PoiLogManager.java

/* ====================================================================
   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.
==================================================================== */

package org.apache.poi.logging;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.poi.util.ExceptionUtil;
import org.apache.poi.util.SuppressForbidden;

/**
 * This class is used to get a log4j logger for the XmlBeans project.
 * <p>Internal use only.</p>
 * <p>Fails over to a No-Op logger if there are problems creating log4j logger.</p>
 *
 * @since 5.4.0
 */
public final class PoiLogManager {

    // Sleep time in milliseconds (10 minutes)
    private static final long SLEEP_TIME = 10 * 60 * 1000;
    private static long LAST_TIME = 0;

    private PoiLogManager() {
    }

    @SuppressForbidden("printStackTrace")
    public static Logger getLogger(Class<?> clz) {
        try {
            final Logger logger = LogManager.getLogger(clz);
            if (logger == null) {
                if (shouldLog()) {
                    System.err.println("[PoiLogManager] Log4J returned null logger. Falling back to No-Op logger.");
                }
                return NoOpLogger.INSTANCE;
            }
            return logger;
        } catch (Throwable t) {
            if (!ExceptionUtil.isFatal(t)) {
                if (shouldLog()) {
                    System.err.println("[PoiLogManager] Issue loading Log4J. Falling back to No-Op logger.");
                    t.printStackTrace();
                }
            }
            return NoOpLogger.INSTANCE;
        }
    }

    @SuppressForbidden("printStackTrace")
    public static Logger getLogger(String name) {
        try {
            final Logger logger = LogManager.getLogger(name);
            if (logger == null) {
                if (shouldLog()) {
                    System.err.println("[PoiLogManager] Log4J returned null logger. Falling back to No-Op logger.");
                }
                return NoOpLogger.INSTANCE;
            }
            return logger;
        } catch (Throwable t) {
            if (!ExceptionUtil.isFatal(t)) {
                if (shouldLog()) {
                    System.err.println("[PoiLogManager] Issue loading Log4J. Falling back to No-Op logger.");
                    t.printStackTrace();
                }
            }
            return NoOpLogger.INSTANCE;
        }
    }

    private static synchronized boolean shouldLog() {
        final long time = System.currentTimeMillis();
        if (time > LAST_TIME + SLEEP_TIME) {
            LAST_TIME = time;
            return true;
        }
        return false;
    }

}