package com.atlassian.sal.api.events;
   
   import javax.annotation.Nullable;
   import javax.annotation.concurrent.Immutable;
   import javax.servlet.http.HttpSessionListener;
   
   /**
    * Represents an event published when a http session is destroyed.  Implementers should fire this event accordingly.
    * @see HttpSessionListener
   */
  @Immutable
  public class SessionDestroyedEvent
  {
      private final String sessionId;
      private final String userName;
  
      private SessionDestroyedEvent(final String sessionId, final String userName)
      {
          this.sessionId = sessionId;
          this.userName = userName;
      }
  
      public static Builder builder()
      {
          return new Builder();
      }
  
      public String getSessionId()
      {
          return sessionId;
      }
  
      @Nullable
      public String getUserName()
      {
          return userName;
      }
  
      public static class Builder
      {
          private String sessionId;
          private String userName;
  
          private Builder()
          {
          }
  
          public Builder sessionId(final String sessionId)
          {
              if (sessionId == null)
              {
                  throw new NullPointerException("Session ID must be supplied");
              }
              this.sessionId = sessionId;
              return this;
          }
  
          public Builder userName(@Nullable final String userName)
          {
              this.userName = userName;
              return this;
          }
  
  
          public SessionDestroyedEvent build()
          {
              if (sessionId == null)
              {
                  throw new NullPointerException("Session ID must be supplied");
              }
              return new SessionDestroyedEvent(sessionId, userName);
          }
      }
  
  }