//
   //  ========================================================================
   //  Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd.
   //  ------------------------------------------------------------------------
   //  All rights reserved. This program and the accompanying materials
   //  are made available under the terms of the Eclipse Public License v1.0
   //  and Apache License v2.0 which accompanies this distribution.
   //
   //      The Eclipse Public License is available at
  //      http://www.eclipse.org/legal/epl-v10.html
  //
  //      The Apache License v2.0 is available at
  //      http://www.opensource.org/licenses/apache2.0.php
  //
  //  You may elect to redistribute this code under either of these licenses.
  //  ========================================================================
  //
  
  package org.eclipse.jetty.util;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  /** 
   * Wraps multiple exceptions.
   *
   * Allows multiple exceptions to be thrown as a single exception.
   */
  @SuppressWarnings("serial")
  public class MultiException extends Exception
  {
      private List<Throwable> nested;
  
      /* ------------------------------------------------------------ */
      public MultiException()
      {
          super("Multiple exceptions");
      }
  
      /* ------------------------------------------------------------ */
      public void add(Throwable e)
      {
          if (e==null)
              throw new IllegalArgumentException();
  
          if(nested == null)
          {
              initCause(e);
              nested = new ArrayList<>();
          }
          else
              addSuppressed(e);
          
          if (e instanceof MultiException)
          {
              MultiException me = (MultiException)e;
              nested.addAll(me.nested);
          }
          else
              nested.add(e);
      }
  
      /* ------------------------------------------------------------ */
      public int size()
      {
          return (nested ==null)?0:nested.size();
      }
      
      /* ------------------------------------------------------------ */
      public List<Throwable> getThrowables()
      {
          if(nested == null)
              return Collections.emptyList();
          return nested;
      }
      
      /* ------------------------------------------------------------ */
      public Throwable getThrowable(int i)
      {
          return nested.get(i);
      }
  
      /* ------------------------------------------------------------ */
      /** Throw a multiexception.
       * If this multi exception is empty then no action is taken. If it
       * contains a single exception that is thrown, otherwise the this
       * multi exception is thrown. 
       * @exception Exception 
       */
      public void ifExceptionThrow()
          throws Exception
      {
          if(nested == null)
              return;
          
          switch (nested.size())
          {
            case 0:
               break;
           case 1:
               Throwable th=nested.get(0);
               if (th instanceof Error)
                   throw (Error)th;
               if (th instanceof Exception)
                   throw (Exception)th;
           default:
               throw this;
         }
     }
     
     /* ------------------------------------------------------------ */
     /** Throw a Runtime exception.
      * If this multi exception is empty then no action is taken. If it
      * contains a single error or runtime exception that is thrown, otherwise the this
      * multi exception is thrown, wrapped in a runtime exception. 
      * @exception Error If this exception contains exactly 1 {@link Error} 
      * @exception RuntimeException If this exception contains 1 {@link Throwable} but it is not an error,
      *                             or it contains more than 1 {@link Throwable} of any type.
      */
     public void ifExceptionThrowRuntime()
         throws Error
     {
         if(nested == null)
             return;
         
         switch (nested.size())
         {
           case 0:
               break;
           case 1:
               Throwable th=nested.get(0);
               if (th instanceof Error)
                   throw (Error)th;
               else if (th instanceof RuntimeException)
                   throw (RuntimeException)th;
               else
                   throw new RuntimeException(th);
           default:
               throw new RuntimeException(this);
         }
     }
     
     /* ------------------------------------------------------------ */
     /** Throw a multiexception.
      * If this multi exception is empty then no action is taken. If it
      * contains a any exceptions then this
      * multi exception is thrown. 
      */
     public void ifExceptionThrowMulti()
         throws MultiException
     {
         if(nested == null)
             return;
         
         if (nested.size()>0)
             throw this;
     }
 
     /* ------------------------------------------------------------ */
     @Override
     public String toString()
     {
         StringBuilder str = new StringBuilder();
         str.append(MultiException.class.getSimpleName());
         if((nested == null) || (nested.size()<=0)) {
             str.append("[]");
         } else {
             str.append(nested);
         }
         return str.toString();
     }
 
 }