org.apache.juli.logging.ch.qos.logback.core.ConsoleAppender Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of tomcat10-slf4j-logback Show documentation
Tomcat10 Slf4j Logback Integration
There is a newer version: 10.1.23
Show newest version
/**
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
 *
 * This program and the accompanying materials are dual-licensed under
 * either the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation
 *
 *   or (per the licensee's choosing)
 *
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 */
package org.apache.juli.logging.ch.qos.logback.core;

import java.io.OutputStream;
import java.io.PrintStream;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Arrays;
import java.util.NoSuchElementException;
import java.util.Optional;

import org.apache.juli.logging.ch.qos.logback.core.joran.spi.ConsoleTarget;
import org.apache.juli.logging.ch.qos.logback.core.status.Status;
import org.apache.juli.logging.ch.qos.logback.core.status.WarnStatus;
import org.apache.juli.logging.ch.qos.logback.core.util.Loader;

/**
 * ConsoleAppender appends log events to System.out or
 * System.err using a layout specified by the user. The default
 * target is System.out.
 * 
 *  
 * 
 * For more information about this appender, please refer to the online manual
 * at http://logback.qos.ch/manual/appenders.html#ConsoleAppender
 *
 * @author Ceki Gülcü
 * @author Tom SH Liu
 * @author Ruediger Dohna
 */

public class ConsoleAppender extends OutputStreamAppender {

    protected ConsoleTarget target = ConsoleTarget.SystemOut;
    protected boolean withJansi = false;

    private final static String AnsiConsole_CLASS_NAME = "org.fusesource.jansi.AnsiConsole";
    private final static String JANSI2_OUT_METHOD_NAME = "out";
    private final static String JANSI2_ERR_METHOD_NAME = "err";
    private final static String wrapSystemOut_METHOD_NAME = "wrapSystemOut";
    private final static String wrapSystemErr_METHOD_NAME = "wrapSystemErr";
    private final static Class[] ARGUMENT_TYPES = { PrintStream.class };

    /**
     * Sets the value of the Target option. Recognized values are
     * "System.out" and "System.err". Any other value will be ignored.
     */
    public void setTarget(String value) {
        ConsoleTarget t = ConsoleTarget.findByName(value.trim());
        if (t == null) {
            targetWarn(value);
        } else {
            target = t;
        }
    }

    /**
     * Returns the current value of the target property. The default value of
     * the option is "System.out".
     * 
     * See also {@link #setTarget}.
     */
    public String getTarget() {
        return target.getName();
    }

    private void targetWarn(String val) {
        Status status = new WarnStatus("[" + val + "] should be one of " + Arrays.toString(ConsoleTarget.values()),
                this);
        status.add(new WarnStatus("Using previously set target, System.out by default.", this));
        addStatus(status);
    }

    @Override
    public void start() {
        OutputStream targetStream = target.getStream();
        // enable jansi only if withJansi set to true
        if (withJansi) {
            targetStream = wrapWithJansi(targetStream);
        }
        setOutputStream(targetStream);
        super.start();
    }

    private OutputStream wrapWithJansi(OutputStream targetStream) {
        try {
            addInfo("Enabling JANSI AnsiPrintStream for the console.");
            ClassLoader classLoader = Loader.getClassLoaderOfObject(context);
            Class classObj = classLoader.loadClass(AnsiConsole_CLASS_NAME);

            // check for JAnsi 2
            String methodNameJansi2 = target == ConsoleTarget.SystemOut ? JANSI2_OUT_METHOD_NAME
                    : JANSI2_ERR_METHOD_NAME;
            final Optional optOutMethod = Arrays.stream(classObj.getMethods())
                    .filter(m -> m.getName().equals(methodNameJansi2))
                    .filter(m -> m.getParameters().length == 0)
                    .filter(m -> Modifier.isStatic(m.getModifiers()))
                    .filter(m -> PrintStream.class.isAssignableFrom(m.getReturnType()))
                    .findAny();
            if (optOutMethod.isPresent()) {
                final Method outMethod = optOutMethod.orElseThrow(() -> new NoSuchElementException("No value present"));
                return (PrintStream) outMethod.invoke(null);
            }

            // JAnsi 1
            String methodName = target == ConsoleTarget.SystemOut ? wrapSystemOut_METHOD_NAME
                    : wrapSystemErr_METHOD_NAME;
            Method method = classObj.getMethod(methodName, ARGUMENT_TYPES);
            return (OutputStream) method.invoke(null, new PrintStream(targetStream));
        } catch (Exception e) {
            addWarn("Failed to create AnsiPrintStream. Falling back on the default stream.", e);
        }
        return targetStream;
    }

    /**
     * @return whether to use JANSI or not.
     */
    public boolean isWithJansi() {
        return withJansi;
    }

    /**
     * If true, this appender will output to a stream provided by the JANSI library.
     *
     * @param withJansi whether to use JANSI or not.
     * @since 1.0.5
     */
    public void setWithJansi(boolean withJansi) {
        this.withJansi = withJansi;
    }

}