Scala example source code file (Log.java)

This example Scala source code file (Log.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

debug, debug, error, info, io, level, object, object, printstream, printstream, stringconcatenation, suppresswarnings, throwable, trace, trace

The Scala Log.java source code

/*
 * 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 scala.tools.jline.internal;

import java.io.PrintStream;

/**
 * Internal logger.
 *
 * @author <a href="mailto:jason@planet57.com">Jason Dillon
 * @since 2.0
 */
public final class Log
{
    ///CLOVER:OFF

    public static enum Level
    {
        TRACE,
        DEBUG,
        INFO,
        WARN,
        ERROR
    }

    @SuppressWarnings({"StringConcatenation"})
    public static final boolean DEBUG = Boolean.getBoolean(Log.class.getName() + ".debug");

    @SuppressWarnings({"StringConcatenation"})
    public static final boolean TRACE = Boolean.getBoolean(Log.class.getName() + ".trace");

    private static PrintStream output = System.err;

    public static PrintStream getOutput() {
        return output;
    }

    public static void setOutput(final PrintStream out) {
        assert out != null;
        output = out;
    }

    private static void print(final Object message) {
        if (message instanceof Throwable) {
            ((Throwable) message).printStackTrace();
        }
        else if (message.getClass().isArray()) {
            Object[] array = (Object[]) message;

            for (int i = 0; i < array.length; i++) {
                output.print(array[i]);
                if (i + 1 < array.length) {
                    output.print(",");
                }
            }
        }
        else {
            output.print(message);
        }
    }

    private static void log(final Level level, final Object[] messages) {
        //noinspection SynchronizeOnNonFinalField
        synchronized (output) {
            output.format("[%s] ", level);

            for (Object message : messages) {
                print(message);
            }

            output.println();
            output.flush();
        }
    }

    public static void trace(final Object... messages) {
        if (TRACE) {
            log(Level.TRACE, messages);
        }
    }

    public static void debug(final Object... messages) {
        if (TRACE || DEBUG) {
            log(Level.DEBUG, messages);
        }
    }

    public static void warn(final Object... messages) {
        log(Level.WARN, messages);
    }

    public static void error(final Object... messages) {
        log(Level.ERROR, messages);
    }
}