AppenderRefModelHandler.java

/*
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 1999-2026, QOS.ch. All rights reserved.
 *
 * This program and the accompanying materials are dual-licensed under
 * either the terms of the Eclipse Public License v2.0 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 ch.qos.logback.core.model.processor;

import ch.qos.logback.core.Appender;
import ch.qos.logback.core.Context;
import ch.qos.logback.core.joran.JoranConstants;
import ch.qos.logback.core.model.AppenderRefModel;
import ch.qos.logback.core.model.Model;
import ch.qos.logback.core.spi.AppenderAttachable;

import java.util.Map;

import static ch.qos.logback.core.model.processor.AppenderDeclarationAnalyser.isAppenderDeclared;

public class AppenderRefModelHandler extends ModelHandlerBase {
    boolean inError = false;

    public AppenderRefModelHandler(Context context) {
        super(context);
    }

    static public ModelHandlerBase makeInstance(Context context, ModelInterpretationContext ic) {
        return new AppenderRefModelHandler(context);
    }

    @Override
    protected Class<? extends AppenderRefModel> getSupportedModelClass() {
        return AppenderRefModel.class;
    }

    @Override
    public void handle(ModelInterpretationContext interpContext, Model model) throws ModelHandlerException {

        Object o = interpContext.peekObject();

        if (!(o instanceof AppenderAttachable)) {
            inError = true;
            String errMsg = "Could not find an AppenderAttachable at the top of execution stack. Near "
                    + model.idString();
            addError(errMsg);
            return;
        }

        AppenderRefModel appenderRefModel = (AppenderRefModel) model;
        AppenderAttachable<?> appenderAttachable = (AppenderAttachable<?>) o;

        attachReferencedAppenders(interpContext, appenderRefModel, appenderAttachable);

    }

    @SuppressWarnings({ "unchecked", "rawtypes" })
    void attachReferencedAppenders(ModelInterpretationContext mic, AppenderRefModel appenderRefModel,
            AppenderAttachable<?> appenderAttachable) {
        String appenderName = mic.subst(appenderRefModel.getRef());

        if(!isAppenderDeclared(mic, appenderName)) {
            addWarn("Appender named [" + appenderName + "] could not be found. Skipping attachment to "+appenderAttachable+".");
            return;
        }

        Map<String, Appender> appenderBag = (Map<String, Appender>) mic.getObjectMap().get(JoranConstants.APPENDER_BAG);

        Appender appender = appenderBag.get(appenderName);
        if (appender == null) {
            addError("Failed to find appender named [" + appenderName + "]");
        } else {
            addInfo("Attaching appender named [" + appenderName + "] to " + appenderAttachable);
            appenderAttachable.addAppender(appender);
        }

    }
}