/*

 * Copyright (c) 1996, 2010, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.misc;

import static java.lang.Thread.State.*;

import java.util.Properties;

import java.util.HashMap;

import java.util.Map;

import java.util.Set;

public class VM {

    /* The following methods used to be native methods that instruct

     * the VM to selectively suspend certain threads in low-memory

     * situations. They are inherently dangerous and not implementable

     * on native threads. We removed them in JDK 1.2. The skeletons

     * remain so that existing applications that use these methods

     * will still work.

     */

    private static boolean suspended = false;

    /** @deprecated */

    @Deprecated

    public static boolean threadsSuspended() {

        return suspended;

    }

    public static boolean allowThreadSuspension(ThreadGroup g, boolean b) {

        return g.allowThreadSuspension(b);

    }

    /** @deprecated */

    @Deprecated

    public static boolean suspendThreads() {

        suspended = true;

        return true;

    }

    // Causes any suspended threadgroups to be resumed.

    /** @deprecated */

    @Deprecated

    public static void unsuspendThreads() {

        suspended = false;

    }

    // Causes threadgroups no longer marked suspendable to be resumed.

    /** @deprecated */

    @Deprecated

    public static void unsuspendSomeThreads() {

    }

    /* Deprecated fields and methods -- Memory advice not supported in 1.2 */

    /** @deprecated */

    @Deprecated

    public static final int STATE_GREEN = 1;

    /** @deprecated */

    @Deprecated

    public static final int STATE_YELLOW = 2;

    /** @deprecated */

    @Deprecated

    public static final int STATE_RED = 3;

    /** @deprecated */

    @Deprecated

    public static final int getState() {

        return STATE_GREEN;

    }

    /** @deprecated */

    @Deprecated

    public static void registerVMNotification(VMNotification n) { }

    /** @deprecated */

    @Deprecated

    public static void asChange(int as_old, int as_new) { }

    /** @deprecated */

    @Deprecated

    public static void asChange_otherthread(int as_old, int as_new) { }

    /*

     * Not supported in 1.2 because these will have to be exported as

     * JVM functions, and we are not sure we want do that. Leaving

     * here so it can be easily resurrected -- just remove the //

     * comments.

     */

    /**

     * Resume Java profiling.  All profiling data is added to any

     * earlier profiling, unless <code>resetJavaProfiler</code> is

     * called in between.  If profiling was not started from the

     * command line, <code>resumeJavaProfiler</code> will start it.

     * <p>

     *

     * NOTE: Profiling must be enabled from the command line for a

     * java.prof report to be automatically generated on exit; if not,

     * writeJavaProfilerReport must be invoked to write a report.

     *

     * @see     resetJavaProfiler

     * @see     writeJavaProfilerReport

     */

    // public native static void resumeJavaProfiler();

    /**

     * Suspend Java profiling.

     */

    // public native static void suspendJavaProfiler();

    /**

     * Initialize Java profiling.  Any accumulated profiling

     * information is discarded.

     */

    // public native static void resetJavaProfiler();

    /**

     * Write the current profiling contents to the file "java.prof".

     * If the file already exists, it will be overwritten.

     */

    // public native static void writeJavaProfilerReport();

    private static volatile boolean booted = false;

    // Invoked by by System.initializeSystemClass just before returning.

    // Subsystems that are invoked during initialization can check this

    // property in order to avoid doing things that should wait until the

    // application class loader has been set up.

    //

    public static void booted() {

        booted = true;

    }

    public static boolean isBooted() {

        return booted;

    }

    // A user-settable upper limit on the maximum amount of allocatable direct

    // buffer memory.  This value may be changed during VM initialization if

    // "java" is launched with "-XX:MaxDirectMemorySize=<size>".

    //

    // The initial value of this field is arbitrary; during JRE initialization

    // it will be reset to the value specified on the command line, if any,

    // otherwise to Runtime.getRuntime.maxDirectMemory().

    //

    private static long directMemory = 64 * 1024 * 1024;

    // Returns the maximum amount of allocatable direct buffer memory.

    // The directMemory variable is initialized during system initialization

    // in the saveAndRemoveProperties method.

    //

    public static long maxDirectMemory() {

        return directMemory;

    }

    // User-controllable flag that determines if direct buffers should be page

    // aligned. The "-XX:+PageAlignDirectMemory" option can be used to force

    // buffers, allocated by ByteBuffer.allocateDirect, to be page aligned.

    private static boolean pageAlignDirectMemory;

    // Returns {@code true} if the direct buffers should be page aligned. This

    // variable is initialized by saveAndRemoveProperties.

    public static boolean isDirectMemoryPageAligned() {

        return pageAlignDirectMemory;

    }

    // A user-settable boolean to determine whether ClassLoader.loadClass should

    // accept array syntax.  This value may be changed during VM initialization

    // via the system property "sun.lang.ClassLoader.allowArraySyntax".

    //

    // The default for 1.5 is "true", array syntax is allowed.  In 1.6, the

    // default will be "false".  The presence of this system property to

    // control array syntax allows applications the ability to preview this new

    // behaviour.

    //

    private static boolean defaultAllowArraySyntax = false;

    private static boolean allowArraySyntax = defaultAllowArraySyntax;

    // The allowArraySyntax boolean is initialized during system initialization

    // in the saveAndRemoveProperties method.

    //

    // It is initialized based on the value of the system property

    // "sun.lang.ClassLoader.allowArraySyntax".  If the system property is not

    // provided, the default for 1.5 is "true".  In 1.6, the default will be

    // "false".  If the system property is provided, then the value of

    // allowArraySyntax will be equal to "true" if Boolean.parseBoolean()

    // returns "true".   Otherwise, the field will be set to "false".

    //

    public static boolean allowArraySyntax() {

        return allowArraySyntax;

    }

    /**

     * Returns the system property of the specified key saved at

     * system initialization time.  This method should only be used

     * for the system properties that are not changed during runtime.

     * It accesses a private copy of the system properties so

     * that user's locking of the system properties object will not

     * cause the library to deadlock.

     *

     * Note that the saved system properties do not include

     * the ones set by sun.misc.Version.init().

     *

     */

    public static String getSavedProperty(String key) {

        if (savedProps.isEmpty())

            throw new IllegalStateException("Should be non-empty if initialized");

        return savedProps.getProperty(key);

    }

    private static final Properties savedProps = new Properties();

    // Save a private copy of the system properties and remove

    // the system properties that are not intended for public access.

    //

    // This method can only be invoked during system initialization.

    public static void saveAndRemoveProperties(Properties props) {

        if (booted)

            throw new IllegalStateException("System initialization has completed");

        savedProps.putAll(props);

        // Set the maximum amount of direct memory.  This value is controlled

        // by the vm option -XX:MaxDirectMemorySize=<size>.

        // The maximum amount of allocatable direct buffer memory (in bytes)

        // from the system property sun.nio.MaxDirectMemorySize set by the VM.

        // The system property will be removed.

        String s = (String)props.remove("sun.nio.MaxDirectMemorySize");

        if (s != null) {

            if (s.equals("-1")) {

                // -XX:MaxDirectMemorySize not given, take default

                directMemory = Runtime.getRuntime().maxMemory();

            } else {

                long l = Long.parseLong(s);

                if (l > -1)

                    directMemory = l;

            }

        }

        // Check if direct buffers should be page aligned

        s = (String)props.remove("sun.nio.PageAlignDirectMemory");

        if ("true".equals(s))

            pageAlignDirectMemory = true;

        // Set a boolean to determine whether ClassLoader.loadClass accepts

        // array syntax.  This value is controlled by the system property

        // "sun.lang.ClassLoader.allowArraySyntax".

        s = props.getProperty("sun.lang.ClassLoader.allowArraySyntax");

        allowArraySyntax = (s == null

                               ? defaultAllowArraySyntax

                               : Boolean.parseBoolean(s));

        // Remove other private system properties

        // used by java.lang.Integer.IntegerCache

        props.remove("java.lang.Integer.IntegerCache.high");

        // used by java.util.zip.ZipFile

        props.remove("sun.zip.disableMemoryMapping");

    }

    // Initialize any miscellenous operating system settings that need to be

    // set for the class libraries.

    //

    public static void initializeOSEnvironment() {

        if (!booted) {

            OSEnvironment.initialize();

        }

    }

    /* Current count of objects pending for finalization */

    private static volatile int finalRefCount = 0;

    /* Peak count of objects pending for finalization */

    private static volatile int peakFinalRefCount = 0;

    /*

     * Gets the number of objects pending for finalization.

     *

     * @return the number of objects pending for finalization.

     */

    public static int getFinalRefCount() {

        return finalRefCount;

    }

    /*

     * Gets the peak number of objects pending for finalization.

     *

     * @return the peak number of objects pending for finalization.

     */

    public static int getPeakFinalRefCount() {

        return peakFinalRefCount;

    }

    /*

     * Add <tt>n</tt> to the objects pending for finalization count.

     *

     * @param n an integer value to be added to the objects pending

     * for finalization count

     */

    public static void addFinalRefCount(int n) {

        // The caller must hold lock to synchronize the update.

        finalRefCount += n;

        if (finalRefCount > peakFinalRefCount) {

            peakFinalRefCount = finalRefCount;

        }

    }

    /**

     * Returns Thread.State for the given threadStatus

     */

    public static Thread.State toThreadState(int threadStatus) {

        if ((threadStatus & JVMTI_THREAD_STATE_RUNNABLE) != 0) {

            return RUNNABLE;

        } else if ((threadStatus & JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER) != 0) {

            return BLOCKED;

        } else if ((threadStatus & JVMTI_THREAD_STATE_WAITING_INDEFINITELY) != 0) {

            return WAITING;

        } else if ((threadStatus & JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT) != 0) {

            return TIMED_WAITING;

        } else if ((threadStatus & JVMTI_THREAD_STATE_TERMINATED) != 0) {

            return TERMINATED;

        } else if ((threadStatus & JVMTI_THREAD_STATE_ALIVE) == 0) {

            return NEW;

        } else {

            return RUNNABLE;

        }

    }

    /* The threadStatus field is set by the VM at state transition

     * in the hotspot implementation. Its value is set according to

     * the JVM TI specification GetThreadState function.

     */

    private final static int JVMTI_THREAD_STATE_ALIVE = 0x0001;

    private final static int JVMTI_THREAD_STATE_TERMINATED = 0x0002;

    private final static int JVMTI_THREAD_STATE_RUNNABLE = 0x0004;

    private final static int JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER = 0x0400;

    private final static int JVMTI_THREAD_STATE_WAITING_INDEFINITELY = 0x0010;

    private final static int JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT = 0x0020;

    static {

        initialize();

    }

    private native static void initialize();

}