/*
    * 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.layout;
  
  import java.io.Serializable;
  import java.util.HashMap;
  import java.util.Map;
  
  import org.apache.logging.log4j.Logger;
  import org.apache.logging.log4j.core.Layout;
  import org.apache.logging.log4j.core.LogEvent;
  import org.apache.logging.log4j.core.config.Configuration;
  import org.apache.logging.log4j.core.config.plugins.PluginBuilderAttribute;
  import org.apache.logging.log4j.core.config.plugins.PluginConfiguration;
  import org.apache.logging.log4j.status.StatusLogger;
  
  /**
   * Abstract base class for Layouts.
   *
   * @param <T>
   *            The Class that the Layout will format the LogEvent into.
   */
  public abstract class AbstractLayout<T extends Serializable> implements Layout<T> {
  
      /**
       * Subclasses can extend this abstract Builder.
       *
       * @param <B> The type to build.
       */
      public abstract static class Builder<B extends Builder<B>> {
  
          @PluginConfiguration
          private Configuration configuration;
  
          @PluginBuilderAttribute
          private byte[] footer;
  
          @PluginBuilderAttribute
          private byte[] header;
  
          @SuppressWarnings("unchecked")
          public B asBuilder() {
              return (B) this;
          }
  
          public Configuration getConfiguration() {
              return configuration;
          }
  
          public byte[] getFooter() {
              return footer;
          }
  
          public byte[] getHeader() {
              return header;
          }
  
          public B setConfiguration(final Configuration configuration) {
              this.configuration = configuration;
              return asBuilder();
          }
  
          public B setFooter(final byte[] footer) {
              this.footer = footer;
              return asBuilder();
          }
  
          public B setHeader(final byte[] header) {
              this.header = header;
              return asBuilder();
          }
  
      }
  
      /**
       * Allow subclasses access to the status logger without creating another instance.
       */
      protected static final Logger LOGGER = StatusLogger.getLogger();
  
      /**
       * The current Configuration.
       */
      protected final Configuration configuration;
  
      /**
      * The number of events successfully processed by this layout.
      */
     protected long eventCount;
 
     /**
      * The footer to add when the stream is closed. May be null.
      */
     protected final byte[] footer;
 
     /**
      * The header to include when the stream is opened. May be null.
      */
     protected final byte[] header;
 
     /**
      * Constructs a layout with an optional header and footer.
      *
      * @param header
      *            The header to include when the stream is opened. May be null.
      * @param footer
      *            The footer to add when the stream is closed. May be null.
      * @deprecated Use {@link #AbstractLayout(Configuration, byte[], byte[])}
      */
     @Deprecated
     public AbstractLayout(final byte[] header, final byte[] footer) {
         this(null, header, footer);
     }
 
     /**
      * Constructs a layout with an optional header and footer.
      *
      * @param configuration
      *            The configuration
      * @param header
      *            The header to include when the stream is opened. May be null.
      * @param footer
      *            The footer to add when the stream is closed. May be null.
      */
     public AbstractLayout(final Configuration configuration, final byte[] header, final byte[] footer) {
         super();
         this.configuration = configuration;
         this.header = header;
         this.footer = footer;
     }
 
     public Configuration getConfiguration() {
         return configuration;
     }
 
     @Override
     public Map<String, String> getContentFormat() {
         return new HashMap<>();
     }
 
     /**
      * Returns the footer, if one is available.
      *
      * @return A byte array containing the footer.
      */
     @Override
     public byte[] getFooter() {
         return footer;
     }
 
     /**
      * Returns the header, if one is available.
      *
      * @return A byte array containing the header.
      */
     @Override
     public byte[] getHeader() {
         return header;
     }
 
     protected void markEvent() {
         eventCount++;
     }
 
     /**
      * Encodes the specified source LogEvent to some binary representation and writes the result to the specified
      * destination.
      * <p>
      * The default implementation of this method delegates to the {@link #toByteArray(LogEvent)} method which allocates
      * temporary objects.
      * </p><p>
      * Subclasses can override this method to provide a garbage-free implementation. For text-based layouts,
      * {@code AbstractStringLayout} provides various convenience methods to help with this:
      * </p>
      * <pre>@Plugin(name = "MyLayout", category = Node.CATEGORY, elementType = Layout.ELEMENT_TYPE, printObject = true)
      * public final class MyLayout extends AbstractStringLayout {
      *     @Override
      *     public void encode(LogEvent event, ByteBufferDestination destination) {
      *         StringBuilder text = getStringBuilder();
      *         convertLogEventToText(event, text);
      *         getStringBuilderEncoder().encode(text, destination);
      *     }
      *
      *     private void convertLogEventToText(LogEvent event, StringBuilder destination) {
      *         ... // append a text representation of the log event to the StringBuilder
      *     }
      * }
      * </pre>
      *
      * @param event the LogEvent to encode.
      * @param destination holds the ByteBuffer to write into.
      * @see AbstractStringLayout#getStringBuilder()
      * @see AbstractStringLayout#getStringBuilderEncoder()
      */
     @Override
     public void encode(final LogEvent event, final ByteBufferDestination destination) {
         final byte[] data = toByteArray(event);
         destination.writeBytes(data, 0, data.length);
     }
 }