Logback: the reliable, generic, fast and flexible logging framework.
Copyright (C) 1999-2015, QOS.ch. All rights reserved.
This program and the accompanying materials are dual-licensed under
either the terms of the Eclipse Public License v1.0 as published by
the Eclipse Foundation
  or (per the licensee's choosing)
under the terms of the GNU Lesser General Public License version 2.1
as published by the Free Software Foundation.
/**
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
 *
 * This program and the accompanying materials are dual-licensed under
 * either the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation
 *
 *   or (per the licensee's choosing)
 *
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 */
package ch.qos.logback.core.util;

import ch.qos.logback.core.Context;
import ch.qos.logback.core.CoreConstants;
import ch.qos.logback.core.spi.ContextAware;
import ch.qos.logback.core.spi.LifeCycle;
import ch.qos.logback.core.status.OnConsoleStatusListener;
import ch.qos.logback.core.status.StatusListener;

public class StatusListenerConfigHelper {

    public static void installIfAsked(Context context) {
        String slClass = OptionHelper.getSystemProperty(CoreConstants.STATUS_LISTENER_CLASS_KEY);
        if (!OptionHelper.isEmpty(slClass)) {
            addStatusListener(context, slClass);
        }
    }

    private static void addStatusListener(Context context, String listenerClassName) {
        StatusListener listener = null;
        if (CoreConstants.SYSOUT.equalsIgnoreCase(listenerClassName)) {
            listener = new OnConsoleStatusListener();
        } else {
            listener = createListenerPerClassName(context, listenerClassName);
        }
        initAndAddListener(context, listener);
    }

    private static void initAndAddListener(Context context, StatusListener listener) {
        if (listener != null) {
            if (listener instanceof ContextAware) // LOGBACK-767
                ((ContextAware) listener).setContext(context);

            boolean effectivelyAdded = context.getStatusManager().add(listener);
            if (effectivelyAdded && (listener instanceof LifeCycle)) {
                ((LifeCycle) listener).start(); // LOGBACK-767
            }
        }
    }

    private static StatusListener createListenerPerClassName(Context context, String listenerClass) {
        try {
            return (StatusListener) OptionHelper.instantiateByClassName(listenerClass, StatusListener.class, context);
        } catch (Exception e) {
            // printing on the console is the best we can do
            e.printStackTrace();
            return null;
        }
    }

    
This utility method adds a new OnConsoleStatusListener to the context
passed as parameter.
Params:
context – 
Since:
1.0.1/**
       * This utility method adds a new OnConsoleStatusListener to the context
       * passed as parameter.
       *
       * @param context
       * @since 1.0.1
       */
    static public void addOnConsoleListenerInstance(Context context, OnConsoleStatusListener onConsoleStatusListener) {
        onConsoleStatusListener.setContext(context);
        boolean effectivelyAdded = context.getStatusManager().add(onConsoleStatusListener);
        if (effectivelyAdded) {
            onConsoleStatusListener.start();
        }
    }
}