/*
    * 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 org.apache.logging.log4j.core.appender;
  
  import java.io.Serializable;
  
  import org.apache.logging.log4j.core.Appender;
  import org.apache.logging.log4j.core.ErrorHandler;
  import org.apache.logging.log4j.core.Filter;
  import org.apache.logging.log4j.core.Layout;
  import org.apache.logging.log4j.core.LogEvent;
  import org.apache.logging.log4j.core.config.plugins.PluginBuilderAttribute;
  import org.apache.logging.log4j.core.config.plugins.PluginElement;
  import org.apache.logging.log4j.core.config.plugins.validation.constraints.Required;
  import org.apache.logging.log4j.core.filter.AbstractFilterable;
  import org.apache.logging.log4j.core.layout.PatternLayout;
  import org.apache.logging.log4j.core.util.Integers;
  
  /**
   * Abstract base class for Appenders. Although Appenders do not have to extend this class, doing so will simplify their
   * implementation.
   */
  public abstract class AbstractAppender extends AbstractFilterable implements Appender {
  
      /**
       * Subclasses can extend this abstract Builder. 
       * 
       * @param <B> This builder class.
       */
      public abstract static class Builder<B extends Builder<B>> extends AbstractFilterable.Builder<B> {
  
          @PluginBuilderAttribute
          private boolean ignoreExceptions = true;
          
          @PluginElement("Layout")
          private Layout<? extends Serializable> layout;
  
          @PluginBuilderAttribute
          @Required
          private String name;
  
          public String getName() {
              return name;
          }
  
          public boolean isIgnoreExceptions() {
              return ignoreExceptions;
          }
  
          public Layout<? extends Serializable> getLayout() {
              return layout;
          }
  
          public B withName(final String name) {
              this.name = name;
              return asBuilder();
          }
  
          public B withIgnoreExceptions(final boolean ignoreExceptions) {
              this.ignoreExceptions = ignoreExceptions;
              return asBuilder();
          }
  
          public B withLayout(final Layout<? extends Serializable> layout) {
              this.layout = layout;
              return asBuilder();
          }
  
          public Layout<? extends Serializable> getOrCreateLayout() {
              if (layout == null) {
                  return PatternLayout.createDefaultLayout();
              }
              return layout;
          }
          
      }
      
      private final String name;
      private final boolean ignoreExceptions;
      private final Layout<? extends Serializable> layout;
      private ErrorHandler handler = new DefaultErrorHandler(this);
  
      /**
       * Constructor that defaults to suppressing exceptions.
       * 
      * @param name The Appender name.
      * @param filter The Filter to associate with the Appender.
      * @param layout The layout to use to format the event.
      */
     protected AbstractAppender(final String name, final Filter filter, final Layout<? extends Serializable> layout) {
         this(name, filter, layout, true);
     }
 
     /**
      * Constructor.
      * 
      * @param name The Appender name.
      * @param filter The Filter to associate with the Appender.
      * @param layout The layout to use to format the event.
      * @param ignoreExceptions If true, exceptions will be logged and suppressed. If false errors will be logged and
      *            then passed to the application.
      */
     protected AbstractAppender(final String name, final Filter filter, final Layout<? extends Serializable> layout,
             final boolean ignoreExceptions) {
         super(filter);
         this.name = name;
         this.layout = layout;
         this.ignoreExceptions = ignoreExceptions;
     }
 
     public static int parseInt(final String s, final int defaultValue) {
         try {
             return Integers.parseInt(s, defaultValue);
         } catch (final NumberFormatException e) {
             LOGGER.error("Could not parse \"{}\" as an integer,  using default value {}: {}", s, defaultValue, e);
             return defaultValue;
         }
     }
 
     /**
      * Handle an error with a message using the {@link ErrorHandler} configured for this Appender.
      * 
      * @param msg The message.
      */
     public void error(final String msg) {
         handler.error(msg);
     }
 
     /**
      * Handle an error with a message, exception, and a logging event, using the {@link ErrorHandler} configured for
      * this Appender.
      * 
      * @param msg The message.
      * @param event The LogEvent.
      * @param t The Throwable.
      */
     public void error(final String msg, final LogEvent event, final Throwable t) {
         handler.error(msg, event, t);
     }
 
     /**
      * Handle an error with a message and an exception using the {@link ErrorHandler} configured for this Appender.
      * 
      * @param msg The message.
      * @param t The Throwable.
      */
     public void error(final String msg, final Throwable t) {
         handler.error(msg, t);
     }
 
     /**
      * Returns the ErrorHandler, if any.
      * 
      * @return The ErrorHandler.
      */
     @Override
     public ErrorHandler getHandler() {
         return handler;
     }
 
     /**
      * Returns the Layout for the appender.
      * 
      * @return The Layout used to format the event.
      */
     @Override
     public Layout<? extends Serializable> getLayout() {
         return layout;
     }
 
     /**
      * Returns the name of the Appender.
      * 
      * @return The name of the Appender.
      */
     @Override
     public String getName() {
         return name;
     }
 
     /**
      * Some appenders need to propagate exceptions back to the application. When {@code ignoreExceptions} is
      * {@code false} the AppenderControl will allow the exception to percolate.
      *
      * @return {@code true} if exceptions will be logged but now thrown, {@code false} otherwise.
      */
     @Override
     public boolean ignoreExceptions() {
         return ignoreExceptions;
     }
 
     /**
      * The handler must be set before the appender is started.
      * 
      * @param handler The ErrorHandler to use.
      */
     @Override
     public void setHandler(final ErrorHandler handler) {
         if (handler == null) {
             LOGGER.error("The handler cannot be set to null");
         }
         if (isStarted()) {
             LOGGER.error("The handler cannot be changed once the appender is started");
             return;
         }
         this.handler = handler;
     }
 
     @Override
     public String toString() {
         return name;
     }
 
 }