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Diffstat (limited to 'libjava/java/lang/Runtime.java')
| -rw-r--r-- | libjava/java/lang/Runtime.java | 747 |
1 files changed, 0 insertions, 747 deletions
diff --git a/libjava/java/lang/Runtime.java b/libjava/java/lang/Runtime.java deleted file mode 100644 index 3466f19..0000000 --- a/libjava/java/lang/Runtime.java +++ /dev/null @@ -1,747 +0,0 @@ -/* Runtime.java -- access to the VM process - Copyright (C) 1998, 2002, 2003, 2004, 2005, 2006 Free Software Foundation - -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 java.io.File; -import java.io.IOException; -import java.io.InputStream; -import java.io.OutputStream; -import java.util.HashSet; -import java.util.Iterator; -import java.util.Set; -import java.util.StringTokenizer; - -/** - * Runtime represents the Virtual Machine. - * - * @author John Keiser - * @author Eric Blake (ebb9@email.byu.edu) - * @author Jeroen Frijters - */ -// No idea why this class isn't final, since you can't build a subclass! -public class Runtime -{ - /** - * The library path, to search when loading libraries. We can also safely use - * this as a lock for synchronization. - */ - private final String[] libpath; - - static - { - init(); - } - - /** - * The thread that started the exit sequence. Access to this field must - * be thread-safe; lock on libpath to avoid deadlock with user code. - * <code>runFinalization()</code> may want to look at this to see if ALL - * finalizers should be run, because the virtual machine is about to halt. - */ - private Thread exitSequence; - - /** - * All shutdown hooks. This is initialized lazily, and set to null once all - * shutdown hooks have run. Access to this field must be thread-safe; lock - * on libpath to avoid deadlock with user code. - */ - private Set shutdownHooks; - - /** True if we should finalize on exit. */ - private boolean finalizeOnExit; - - /** - * The one and only runtime instance. - */ - private static final Runtime current = new Runtime(); - - /** - * Not instantiable by a user, this should only create one instance. - */ - private Runtime() - { - if (current != null) - throw new InternalError("Attempt to recreate Runtime"); - - // We don't use libpath in the libgcj implementation. We still - // set it to something to allow the various synchronizations to - // work. - libpath = new String[0]; - } - - /** - * Get the current Runtime object for this JVM. This is necessary to access - * the many instance methods of this class. - * - * @return the current Runtime object - */ - public static Runtime getRuntime() - { - return current; - } - - /** - * Exit the Java runtime. This method will either throw a SecurityException - * or it will never return. The status code is returned to the system; often - * a non-zero status code indicates an abnormal exit. Of course, there is a - * security check, <code>checkExit(status)</code>. - * - * <p>First, all shutdown hooks are run, in unspecified order, and - * concurrently. Next, if finalization on exit has been enabled, all pending - * finalizers are run. Finally, the system calls <code>halt</code>.</p> - * - * <p>If this is run a second time after shutdown has already started, there - * are two actions. If shutdown hooks are still executing, it blocks - * indefinitely. Otherwise, if the status is nonzero it halts immediately; - * if it is zero, it blocks indefinitely. This is typically called by - * <code>System.exit</code>.</p> - * - * @param status the status to exit with - * @throws SecurityException if permission is denied - * @see #addShutdownHook(Thread) - * @see #runFinalizersOnExit(boolean) - * @see #runFinalization() - * @see #halt(int) - */ - public void exit(int status) - { - SecurityManager sm = SecurityManager.current; // Be thread-safe! - if (sm != null) - sm.checkExit(status); - exitNoChecks(status); - } - - // Accessor to avoid adding a vtable slot. - static void exitNoChecksAccessor(int status) - { - current.exitNoChecks(status); - } - - // Private since we can't add a vtable slot in 4.1.x. - private void exitNoChecks(int status) - { - if (runShutdownHooks()) - exitInternal(status); - - // Someone else already called runShutdownHooks(). - // Make sure we are not/no longer in the shutdownHooks set. - // And wait till the thread that is calling runShutdownHooks() finishes. - synchronized (libpath) - { - if (shutdownHooks != null) - { - shutdownHooks.remove(Thread.currentThread()); - // Interrupt the exit sequence thread, in case it was waiting - // inside a join on our thread. - exitSequence.interrupt(); - // Shutdown hooks are still running, so we clear status to - // make sure we don't halt. - status = 0; - } - } - - // If exit() is called again after the shutdown hooks have run, but - // while finalization for exit is going on and the status is non-zero - // we halt immediately. - if (status != 0) - exitInternal(status); - - while (true) - try - { - exitSequence.join(); - } - catch (InterruptedException e) - { - // Ignore, we've suspended indefinitely to let all shutdown - // hooks complete, and to let any non-zero exits through, because - // this is a duplicate call to exit(0). - } - } - - /** - * On first invocation, run all the shutdown hooks and return true. - * Any subsequent invocations will simply return false. - * Note that it is package accessible so that VMRuntime can call it - * when VM exit is not triggered by a call to Runtime.exit(). - * - * @return was the current thread the first one to call this method? - */ - boolean runShutdownHooks() - { - boolean first = false; - synchronized (libpath) // Synch on libpath, not this, to avoid deadlock. - { - if (exitSequence == null) - { - first = true; - exitSequence = Thread.currentThread(); - if (shutdownHooks != null) - { - Iterator i = shutdownHooks.iterator(); - while (i.hasNext()) // Start all shutdown hooks. - try - { - ((Thread) i.next()).start(); - } - catch (IllegalThreadStateException e) - { - i.remove(); - } - } - } - } - if (first) - { - if (shutdownHooks != null) - { - // Check progress of all shutdown hooks. As a hook completes, - // remove it from the set. If a hook calls exit, it removes - // itself from the set, then waits indefinitely on the - // exitSequence thread. Once the set is empty, set it to null to - // signal all finalizer threads that halt may be called. - while (true) - { - Thread[] hooks; - synchronized (libpath) - { - hooks = new Thread[shutdownHooks.size()]; - shutdownHooks.toArray(hooks); - } - if (hooks.length == 0) - break; - for (int i = 0; i < hooks.length; i++) - { - try - { - synchronized (libpath) - { - if (!shutdownHooks.contains(hooks[i])) - continue; - } - hooks[i].join(); - synchronized (libpath) - { - shutdownHooks.remove(hooks[i]); - } - } - catch (InterruptedException x) - { - // continue waiting on the next thread - } - } - } - synchronized (libpath) - { - shutdownHooks = null; - } - } - // Run finalization on all finalizable objects (even if they are - // still reachable). - runFinalizationForExit(); - } - return first; - } - - /** - * Register a new shutdown hook. This is invoked when the program exits - * normally (because all non-daemon threads ended, or because - * <code>System.exit</code> was invoked), or when the user terminates - * the virtual machine (such as by typing ^C, or logging off). There is - * a security check to add hooks, - * <code>RuntimePermission("shutdownHooks")</code>. - * - * <p>The hook must be an initialized, but unstarted Thread. The threads - * are run concurrently, and started in an arbitrary order; and user - * threads or daemons may still be running. Once shutdown hooks have - * started, they must all complete, or else you must use <code>halt</code>, - * to actually finish the shutdown sequence. Attempts to modify hooks - * after shutdown has started result in IllegalStateExceptions.</p> - * - * <p>It is imperative that you code shutdown hooks defensively, as you - * do not want to deadlock, and have no idea what other hooks will be - * running concurrently. It is also a good idea to finish quickly, as the - * virtual machine really wants to shut down!</p> - * - * <p>There are no guarantees that such hooks will run, as there are ways - * to forcibly kill a process. But in such a drastic case, shutdown hooks - * would do little for you in the first place.</p> - * - * @param hook an initialized, unstarted Thread - * @throws IllegalArgumentException if the hook is already registered or run - * @throws IllegalStateException if the virtual machine is already in - * the shutdown sequence - * @throws SecurityException if permission is denied - * @since 1.3 - * @see #removeShutdownHook(Thread) - * @see #exit(int) - * @see #halt(int) - */ - public void addShutdownHook(Thread hook) - { - SecurityManager sm = SecurityManager.current; // Be thread-safe! - if (sm != null) - sm.checkPermission(new RuntimePermission("shutdownHooks")); - if (hook.isAlive() || hook.getThreadGroup() == null) - throw new IllegalArgumentException("The hook thread " + hook + " must not have been already run or started"); - synchronized (libpath) - { - if (exitSequence != null) - throw new IllegalStateException("The Virtual Machine is exiting. It is not possible anymore to add any hooks"); - if (shutdownHooks == null) - shutdownHooks = new HashSet(); // Lazy initialization. - if (! shutdownHooks.add(hook)) - throw new IllegalArgumentException(hook.toString() + " had already been inserted"); - } - } - - /** - * De-register a shutdown hook. As when you registered it, there is a - * security check to remove hooks, - * <code>RuntimePermission("shutdownHooks")</code>. - * - * @param hook the hook to remove - * @return true if the hook was successfully removed, false if it was not - * registered in the first place - * @throws IllegalStateException if the virtual machine is already in - * the shutdown sequence - * @throws SecurityException if permission is denied - * @since 1.3 - * @see #addShutdownHook(Thread) - * @see #exit(int) - * @see #halt(int) - */ - public boolean removeShutdownHook(Thread hook) - { - SecurityManager sm = SecurityManager.current; // Be thread-safe! - if (sm != null) - sm.checkPermission(new RuntimePermission("shutdownHooks")); - synchronized (libpath) - { - if (exitSequence != null) - throw new IllegalStateException(); - if (shutdownHooks != null) - return shutdownHooks.remove(hook); - } - return false; - } - - /** - * Forcibly terminate the virtual machine. This call never returns. It is - * much more severe than <code>exit</code>, as it bypasses all shutdown - * hooks and initializers. Use caution in calling this! Of course, there is - * a security check, <code>checkExit(status)</code>. - * - * @param status the status to exit with - * @throws SecurityException if permission is denied - * @since 1.3 - * @see #exit(int) - * @see #addShutdownHook(Thread) - */ - public void halt(int status) - { - SecurityManager sm = SecurityManager.current; // Be thread-safe! - if (sm != null) - sm.checkExit(status); - exitInternal(status); - } - - /** - * Tell the VM to run the finalize() method on every single Object before - * it exits. Note that the JVM may still exit abnormally and not perform - * this, so you still don't have a guarantee. And besides that, this is - * inherently unsafe in multi-threaded code, as it may result in deadlock - * as multiple threads compete to manipulate objects. This value defaults to - * <code>false</code>. There is a security check, <code>checkExit(0)</code>. - * - * @param finalizeOnExit whether to finalize all Objects on exit - * @throws SecurityException if permission is denied - * @see #exit(int) - * @see #gc() - * @since 1.1 - * @deprecated never rely on finalizers to do a clean, thread-safe, - * mop-up from your code - */ - public static void runFinalizersOnExit(boolean finalizeOnExit) - { - SecurityManager sm = SecurityManager.current; // Be thread-safe! - if (sm != null) - sm.checkExit(0); - current.finalizeOnExit = finalizeOnExit; - } - - /** - * Create a new subprocess with the specified command line. Calls - * <code>exec(cmdline, null, null)</code>. A security check is performed, - * <code>checkExec</code>. - * - * @param cmdline the command to call - * @return the Process object - * @throws SecurityException if permission is denied - * @throws IOException if an I/O error occurs - * @throws NullPointerException if cmdline is null - * @throws IndexOutOfBoundsException if cmdline is "" - */ - public Process exec(String cmdline) throws IOException - { - return exec(cmdline, null, null); - } - - /** - * Create a new subprocess with the specified command line and environment. - * If the environment is null, the process inherits the environment of - * this process. Calls <code>exec(cmdline, env, null)</code>. A security - * check is performed, <code>checkExec</code>. - * - * @param cmdline the command to call - * @param env the environment to use, in the format name=value - * @return the Process object - * @throws SecurityException if permission is denied - * @throws IOException if an I/O error occurs - * @throws NullPointerException if cmdline is null, or env has null entries - * @throws IndexOutOfBoundsException if cmdline is "" - */ - public Process exec(String cmdline, String[] env) throws IOException - { - return exec(cmdline, env, null); - } - - /** - * Create a new subprocess with the specified command line, environment, and - * working directory. If the environment is null, the process inherits the - * environment of this process. If the directory is null, the process uses - * the current working directory. This splits cmdline into an array, using - * the default StringTokenizer, then calls - * <code>exec(cmdArray, env, dir)</code>. A security check is performed, - * <code>checkExec</code>. - * - * @param cmdline the command to call - * @param env the environment to use, in the format name=value - * @param dir the working directory to use - * @return the Process object - * @throws SecurityException if permission is denied - * @throws IOException if an I/O error occurs - * @throws NullPointerException if cmdline is null, or env has null entries - * @throws IndexOutOfBoundsException if cmdline is "" - * @since 1.3 - */ - public Process exec(String cmdline, String[] env, File dir) - throws IOException - { - StringTokenizer t = new StringTokenizer(cmdline); - String[] cmd = new String[t.countTokens()]; - for (int i = 0; i < cmd.length; i++) - cmd[i] = t.nextToken(); - return exec(cmd, env, dir); - } - - /** - * Create a new subprocess with the specified command line, already - * tokenized. Calls <code>exec(cmd, null, null)</code>. A security check - * is performed, <code>checkExec</code>. - * - * @param cmd the command to call - * @return the Process object - * @throws SecurityException if permission is denied - * @throws IOException if an I/O error occurs - * @throws NullPointerException if cmd is null, or has null entries - * @throws IndexOutOfBoundsException if cmd is length 0 - */ - public Process exec(String[] cmd) throws IOException - { - return exec(cmd, null, null); - } - - /** - * Create a new subprocess with the specified command line, already - * tokenized, and specified environment. If the environment is null, the - * process inherits the environment of this process. Calls - * <code>exec(cmd, env, null)</code>. A security check is performed, - * <code>checkExec</code>. - * - * @param cmd the command to call - * @param env the environment to use, in the format name=value - * @return the Process object - * @throws SecurityException if permission is denied - * @throws IOException if an I/O error occurs - * @throws NullPointerException if cmd is null, or cmd or env has null - * entries - * @throws IndexOutOfBoundsException if cmd is length 0 - */ - public Process exec(String[] cmd, String[] env) throws IOException - { - return exec(cmd, env, null); - } - - /** - * Create a new subprocess with the specified command line, already - * tokenized, and the specified environment and working directory. If the - * environment is null, the process inherits the environment of this - * process. If the directory is null, the process uses the current working - * directory. A security check is performed, <code>checkExec</code>. - * - * @param cmd the command to call - * @param env the environment to use, in the format name=value - * @param dir the working directory to use - * @return the Process object - * @throws SecurityException if permission is denied - * @throws IOException if an I/O error occurs - * @throws NullPointerException if cmd is null, or cmd or env has null - * entries - * @throws IndexOutOfBoundsException if cmd is length 0 - * @since 1.3 - */ - public Process exec(String[] cmd, String[] env, File dir) - throws IOException - { - SecurityManager sm = SecurityManager.current; // Be thread-safe! - if (sm != null) - sm.checkExec(cmd[0]); - return execInternal(cmd, env, dir); - } - - /** - * Returns the number of available processors currently available to the - * virtual machine. This number may change over time; so a multi-processor - * program want to poll this to determine maximal resource usage. - * - * @return the number of processors available, at least 1 - */ - public native int availableProcessors(); - - /** - * Find out how much memory is still free for allocating Objects on the heap. - * - * @return the number of bytes of free memory for more Objects - */ - public native long freeMemory(); - - /** - * Find out how much memory total is available on the heap for allocating - * Objects. - * - * @return the total number of bytes of memory for Objects - */ - public native long totalMemory(); - - /** - * Returns the maximum amount of memory the virtual machine can attempt to - * use. This may be <code>Long.MAX_VALUE</code> if there is no inherent - * limit (or if you really do have a 8 exabyte memory!). - * - * @return the maximum number of bytes the virtual machine will attempt - * to allocate - */ - public native long maxMemory(); - - /** - * Run the garbage collector. This method is more of a suggestion than - * anything. All this method guarantees is that the garbage collector will - * have "done its best" by the time it returns. Notice that garbage - * collection takes place even without calling this method. - */ - public native void gc(); - - /** - * Run finalization on all Objects that are waiting to be finalized. Again, - * a suggestion, though a stronger one than {@link #gc()}. This calls the - * <code>finalize</code> method of all objects waiting to be collected. - * - * @see #finalize() - */ - public native void runFinalization(); - - /** - * Tell the VM to trace every bytecode instruction that executes (print out - * a trace of it). No guarantees are made as to where it will be printed, - * and the VM is allowed to ignore this request. - * - * @param on whether to turn instruction tracing on - */ - public native void traceInstructions(boolean on); - - /** - * Tell the VM to trace every method call that executes (print out a trace - * of it). No guarantees are made as to where it will be printed, and the - * VM is allowed to ignore this request. - * - * @param on whether to turn method tracing on - */ - public native void traceMethodCalls(boolean on); - - /** - * Load a native library using the system-dependent filename. This is similar - * to loadLibrary, except the only name mangling done is inserting "_g" - * before the final ".so" if the VM was invoked by the name "java_g". There - * may be a security check, of <code>checkLink</code>. - * - * @param filename the file to load - * @throws SecurityException if permission is denied - * @throws UnsatisfiedLinkError if the library is not found - */ - public void load(String filename) - { - SecurityManager sm = SecurityManager.current; // Be thread-safe! - if (sm != null) - sm.checkLink(filename); - _load(filename, false); - } - - /** - * Load a native library using a system-independent "short name" for the - * library. It will be transformed to a correct filename in a - * system-dependent manner (for example, in Windows, "mylib" will be turned - * into "mylib.dll"). This is done as follows: if the context that called - * load has a ClassLoader cl, then <code>cl.findLibrary(libpath)</code> is - * used to convert the name. If that result was null, or there was no class - * loader, this searches each directory of the system property - * <code>java.library.path</code> for a file named - * <code>System.mapLibraryName(libname)</code>. There may be a security - * check, of <code>checkLink</code>. - * - * @param libname the library to load - * - * @throws SecurityException if permission is denied - * @throws UnsatisfiedLinkError if the library is not found - * - * @see System#mapLibraryName(String) - * @see ClassLoader#findLibrary(String) - */ - public void loadLibrary(String libname) - { - // This is different from the Classpath implementation, but I - // believe it is more correct. - SecurityManager sm = SecurityManager.current; // Be thread-safe! - if (sm != null) - sm.checkLink(libname); - _load(libname, true); - } - - /** - * Return a localized version of this InputStream, meaning all characters - * are localized before they come out the other end. - * - * @param in the stream to localize - * @return the localized stream - * @deprecated <code>InputStreamReader</code> is the preferred way to read - * local encodings - */ - public InputStream getLocalizedInputStream(InputStream in) - { - return in; - } - - /** - * Return a localized version of this OutputStream, meaning all characters - * are localized before they are sent to the other end. - * - * @param out the stream to localize - * @return the localized stream - * @deprecated <code>OutputStreamWriter</code> is the preferred way to write - * local encodings - */ - public OutputStream getLocalizedOutputStream(OutputStream out) - { - return out; - } - - /** - * Native method that actually shuts down the virtual machine. - * - * @param status the status to end the process with - */ - native void exitInternal(int status); - - /** - * Load a file. If it has already been loaded, do nothing. The name has - * already been mapped to a true filename. - * - * @param filename the file to load - * @param do_search True if we should search the load path for the file - */ - native void _load(String filename, boolean do_search); - - /** - *This is a helper function for the ClassLoader which can load - * compiled libraries. Returns true if library (which is just the - * base name -- path searching is done by this function) was loaded, - * false otherwise. - */ - native boolean loadLibraryInternal(String libname); - - /** - * A helper for Runtime static initializer which does some internal native - * initialization. - */ - private static native void init (); - - /** - * Run finalizers when exiting. - */ - private native void runFinalizationForExit(); - - /** - * Map a system-independent "short name" to the full file name, and append - * it to the path. - * XXX This method is being replaced by System.mapLibraryName. - * - * @param pathname the path - * @param libname the short version of the library name - * @return the full filename - */ - static native String nativeGetLibname(String pathname, String libname); - - /** - * Execute a process. The command line has already been tokenized, and - * the environment should contain name=value mappings. If directory is null, - * use the current working directory; otherwise start the process in that - * directory. - * - * @param cmd the non-null command tokens - * @param env the non-null environment setup - * @param dir the directory to use, may be null - * @return the newly created process - * @throws NullPointerException if cmd or env have null elements - * @throws IOException if the exec fails - */ - native Process execInternal(String[] cmd, String[] env, File dir) - throws IOException; -} // class Runtime |