src/jdk.jfr/share/classes/jdk/jfr/internal/Logger.java

/*
 * Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package jdk.jfr.internal;

import java.util.function.Supplier;

/**
 * JFR logger
 *
 */

public final class Logger {

    private final static int MAX_SIZE = 10000;
    static {
        // This will try to initialize the JVM logging system
        JVMSupport.tryToInitializeJVM();
    }


    public static void log(LogTag logTag, LogLevel logLevel, String message) {
        if (shouldLog(logTag, logLevel)) {
            logInternal(logTag, logLevel, message);
        }
    }

    public static void log(LogTag logTag, LogLevel logLevel, Supplier<String> messageSupplier) {
        if (shouldLog(logTag, logLevel)) {
            logInternal(logTag, logLevel, messageSupplier.get());
        }
    }

    private static void logInternal(LogTag logTag, LogLevel logLevel, String message) {
        if (message == null || message.length() < MAX_SIZE) {
            JVM.log(logTag.id, logLevel.level, message);
        } else {
            JVM.log(logTag.id, logLevel.level, message.substring(0, MAX_SIZE));
        }
    }

    public static boolean shouldLog(LogTag tag, LogLevel level) {
        return level.level >= tag.tagSetLevel;
    }
}