001/**
002 * Logback: the reliable, generic, fast and flexible logging framework.
003 * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
004 *
005 * This program and the accompanying materials are dual-licensed under
006 * either the terms of the Eclipse Public License v1.0 as published by
007 * the Eclipse Foundation
008 *
009 *   or (per the licensee's choosing)
010 *
011 * under the terms of the GNU Lesser General Public License version 2.1
012 * as published by the Free Software Foundation.
013 */
014package ch.qos.logback.core.util;
015
016import ch.qos.logback.core.Context;
017import ch.qos.logback.core.CoreConstants;
018import ch.qos.logback.core.spi.ContextAware;
019import ch.qos.logback.core.spi.LifeCycle;
020import ch.qos.logback.core.status.OnConsoleStatusListener;
021import ch.qos.logback.core.status.StatusListener;
022
023public class StatusListenerConfigHelper {
024
025    public static void installIfAsked(Context context) {
026        String slClass = OptionHelper.getSystemProperty(CoreConstants.STATUS_LISTENER_CLASS_KEY);
027        if (!OptionHelper.isNullOrEmpty(slClass)) {
028            addStatusListener(context, slClass);
029        }
030    }
031
032    private static void addStatusListener(Context context, String listenerClassName) {
033        StatusListener listener = null;
034        if (CoreConstants.SYSOUT.equalsIgnoreCase(listenerClassName)) {
035            listener = new OnConsoleStatusListener();
036        } else {
037            listener = createListenerPerClassName(context, listenerClassName);
038        }
039        initAndAddListener(context, listener);
040    }
041
042    private static void initAndAddListener(Context context, StatusListener listener) {
043        if (listener != null) {
044            if (listener instanceof ContextAware) // LOGBACK-767
045                ((ContextAware) listener).setContext(context);
046
047            boolean effectivelyAdded = context.getStatusManager().add(listener);
048            if (effectivelyAdded && (listener instanceof LifeCycle)) {
049                ((LifeCycle) listener).start(); // LOGBACK-767
050            }
051        }
052    }
053
054    private static StatusListener createListenerPerClassName(Context context, String listenerClass) {
055        try {
056            return (StatusListener) OptionHelper.instantiateByClassName(listenerClass, StatusListener.class, context);
057        } catch (Exception e) {
058            // printing on the console is the best we can do
059            e.printStackTrace();
060            return null;
061        }
062    }
063
064    /**
065     * This utility method adds a new OnConsoleStatusListener to the context passed
066     * as parameter.
067     *
068     * @param context
069     * @since 1.0.1
070     */
071    static public void addOnConsoleListenerInstance(Context context, OnConsoleStatusListener onConsoleStatusListener) {
072        onConsoleStatusListener.setContext(context);
073        boolean effectivelyAdded = context.getStatusManager().add(onConsoleStatusListener);
074        if (effectivelyAdded) {
075            onConsoleStatusListener.start();
076        }
077    }
078}