Copyright (c) 2004-2011 QOS.ch
All rights reserved.
Permission is hereby granted, free  of charge, to any person obtaining
a  copy  of this  software  and  associated  documentation files  (the
"Software"), to  deal in  the Software without  restriction, including
without limitation  the rights to  use, copy, modify,  merge, publish,
distribute,  sublicense, and/or sell  copies of  the Software,  and to
permit persons to whom the Software  is furnished to do so, subject to
the following conditions:
The  above  copyright  notice  and  this permission  notice  shall  be
included in all copies or substantial portions of the Software.
THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
/**
 * Copyright (c) 2004-2011 QOS.ch
 * All rights reserved.
 *
 * Permission is hereby granted, free  of charge, to any person obtaining
 * a  copy  of this  software  and  associated  documentation files  (the
 * "Software"), to  deal in  the Software without  restriction, including
 * without limitation  the rights to  use, copy, modify,  merge, publish,
 * distribute,  sublicense, and/or sell  copies of  the Software,  and to
 * permit persons to whom the Software  is furnished to do so, subject to
 * the following conditions:
 *
 * The  above  copyright  notice  and  this permission  notice  shall  be
 * included in all copies or substantial portions of the Software.
 *
 * THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
 * EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
 * MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */
package org.slf4j.helpers;

An internal utility class.
Author:
Alexander Dorokhine, Ceki Gülcü/**
 * An internal utility class.
 *
 * @author Alexander Dorokhine
 * @author Ceki Gülcü
 */
public final class Util {

	
    private Util() {
    }

    public static String safeGetSystemProperty(String key) {
        if (key == null)
            throw new IllegalArgumentException("null input");

        String result = null;
        try {
            result = System.getProperty(key);
        } catch (java.lang.SecurityException sm) {
            ; // ignore
        }
        return result;
    }

    public static boolean safeGetBooleanSystemProperty(String key) {
        String value = safeGetSystemProperty(key);
        if (value == null)
            return false;
        else
            return value.equalsIgnoreCase("true");
    }

    
In order to call SecurityManager.getClassContext(), which is a protected method, we add this wrapper which allows the method to be visible inside this package. /**
     * In order to call {@link SecurityManager#getClassContext()}, which is a
     * protected method, we add this wrapper which allows the method to be visible
     * inside this package.
     */
    private static final class ClassContextSecurityManager extends SecurityManager {
        protected Class<?>[] getClassContext() {
            return super.getClassContext();
        }
    }

    private static ClassContextSecurityManager SECURITY_MANAGER;
    private static boolean SECURITY_MANAGER_CREATION_ALREADY_ATTEMPTED = false;

    private static ClassContextSecurityManager getSecurityManager() {
        if (SECURITY_MANAGER != null)
            return SECURITY_MANAGER;
        else if (SECURITY_MANAGER_CREATION_ALREADY_ATTEMPTED)
            return null;
        else {
            SECURITY_MANAGER = safeCreateSecurityManager();
            SECURITY_MANAGER_CREATION_ALREADY_ATTEMPTED = true;
            return SECURITY_MANAGER;
        }
    }

    private static ClassContextSecurityManager safeCreateSecurityManager() {
        try {
            return new ClassContextSecurityManager();
        } catch (java.lang.SecurityException sm) {
            return null;
        }
    }

    
Returns the name of the class which called the invoking method.
Returns:
the name of the class which called the invoking method./**
     * Returns the name of the class which called the invoking method.
     *
     * @return the name of the class which called the invoking method.
     */
    public static Class<?> getCallingClass() {
        ClassContextSecurityManager securityManager = getSecurityManager();
        if (securityManager == null)
            return null;
        Class<?>[] trace = securityManager.getClassContext();
        String thisClassName = Util.class.getName();

        // Advance until Util is found
        int i;
        for (i = 0; i < trace.length; i++) {
            if (thisClassName.equals(trace[i].getName()))
                break;
        }

        // trace[i] = Util; trace[i+1] = caller; trace[i+2] = caller's caller
        if (i >= trace.length || i + 2 >= trace.length) {
            throw new IllegalStateException("Failed to find org.slf4j.helpers.Util or its caller in the stack; " + "this should not happen");
        }

        return trace[i + 2];
    }

    static final public void report(String msg, Throwable t) {
        System.err.println(msg);
        System.err.println("Reported exception:");
        t.printStackTrace();
    }

    static final public void report(String msg) {
        System.err.println("SLF4J: " + msg);
    }
    
	

}