src/main/java/com/sleepycat/je/utilint/FileRedirectHandler.java

/*-
 * Copyright (C) 2002, 2018, Oracle and/or its affiliates. All rights reserved.
 *
 * This file was distributed by Oracle as part of a version of Oracle Berkeley
 * DB Java Edition made available at:
 *
 * http://www.oracle.com/technetwork/database/database-technologies/berkeleydb/downloads/index.html
 *
 * Please see the LICENSE file included in the top-level directory of the
 * appropriate version of Oracle Berkeley DB Java Edition for a copy of the
 * license and additional information.
 */

package com.sleepycat.je.utilint;

import java.util.logging.Handler;
import java.util.logging.LogRecord;

import com.sleepycat.je.dbi.EnvironmentImpl;

/**
 * Redirects logging messages to the the owning environment's file handler, so
 * that messages can be prefixed with an environment name and sent to the
 * correct logging file.
 *
 * This class must not extend FileHandler itself, since FileHandlers open their
 * target log files at construction time, and this FileHandler is meant to be
 * stateless.
 */
public class FileRedirectHandler extends Handler {

    public FileRedirectHandler() {
        /* No need to call super, this handler is not truly publishing. */
    }

    @Override
    public void publish(LogRecord record) {
        EnvironmentImpl envImpl =
            LoggerUtils.envMap.get(Thread.currentThread());

        /*
         * Prefer to lose logging output, rather than risk a
         * NullPointerException if the caller forgets to set and release the
         * environmentImpl.
         */
        if (envImpl == null) {
            return;
        }

        /*
         * The FileHandler is not always created for an environment, because
         * creating a FileHandler automatically creates a logging file, and
         * we avoid doing that for read only environments. Because of that,
         * there may legitimately be no environment file handler.
         */
        if (envImpl.getFileHandler() == null) {
            return;
        }

        envImpl.getFileHandler().publish(record);
    }

    @Override
    public void close()
        throws SecurityException {

        /*
         * Nothing to do. The redirect target file handler is closed by
         * the environment.
         */
    }

    @Override
    public void flush() {

        /*
         * Nothing to do. If we want to flush this logger explicitly, flush
         * the underlying envImpl's handler.
         */
    }
}