/*
    * 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.message;
  
  import java.io.IOException;
  import java.io.ObjectInputStream;
  import java.io.ObjectOutputStream;
  import java.io.Serializable;
  
  import org.apache.logging.log4j.util.StringBuilderFormattable;
  
  /**
   * Handles messages that contain an Object.
   */
  public class ObjectMessage implements Message, StringBuilderFormattable {
  
      private static final long serialVersionUID = -5903272448334166185L;
  
      private transient Object obj;
      private transient String objectString;
  
      /**
       * Creates the ObjectMessage.
       *
       * @param obj The Object to format.
       */
      public ObjectMessage(final Object obj) {
          this.obj = obj == null ? "null" : obj;
      }
  
      /**
       * Returns the formatted object message.
       *
       * @return the formatted object message.
       */
      @Override
      public String getFormattedMessage() {
          // LOG4J2-763: cache formatted string in case obj changes later
          if (objectString == null) {
              objectString = String.valueOf(obj);
          }
          return objectString;
      }
  
      @Override
      public void formatTo(final StringBuilder buffer) {
          if (obj == null || obj instanceof String) {
              buffer.append((String) obj);
          } else if (obj instanceof StringBuilderFormattable) {
              ((StringBuilderFormattable) obj).formatTo(buffer);
          } else if (obj instanceof CharSequence) {
              buffer.append((CharSequence) obj);
          } else {
              buffer.append(obj);
          }
      }
  
      /**
       * Returns the object formatted using its toString method.
       *
       * @return the String representation of the object.
       */
      @Override
      public String getFormat() {
          return getFormattedMessage();
      }
  
      /**
       * Returns the object as if it were a parameter.
       *
       * @return The object.
       */
      @Override
      public Object[] getParameters() {
          return new Object[] {obj};
      }
  
      @Override
      public boolean equals(final Object o) {
          if (this == o) {
              return true;
          }
          if (o == null || getClass() != o.getClass()) {
              return false;
          }
 
         final ObjectMessage that = (ObjectMessage) o;
         return obj == null ? that.obj == null : equalObjectsOrStrings(obj, that.obj);
     }
 
     private boolean equalObjectsOrStrings(final Object left, final Object right) {
         return left.equals(right) || String.valueOf(left).equals(String.valueOf(right));
     }
 
     @Override
     public int hashCode() {
         return obj != null ? obj.hashCode() : 0;
     }
 
     @Override
     public String toString() {
         return getFormattedMessage();
     }
 
     private void writeObject(final ObjectOutputStream out) throws IOException {
         out.defaultWriteObject();
         if (obj instanceof Serializable) {
             out.writeObject(obj);
         } else {
             out.writeObject(String.valueOf(obj));
         }
     }
 
     private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
         in.defaultReadObject();
         obj = in.readObject();
     }
 
     /**
      * Gets the message if it is a throwable.
      *
      * @return the message if it is a throwable.
      */
     @Override
     public Throwable getThrowable() {
         return obj instanceof Throwable ? (Throwable) obj : null;
     }
 }