/**
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2011, 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 ch.qos.logback.core.joran.action;
  
  import java.util.HashMap;
  
  import org.xml.sax.Attributes;
  
  import ch.qos.logback.core.Appender;
  import ch.qos.logback.core.joran.spi.ActionException;
  import ch.qos.logback.core.joran.spi.InterpretationContext;
  import ch.qos.logback.core.spi.LifeCycle;
  import ch.qos.logback.core.util.OptionHelper;
  
  public class AppenderAction<E> extends Action {
    Appender<E> appender;
    private boolean inError = false;
  
    /**
     * Instantiates an appender of the given class and sets its name.
     * 
     * The appender thus generated is placed in the {@link InterpretationContext}'s
     * appender bag.
     */
    @SuppressWarnings("unchecked")
    public void begin(InterpretationContext ec, String localName,
        Attributes attributes) throws ActionException {
      // We are just beginning, reset variables
      appender = null;
      inError = false;
  
      String className = attributes.getValue(CLASS_ATTRIBUTE);
      if (OptionHelper.isEmpty(className)) {
        addError("Missing class name for appender. Near [" + localName
            + "] line " + getLineNumber(ec));
        inError = true;
        return;
      }
  
      try {
        addInfo("About to instantiate appender of type [" + className + "]");
  
        appender = (Appender) OptionHelper.instantiateByClassName(className,
            ch.qos.logback.core.Appender.class, context);
  
        appender.setContext(context);
  
        String appenderName = ec.subst(attributes.getValue(NAME_ATTRIBUTE));
  
        if (OptionHelper.isEmpty(appenderName)) {
          addWarn("No appender name given for appender of type " + className
              + "].");
        } else {
          appender.setName(appenderName);
          addInfo("Naming appender as [" + appenderName + "]");
        }
  
        // The execution context contains a bag which contains the appenders
        // created thus far.
        HashMap<String, Appender> appenderBag = (HashMap) ec.getObjectMap().get(
            ActionConst.APPENDER_BAG);
  
        // add the appender just created to the appender bag.
        appenderBag.put(appenderName, appender);
  
        ec.pushObject(appender);
      } catch (Exception oops) {
        inError = true;
        addError("Could not create an Appender of type [" + className + "].",
            oops);
        throw new ActionException(oops);
      }
    }
  
    /**
     * Once the children elements are also parsed, now is the time to activate the
     * appender options.
     */
    public void end(InterpretationContext ec, String name) {
      if (inError) {
        return;
      }
  
      if (appender instanceof LifeCycle) {
        ((LifeCycle) appender).start();
      }
  
      Object o = ec.peekObject();
 
     if (o != appender) {
       addWarn("The object at the of the stack is not the appender named ["
           + appender.getName() + "] pushed earlier.");
     } else {
       ec.popObject();
     }
   }
 }