| /* VMRuntime.java -- VM interface to Runtime |
| Copyright (C) 2003 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 java.io.File; |
| import java.io.IOException; |
| |
| /** |
| * VMRuntime represents the interface to the Virtual Machine. |
| * |
| * @author Jeroen Frijters |
| */ |
| final class VMRuntime |
| { |
| /** |
| * No instance is ever created. |
| */ |
| private VMRuntime() |
| { |
| } |
| |
| /** |
| * 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 |
| */ |
| static 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 |
| */ |
| static 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 |
| */ |
| static 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 |
| */ |
| static 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. |
| */ |
| static 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() |
| */ |
| static native void runFinalization(); |
| |
| /** |
| * Run finalization on all finalizable Objects (even live ones). This |
| * should only be called immediately prior to VM termination. |
| * |
| * @see #finalize() |
| */ |
| static native void runFinalizationForExit(); |
| |
| /** |
| * 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 |
| */ |
| static 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 |
| */ |
| static native void traceMethodCalls(boolean on); |
| |
| /** |
| * Native method that actually sets the finalizer setting. |
| * |
| * @param value whether to run finalizers on exit |
| */ |
| static native void runFinalizersOnExit(boolean value); |
| |
| /** |
| * Native method that actually shuts down the virtual machine. |
| * |
| * @param status the status to end the process with |
| */ |
| static native void exit(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 loader class loader, or <code>null</code> for the boot loader |
| * @return 0 on failure, nonzero on success |
| */ |
| static native int nativeLoad(String filename, ClassLoader loader); |
| |
| /** |
| * Map a system-independent "short name" to the full file name. |
| * |
| * @param libname the short version of the library name |
| * @return the full filename |
| */ |
| static native String mapLibraryName(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. If env is null, then the new process should inherit |
| * the environment of this process. |
| * |
| * @param cmd the non-null command tokens |
| * @param env the 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 |
| */ |
| static Process exec(String[] cmd, String[] env, File dir) |
| throws IOException { |
| return VMProcess.exec(cmd, env, dir); |
| } |
| |
| /** |
| * This method is called by Runtime.addShutdownHook() when it is |
| * called for the first time. It enables the VM to lazily setup |
| * an exit handler, should it so desire. |
| */ |
| static void enableShutdownHooks() |
| { |
| } |
| } // class VMRuntime |