hu.blackbelt.osgi.liquibase.logging.Slf4jLogService Maven / Gradle / Ivy

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package hu.blackbelt.osgi.liquibase.logging;

/*-
 * #%L
 * OSGi liquibase
 * %%
 * Copyright (C) 2018 - 2022 BlackBelt Technology
 * %%
 * Licensed 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.
 * #L%
 */

import liquibase.logging.Logger;
import liquibase.logging.core.AbstractLogService;
import org.slf4j.LoggerFactory;

import java.util.Properties;

/**
 * Liquibase {@link liquibase.logging.LogService} that creates an SLF4J-backed logger.
 */
public class Slf4jLogService extends AbstractLogService {

    private static final int DEFAULT_PRIORITY = 5;
    private static final String PRIORITY_PROPERTY_NAME = Slf4jLogService.class.getName() + ".priority";

    private int priority;

    /**
     * Default constructor is needed for ServiceLoader to work.
     *
     * @see liquibase.servicelocator.StandardServiceLocator
     */
    public Slf4jLogService() {
        this(System.getProperties());
    }

    /**
     * Constructor visible for testing.
     */
    Slf4jLogService(final Properties systemProps) {
        priority = DEFAULT_PRIORITY;
        String priorityPropertyValue = systemProps.getProperty(PRIORITY_PROPERTY_NAME);
        if (priorityPropertyValue != null && !priorityPropertyValue.isEmpty()) {
            try {
                priority = Integer.parseInt(priorityPropertyValue);
            } catch (NumberFormatException e) {
                // Do nothing
            }
        }
    }

    /**
     * Gets the logger priority for this logger. The priority is used by Liquibase to determine which LogService to use.
     * The LogService with the highest priority will be selected. This implementation's priority is set to 5. Remove loggers
     * with higher priority numbers if needed.
     *
     * @return The priority integer. Defaults to 5 if no override is given.
     */
    @Override
    public int getPriority() {
        return priority;
    }

    /**
     * Takes the given class argument and associates it with a SLF4J logger.
     *
     * @param clazz The class to create an SLF4J logger for
     */
    @Override
    public Logger getLog(Class clazz) {
        return new Slf4jLogger(LoggerFactory.getLogger(clazz), getFilter());
    }
}