system.java

kaffe是一个java虚拟机的源代码。里面包含了一些java例程和标准的java包。

/*
 * Java core library component.
 *
 * Copyright (c) 1997, 1998
 *      Transvirtual Technologies, Inc.  All rights reserved.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file.
 */

package java.lang;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileDescriptor;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintStream;
import java.util.Properties;

public final class System {
	final public static InputStream in;
	final public static PrintStream out;
	final public static PrintStream err;
	private static Properties props;
	private static SecurityManager security;

// When trying to debug Java code that gets executed early on during
// JVM initialization, eg, before System.err is initialized, debugging
// println() statements don't work. In these cases, the following routines
// are very handy. Simply uncomment the following two lines to enable them.

/****
public static native void debug(String s);	// print s to stderr, then \n
public static native void debugE(Throwable t);	// print stack trace to stderr
****/

static {
	// XXX what are the constraints on the initialization order in here?

	props = initProperties(new Properties());
	// Load any system properties from the system.properties resource
	InputStream sin = ClassLoader.getSystemResourceAsStream("system.properties");
	if (sin != null) {
		try {
			props.load(sin);
		}
		catch (IOException e) {
		}
		finally {
			try {
				sin.close();
			}
			catch (IOException e) {
			}
		}
	}

	// Initialise the I/O
	if (props.getProperty("kaffe.embedded", "false").equals("false")) {

		in = new BufferedInputStream(new FileInputStream(FileDescriptor.in), 128);
		out = new PrintStream(new BufferedOutputStream(new FileOutputStream(FileDescriptor.out), 128), true);
		err = new PrintStream(new BufferedOutputStream(new FileOutputStream(FileDescriptor.err), 128), true);
	}
	else {
		in = new BufferedInputStream(new kaffe.io.StdInputStream(), 128);
		out = new PrintStream(new BufferedOutputStream(new kaffe.io.StdOutputStream(), 128), true);
		err = new PrintStream(new BufferedOutputStream(new kaffe.io.StdErrorStream(), 128), true);
	}

	// Initialize the system class loader
	try {
		Class.forName("kaffe.lang.SystemClassLoader");
	}
	catch (ClassNotFoundException _)
	{
		// Kaffe won't let exceptions be thrown this early in
		// the init process, anyway...
	}
}

private System() { }

native public static void arraycopy(Object src,
	int src_position, Object dst, int dst_position, int length);

private static void checkPropertyAccess() {
	SecurityManager sm = getSecurityManager();
	if (sm != null)
		sm.checkPropertiesAccess();
}

native public static long currentTimeMillis();

public static void exit (int status) {
	Runtime.getRuntime().exit(status);
}

public static void gc() {
	Runtime.getRuntime().gc();
}

public static Properties getProperties() {
	checkPropertyAccess();

	return props;
}

public static String getProperty(String key) {
	checkPropertyAccess();

	return props.getProperty(key);
}

public static String getProperty(String key, String def) {
	checkPropertyAccess();

	return props.getProperty(key, def);
}

public static SecurityManager getSecurityManager() {
	return security;
}

public static String getenv(String name) {
	throw new Error("System.getenv no longer supported");
}

native public static int identityHashCode(Object x);

native private static Properties initProperties(Properties props);

public static void load(String filename) {
	Runtime.getRuntime().load(filename,
	    Class.getStackClass(1).getClassLoader());
}

public static void loadLibrary(String libname) {
	Runtime.getRuntime().loadLibrary(libname,
	    Class.getStackClass(1).getClassLoader());
}

public static String mapLibraryName(String fn) {
	return NativeLibrary.getLibPrefix() + fn + NativeLibrary.getLibSuffix();
}

public static void runFinalization() {
	Runtime.getRuntime().runFinalization();
}

public static void runFinalizersOnExit(boolean value) {
	Runtime.getRuntime().runFinalizersOnExit(value);
}

public static void setErr(PrintStream err) {
	// XXX call security manager for RuntimePermission("SetIO")
	setErr0(err);
}

native private static void setErr0(PrintStream err);

public static void setIn(InputStream in) {
	// XXX call security manager for RuntimePermission("SetIO")
	setIn0(in);
}

native private static void setIn0(InputStream in);

public static void setOut(PrintStream out) {
	// XXX call security manager for RuntimePermission("SetIO")
	setOut0(out);
}

native private static void setOut0(PrintStream out);

public static String setProperty(String key, String value) {
	checkPropertyAccess();
	return (String)props.setProperty(key, value);
}

public static void setProperties(Properties prps) {
	checkPropertyAccess();
	if (prps == null) {
		props.clear();
		return;
	}
	props = prps;
}

public static void setSecurityManager(SecurityManager s) {
	if (security != null) {
		security.checkPermission(
			new RuntimePermission("setSecurityManager"));
	}
	security = s;
}
}