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Diffstat (limited to 'libjava/classpath/vm/reference/java/lang/VMRuntime.java')
| -rw-r--r-- | libjava/classpath/vm/reference/java/lang/VMRuntime.java | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/libjava/classpath/vm/reference/java/lang/VMRuntime.java b/libjava/classpath/vm/reference/java/lang/VMRuntime.java new file mode 100644 index 000000000..0b58d5f44 --- /dev/null +++ b/libjava/classpath/vm/reference/java/lang/VMRuntime.java @@ -0,0 +1,192 @@ +/* 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 |