com/foo/config-qt.cpp

This file is an example of how to use the Qt event loop to monitor the Log4cxx configuration file.

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include "config-qt.h"
#include <log4cxx/basicconfigurator.h>
#include <log4cxx/logmanager.h>
#include <log4cxx-qt/configuration.h>
#include <log4cxx-qt/messagehandler.h>
#include <QCoreApplication>
#include <QFileInfo>
#include <QDir>
 
namespace com { namespace foo {
 
using namespace log4cxx;
 
// Provide the name of the configuration file to Log4cxx.
// Reload the configuration on a QFileSystemWatcher::fileChanged event.
void ConfigureLogging() {
    static struct log4cxx_initializer {
        log4cxx_initializer() {
            qInstallMessageHandler(qt::messageHandler);
        }
        ~log4cxx_initializer() {
            LogManager::shutdown();
        }
    } initialiser;
 
    QFileInfo app{QCoreApplication::applicationFilePath()};
    QString basename{app.baseName()};
    QVector<QString> paths =
        { QString(".")
        , app.absoluteDir().absolutePath()
        };
    QVector<QString> names =
        { QString(basename + ".xml")
        , QString(basename + ".properties")
        , QString("MyApp.properties")
        , QString("log4cxx.xml")
        , QString("log4cxx.properties")
    };
    auto status       = spi::ConfigurationStatus::NotConfigured;
    auto selectedPath = QString();
    std::tie(status, selectedPath) = qt::Configuration::configureFromFileAndWatch(paths, names);
    if (status == spi::ConfigurationStatus::NotConfigured)
        BasicConfigurator::configure(); // Send events to the console
}
 
// Retrieve the \c name logger pointer.
auto getLogger(const QString& name) -> LoggerPtr {
    return name.isEmpty()
        ? LogManager::getRootLogger()
        : LogManager::getLogger(name.toStdString());
}
 
// Retrieve the \c name logger pointer.
auto getLogger(const char* name) -> LoggerPtr {
    return name
        ? LogManager::getLogger(name)
        : LogManager::getRootLogger();
}
 
} } // namespace com::foo