/*

 * Copyright (c) 2009, 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.util.logging;

import java.lang.reflect.Field;

import java.security.AccessController;

import java.security.PrivilegedAction;

import java.util.Date;

/**

 * Internal API to support JRE implementation to detect if the java.util.logging

 * support is available but with no dependency on the java.util.logging

 * classes.  This LoggingSupport class provides several static methods to

 * access the java.util.logging functionality that requires the caller

 * to ensure that the logging support is {@linkplain #isAvailable available}

 * before invoking it.

 *

 * @see sun.util.logging.PlatformLogger if you want to log messages even

 * if the logging support is not available

 */

public class LoggingSupport {

    private LoggingSupport() { }

    private static final LoggingProxy proxy =

        AccessController.doPrivileged(new PrivilegedAction<LoggingProxy>() {

            public LoggingProxy run() {

                try {

                    // create a LoggingProxyImpl instance when

                    // java.util.logging classes exist

                    Class<?> c = Class.forName("java.util.logging.LoggingProxyImpl", true, null);

                    Field f = c.getDeclaredField("INSTANCE");

                    f.setAccessible(true);

                    return (LoggingProxy) f.get(null);

                } catch (ClassNotFoundException cnf) {

                    return null;

                } catch (NoSuchFieldException e) {

                    throw new AssertionError(e);

                } catch (IllegalAccessException e) {

                    throw new AssertionError(e);

                }

            }});

    /**

     * Returns true if java.util.logging support is available.

     */

    public static boolean isAvailable() {

        return proxy != null;

    }

    private static void ensureAvailable() {

        if (proxy == null)

            throw new AssertionError("Should not here");

    }

    public static java.util.List<String> getLoggerNames() {

        ensureAvailable();

        return proxy.getLoggerNames();

    }

    public static String getLoggerLevel(String loggerName) {

        ensureAvailable();

        return proxy.getLoggerLevel(loggerName);

    }

    public static void setLoggerLevel(String loggerName, String levelName) {

        ensureAvailable();

        proxy.setLoggerLevel(loggerName, levelName);

    }

    public static String getParentLoggerName(String loggerName) {

        ensureAvailable();

        return proxy.getParentLoggerName(loggerName);

    }

    public static Object getLogger(String name) {

        ensureAvailable();

        return proxy.getLogger(name);

    }

    public static Object getLevel(Object logger) {

        ensureAvailable();

        return proxy.getLevel(logger);

    }

    public static void setLevel(Object logger, Object newLevel) {

        ensureAvailable();

        proxy.setLevel(logger, newLevel);

    }

    public static boolean isLoggable(Object logger, Object level) {

        ensureAvailable();

        return proxy.isLoggable(logger,level);

    }

    public static void log(Object logger, Object level, String msg) {

        ensureAvailable();

        proxy.log(logger, level, msg);

    }

    public static void log(Object logger, Object level, String msg, Throwable t) {

        ensureAvailable();

        proxy.log(logger, level, msg, t);

    }

    public static void log(Object logger, Object level, String msg, Object... params) {

        ensureAvailable();

        proxy.log(logger, level, msg, params);

    }

    public static Object parseLevel(String levelName) {

        ensureAvailable();

        return proxy.parseLevel(levelName);

    }

    public static String getLevelName(Object level) {

        ensureAvailable();

        return proxy.getLevelName(level);

    }

    private static final String DEFAULT_FORMAT =

        "%1$tb %1$td, %1$tY %1$tl:%1$tM:%1$tS %1$Tp %2$s%n%4$s: %5$s%6$s%n";

    private static final String FORMAT_PROP_KEY = "java.util.logging.SimpleFormatter.format";

    public static String getSimpleFormat() {

        return getSimpleFormat(true);

    }

    // useProxy if true will cause initialization of

    // java.util.logging and read its configuration

    static String getSimpleFormat(boolean useProxy) {

        String format =

            AccessController.doPrivileged(

                new PrivilegedAction<String>() {

                    public String run() {

                        return System.getProperty(FORMAT_PROP_KEY);

                    }

                });

        if (useProxy && proxy != null && format == null) {

            format = proxy.getProperty(FORMAT_PROP_KEY);

        }

        if (format != null) {

            try {

                // validate the user-defined format string

                String.format(format, new Date(), "", "", "", "", "");

            } catch (IllegalArgumentException e) {

                // illegal syntax; fall back to the default format

                format = DEFAULT_FORMAT;

            }

        } else {

            format = DEFAULT_FORMAT;

        }

        return format;

    }

}