if data is not in proper classfile format + * @throws IndexOutOfBoundsException if offset or len is negative, or + * offset + len exceeds data + * @throws SecurityException if name starts with "java.", or if certificates + * do not match up + * @since 1.2 + */ + protected final synchronized Class defineClass(String name, byte[] data, + int offset, int len, + ProtectionDomain domain) + throws ClassFormatError + { + if (domain == null) + domain = StaticData.defaultProtectionDomain; + if (! initialized) + throw new SecurityException("attempt to define class from uninitialized class loader"); + + Class retval = VMClassLoader.defineClass(this, name, data, + offset, len, domain); + loadedClasses.put(retval.getName(), retval); + return retval; + } + + /** + * Links the class, if that has not already been done. Linking basically + * resolves all references to other classes made by this class. + * + * @param c the class to resolve + * @throws NullPointerException if c is null + * @throws LinkageError if linking fails + */ + protected final void resolveClass(Class c) + { + VMClassLoader.resolveClass(c); + } + + /** + * Helper to find a Class using the system classloader, possibly loading it. + * A subclass usually does not need to call this, if it correctly + * overrides <code>findClass(String)</code>. + * + * @param name the name of the class to find + * @return the found class + * @throws ClassNotFoundException if the class cannot be found + */ + protected final Class findSystemClass(String name) + throws ClassNotFoundException + { + return Class.forName(name, false, StaticData.systemClassLoader); + } + + /** + * Returns the parent of this classloader. If the parent of this + * classloader is the bootstrap classloader then this method returns + * <code>null</code>. A security check may be performed on + * <code>RuntimePermission("getClassLoader")</code>. + * + * @return the parent <code>ClassLoader</code> + * @throws SecurityException if the security check fails + * @since 1.2 + */ + public final ClassLoader getParent() + { + // Check if we may return the parent classloader. + SecurityManager sm = SecurityManager.current; + if (sm != null) + { + ClassLoader cl = VMStackWalker.getCallingClassLoader(); + if (cl != null && ! cl.isAncestorOf(this)) + sm.checkPermission(new RuntimePermission("getClassLoader")); + } + return parent; + } + + /** + * Helper to set the signers of a class. This should be called after + * defining the class. + * + * @param c the Class to set signers of + * @param signers the signers to set + * @since 1.1 + */ + protected final void setSigners(Class c, Object[] signers) + { + c.setSigners(signers); + } + + /** + * Helper to find an already-loaded class in this ClassLoader. + * + * @param name the name of the class to find + * @return the found Class, or null if it is not found + * @since 1.1 + */ + protected final synchronized Class findLoadedClass(String name) + { + // NOTE: If the VM is keeping its own cache, it may make sense to have + // this method be native. + return (Class) loadedClasses.get(name); + } + + /** + * Get the URL to a resource using this classloader or one of its parents. + * First tries to get the resource by calling <code>getResource()</code> + * on the parent classloader. If the parent classloader returns null then + * it tries finding the resource by calling <code>findResource()</code> on + * this classloader. The resource name should be separated by '/' for path + * elements. + * + * <p>Subclasses should not override this method but should override + * <code>findResource()</code> which is called by this method. + * + * @param name the name of the resource relative to this classloader + * @return the URL to the resource or null when not found + */ + public URL getResource(String name) + { + URL result; + + if (parent == null) + result = VMClassLoader.getResource(name); + else + result = parent.getResource(name); + + if (result == null) + result = findResource(name); + return result; + } + + /** + * Returns an Enumeration of all resources with a given name that can + * be found by this classloader and its parents. Certain classloaders + * (such as the URLClassLoader when given multiple jar files) can have + * multiple resources with the same name that come from multiple locations. + * It can also occur that a parent classloader offers a resource with a + * certain name and the child classloader also offers a resource with that + * same name. <code>getResource()</code> only offers the first resource (of the + * parent) with a given name. This method lists all resources with the + * same name. The name should use '/' as path separators. + * + * <p>The Enumeration is created by first calling <code>getResources()</code> + * on the parent classloader and then calling <code>findResources()</code> + * on this classloader.</p> + * + * @param name the resource name + * @return an enumaration of all resources found + * @throws IOException if I/O errors occur in the process + * @since 1.2 + */ + public final Enumeration getResources(String name) throws IOException + { + Enumeration parentResources; + if (parent == null) + parentResources = VMClassLoader.getResources(name); + else + parentResources = parent.getResources(name); + return new DoubleEnumeration(parentResources, findResources(name)); + } + + /** + * Called whenever all locations of a named resource are needed. + * It is called by <code>getResources()</code> after it has called + * <code>parent.getResources()</code>. The results are combined by + * the <code>getResources()</code> method. + * + * <p>The default implementation always returns an empty Enumeration. + * Subclasses should override it when they can provide an Enumeration of + * URLs (possibly just one element) to the named resource. + * The first URL of the Enumeration should be the same as the one + * returned by <code>findResource</code>. + * + * @param name the name of the resource to be found + * @return a possibly empty Enumeration of URLs to the named resource + * @throws IOException if I/O errors occur in the process + * @since 1.2 + */ + protected Enumeration findResources(String name) throws IOException + { + return EmptyEnumeration.getInstance(); + } + + /** + * Called whenever a resource is needed that could not be provided by + * one of the parents of this classloader. It is called by + * <code>getResource()</code> after <code>parent.getResource()</code> + * couldn't provide the requested resource. + * + * <p>The default implementation always returns null. Subclasses should + * override this method when they can provide a way to return a URL + * to a named resource. + * + * @param name the name of the resource to be found + * @return a URL to the named resource or null when not found + * @since 1.2 + */ + protected URL findResource(String name) + { + return null; + } + + /** + * Get the URL to a resource using the system classloader. + * + * @param name the name of the resource relative to the system classloader + * @return the URL to the resource + * @since 1.1 + */ + public static final URL getSystemResource(String name) + { + return StaticData.systemClassLoader.getResource(name); + } + + /** + * Get an Enumeration of URLs to resources with a given name using the + * the system classloader. The enumeration firsts lists the resources with + * the given name that can be found by the bootstrap classloader followed + * by the resources with the given name that can be found on the classpath. + * + * @param name the name of the resource relative to the system classloader + * @return an Enumeration of URLs to the resources + * @throws IOException if I/O errors occur in the process + * @since 1.2 + */ + public static Enumeration getSystemResources(String name) throws IOException + { + return StaticData.systemClassLoader.getResources(name); + } + + /** + * Get a resource as stream using this classloader or one of its parents. + * First calls <code>getResource()</code> and if that returns a URL to + * the resource then it calls and returns the InputStream given by + * <code>URL.openStream()</code>. + * + * <p>Subclasses should not override this method but should override + * <code>findResource()</code> which is called by this method. + * + * @param name the name of the resource relative to this classloader + * @return an InputStream to the resource, or null + * @since 1.1 + */ + public InputStream getResourceAsStream(String name) + { + try + { + URL url = getResource(name); + if (url == null) + return null; + return url.openStream(); + } + catch (IOException e) + { + return null; + } + } + + /** + * Get a resource using the system classloader. + * + * @param name the name of the resource relative to the system classloader + * @return an input stream for the resource, or null + * @since 1.1 + */ + public static final InputStream getSystemResourceAsStream(String name) + { + try + { + URL url = getSystemResource(name); + if (url == null) + return null; + return url.openStream(); + } + catch (IOException e) + { + return null; + } + } + + /** + * Returns the system classloader. The system classloader (also called + * the application classloader) is the classloader that is used to + * load the application classes on the classpath (given by the system + * property <code>java.class.path</code>. This is set as the context + * class loader for a thread. The system property + * <code>java.system.class.loader</code>, if defined, is taken to be the + * name of the class to use as the system class loader, which must have + * a public constructor which takes a ClassLoader as a parent. The parent + * class loader passed in the constructor is the default system class + * loader. + * + * <p>Note that this is different from the bootstrap classloader that + * actually loads all the real "system" classes. + * + * <p>A security check will be performed for + * <code>RuntimePermission("getClassLoader")</code> if the calling class + * is not a parent of the system class loader. + * + * @return the system class loader + * @throws SecurityException if the security check fails + * @throws IllegalStateException if this is called recursively + * @throws Error if <code>java.system.class.loader</code> fails to load + * @since 1.2 + */ + public static ClassLoader getSystemClassLoader() + { + // Check if we may return the system classloader + SecurityManager sm = SecurityManager.current; + if (sm != null) + { + ClassLoader cl = VMStackWalker.getCallingClassLoader(); + if (cl != null && cl != StaticData.systemClassLoader) + sm.checkPermission(new RuntimePermission("getClassLoader")); + } + + return StaticData.systemClassLoader; + } + + /** + * Defines a new package and creates a Package object. The package should + * be defined before any class in the package is defined with + * <code>defineClass()</code>. The package should not yet be defined + * before in this classloader or in one of its parents (which means that + * <code>getPackage()</code> should return <code>null</code>). All + * parameters except the <code>name</code> of the package may be + * <code>null</code>. + * + * <p>Subclasses should call this method from their <code>findClass()</code> + * implementation before calling <code>defineClass()</code> on a Class + * in a not yet defined Package (which can be checked by calling + * <code>getPackage()</code>). + * + * @param name the name of the Package + * @param specTitle the name of the specification + * @param specVendor the name of the specification designer + * @param specVersion the version of this specification + * @param implTitle the name of the implementation + * @param implVendor the vendor that wrote this implementation + * @param implVersion the version of this implementation + * @param sealed if sealed the origin of the package classes + * @return the Package object for the specified package + * @throws IllegalArgumentException if the package name is null or it + * was already defined by this classloader or one of its parents + * @see Package + * @since 1.2 + */ + protected Package definePackage(String name, String specTitle, + String specVendor, String specVersion, + String implTitle, String implVendor, + String implVersion, URL sealed) + { + if (getPackage(name) != null) + throw new IllegalArgumentException("Package " + name + + " already defined"); + Package p = new Package(name, specTitle, specVendor, specVersion, + implTitle, implVendor, implVersion, sealed); + synchronized (definedPackages) + { + definedPackages.put(name, p); + } + return p; + } + + /** + * Returns the Package object for the requested package name. It returns + * null when the package is not defined by this classloader or one of its + * parents. + * + * @param name the package name to find + * @return the package, if defined + * @since 1.2 + */ + protected Package getPackage(String name) + { + Package p; + if (parent == null) + p = VMClassLoader.getPackage(name); + else + p = parent.getPackage(name); + + if (p == null) + { + synchronized (definedPackages) + { + p = (Package) definedPackages.get(name); + } + } + return p; + } + + /** + * Returns all Package objects defined by this classloader and its parents. + * + * @return an array of all defined packages + * @since 1.2 + */ + protected Package[] getPackages() + { + // Get all our packages. + Package[] packages; + synchronized(definedPackages) + { + packages = new Package[definedPackages.size()]; + definedPackages.values().toArray(packages); + } + + // If we have a parent get all packages defined by our parents. + Package[] parentPackages; + if (parent == null) + parentPackages = VMClassLoader.getPackages(); + else + parentPackages = parent.getPackages(); + + Package[] allPackages = new Package[parentPackages.length + + packages.length]; + System.arraycopy(parentPackages, 0, allPackages, 0, + parentPackages.length); + System.arraycopy(packages, 0, allPackages, parentPackages.length, + packages.length); + return allPackages; + } + + /** + * Called by <code>Runtime.loadLibrary()</code> to get an absolute path + * to a (system specific) library that was requested by a class loaded + * by this classloader. The default implementation returns + * <code>null</code>. It should be implemented by subclasses when they + * have a way to find the absolute path to a library. If this method + * returns null the library is searched for in the default locations + * (the directories listed in the <code>java.library.path</code> system + * property). + * + * @param name the (system specific) name of the requested library + * @return the full pathname to the requested library, or null + * @see Runtime#loadLibrary() + * @since 1.2 + */ + protected String findLibrary(String name) + { + return null; + } + + /** + * Set the default assertion status for classes loaded by this classloader, + * used unless overridden by a package or class request. + * + * @param enabled true to set the default to enabled + * @see #setClassAssertionStatus(String, boolean) + * @see #setPackageAssertionStatus(String, boolean) + * @see #clearAssertionStatus() + * @since 1.4 + */ + public void setDefaultAssertionStatus(boolean enabled) + { + defaultAssertionStatus = enabled; + } + + /** + * Set the default assertion status for packages, used unless overridden + * by a class request. This default also covers subpackages, unless they + * are also specified. The unnamed package should use null for the name. + * + * @param name the package (and subpackages) to affect + * @param enabled true to set the default to enabled + * @see #setDefaultAssertionStatus(String, boolean) + * @see #setClassAssertionStatus(String, boolean) + * @see #clearAssertionStatus() + * @since 1.4 + */ + public synchronized void setPackageAssertionStatus(String name, + boolean enabled) + { + if (packageAssertionStatus == null) + packageAssertionStatus + = new HashMap(StaticData.systemPackageAssertionStatus); + packageAssertionStatus.put(name, Boolean.valueOf(enabled)); + } + + /** + * Set the default assertion status for a class. This only affects the + * status of top-level classes, any other string is harmless. + * + * @param name the class to affect + * @param enabled true to set the default to enabled + * @throws NullPointerException if name is null + * @see #setDefaultAssertionStatus(String, boolean) + * @see #setPackageAssertionStatus(String, boolean) + * @see #clearAssertionStatus() + * @since 1.4 + */ + public synchronized void setClassAssertionStatus(String name, + boolean enabled) + { + if (classAssertionStatus == null) + classAssertionStatus = + new HashMap(StaticData.systemClassAssertionStatus); + // The toString() hack catches null, as required. + classAssertionStatus.put(name.toString(), Boolean.valueOf(enabled)); + } + + /** + * Resets the default assertion status of this classloader, its packages + * and classes, all to false. This allows overriding defaults inherited + * from the command line. + * + * @see #setDefaultAssertionStatus(boolean) + * @see #setClassAssertionStatus(String, boolean) + * @see #setPackageAssertionStatus(String, boolean) + * @since 1.4 + */ + public synchronized void clearAssertionStatus() + { + defaultAssertionStatus = false; + packageAssertionStatus = new HashMap(); + classAssertionStatus = new HashMap(); + } + + /** + * Return true if this loader is either the specified class loader + * or an ancestor thereof. + * @param loader the class loader to check + */ + final boolean isAncestorOf(ClassLoader loader) + { + while (loader != null) + { + if (this == loader) + return true; + loader = loader.parent; + } + return false; + } + + private static URL[] getExtClassLoaderUrls() + { + String classpath = SystemProperties.getProperty("java.ext.dirs", ""); + StringTokenizer tok = new StringTokenizer(classpath, File.pathSeparator); + ArrayList list = new ArrayList(); + while (tok.hasMoreTokens()) + { + try + { + File f = new File(tok.nextToken()); + File[] files = f.listFiles(); + if (files != null) + for (int i = 0; i < files.length; i++) + list.add(files[i].toURL()); + } + catch(Exception x) + { + } + } + URL[] urls = new URL[list.size()]; + list.toArray(urls); + return urls; + } + + private static void addFileURL(ArrayList list, String file) + { + try + { + list.add(new File(file).toURL()); + } + catch(java.net.MalformedURLException x) + { + } + } + + private static URL[] getSystemClassLoaderUrls() + { + String classpath = SystemProperties.getProperty("java.class.path", "."); + StringTokenizer tok = new StringTokenizer(classpath, File.pathSeparator, true); + ArrayList list = new ArrayList(); + while (tok.hasMoreTokens()) + { + String s = tok.nextToken(); + if (s.equals(File.pathSeparator)) + addFileURL(list, "."); + else + { + addFileURL(list, s); + if (tok.hasMoreTokens()) + { + // Skip the separator. + tok.nextToken(); + // If the classpath ended with a separator, + // append the current directory. + if (!tok.hasMoreTokens()) + addFileURL(list, "."); + } + } + } + URL[] urls = new URL[list.size()]; + list.toArray(urls); + return urls; + } + + static ClassLoader defaultGetSystemClassLoader() + { + return createAuxiliarySystemClassLoader( + createSystemClassLoader(getSystemClassLoaderUrls(), + createExtClassLoader(getExtClassLoaderUrls(), null))); + } + + static ClassLoader createExtClassLoader(URL[] urls, ClassLoader parent) + { + if (urls.length > 0) + return new URLClassLoader(urls, parent); + else + return parent; + } + + static ClassLoader createSystemClassLoader(URL[] urls, ClassLoader parent) + { + return + new URLClassLoader(urls, parent) + { + protected synchronized Class loadClass(String name, + boolean resolve) + throws ClassNotFoundException + { + SecurityManager sm = SecurityManager.current; + if (sm != null) + { + int lastDot = name.lastIndexOf('.'); + if (lastDot != -1) + sm.checkPackageAccess(name.substring(0, lastDot)); + } + return super.loadClass(name, resolve); + } + }; + } + + static ClassLoader createAuxiliarySystemClassLoader(ClassLoader parent) + { + String loader = SystemProperties.getProperty("java.system.class.loader", null); + if (loader == null) + { + return parent; + } + try + { + Constructor c = Class.forName(loader, false, parent) + .getConstructor(new Class[] { ClassLoader.class }); + return (ClassLoader)c.newInstance(new Object[] { parent }); + } + catch (Exception e) + { + System.err.println("Requested system classloader " + loader + " failed."); + throw (Error) + new Error("Requested system classloader " + loader + " failed.") + .initCause(e); + } + } +} |
