/*

 * Copyright (c) 1995, 2008, 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 java.lang;

/**

 * The {@code Compiler} class is provided to support Java-to-native-code

 * compilers and related services. By design, the {@code Compiler} class does

 * nothing; it serves as a placeholder for a JIT compiler implementation.

 *

 * <p> When the Java Virtual Machine first starts, it determines if the system

 * property {@code java.compiler} exists. (System properties are accessible

 * through {@link System#getProperty(String)} and {@link

 * System#getProperty(String, String)}.  If so, it is assumed to be the name of

 * a library (with a platform-dependent exact location and type); {@link

 * System#loadLibrary} is called to load that library. If this loading

 * succeeds, the function named {@code java_lang_Compiler_start()} in that

 * library is called.

 *

 * <p> If no compiler is available, these methods do nothing.

 *

 * @author  Frank Yellin

 * @since   JDK1.0

 */

public final class Compiler  {

    private Compiler() {}               // don't make instances

    private static native void initialize();

    private static native void registerNatives();

    static {

        registerNatives();

        java.security.AccessController.doPrivileged(

            new java.security.PrivilegedAction<Void>() {

                public Void run() {

                    boolean loaded = false;

                    String jit = System.getProperty("java.compiler");

                    if ((jit != null) && (!jit.equals("NONE")) &&

                        (!jit.equals("")))

                    {

                        try {

                            System.loadLibrary(jit);

                            initialize();

                            loaded = true;

                        } catch (UnsatisfiedLinkError e) {

                            System.err.println("Warning: JIT compiler \"" +

                              jit + "\" not found. Will use interpreter.");

                        }

                    }

                    String info = System.getProperty("java.vm.info");

                    if (loaded) {

                        System.setProperty("java.vm.info", info + ", " + jit);

                    } else {

                        System.setProperty("java.vm.info", info + ", nojit");

                    }

                    return null;

                }

            });

    }

    /**

     * Compiles the specified class.

     *

     * @param  clazz

     *         A class

     *

     * @return  {@code true} if the compilation succeeded; {@code false} if the

     *          compilation failed or no compiler is available

     *

     * @throws  NullPointerException

     *          If {@code clazz} is {@code null}

     */

    public static native boolean compileClass(Class<?> clazz);

    /**

     * Compiles all classes whose name matches the specified string.

     *

     * @param  string

     *         The name of the classes to compile

     *

     * @return  {@code true} if the compilation succeeded; {@code false} if the

     *          compilation failed or no compiler is available

     *

     * @throws  NullPointerException

     *          If {@code string} is {@code null}

     */

    public static native boolean compileClasses(String string);

    /**

     * Examines the argument type and its fields and perform some documented

     * operation.  No specific operations are required.

     *

     * @param  any

     *         An argument

     *

     * @return  A compiler-specific value, or {@code null} if no compiler is

     *          available

     *

     * @throws  NullPointerException

     *          If {@code any} is {@code null}

     */

    public static native Object command(Object any);

    /**

     * Cause the Compiler to resume operation.

     */

    public static native void enable();

    /**

     * Cause the Compiler to cease operation.

     */

    public static native void disable();

}