/*
    * Copyright 2007-2013 smartics, Kronseder & Reiner GmbH
    *
    * Licensed 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 de.smartics.exceptions;
  
  import java.io.Serializable;
  import java.util.Date;
  
  import de.smartics.exceptions.core.Code;
  import de.smartics.exceptions.core.ExceptionId;
  import de.smartics.exceptions.core.IdFactory;
  import de.smartics.exceptions.core.ThrowableHandleMode;
  import de.smartics.exceptions.runtime.ExceptionContextManager;
  
  /**
   * Contains the information commonly used by runtime and checked exceptions.
   */
  class ExceptionInfo implements Serializable
  {
    // ********************************* Fields *********************************
  
    // --- constants ------------------------------------------------------------
  
    /**
     * The class version identifier.
     */
    private static final long serialVersionUID = 3L;
  
    // --- members --------------------------------------------------------------
  
    /**
     * The reference to the cause is stored to be able to remove it later. This is
     * useful to strip all Exceptions from the cause that are not suited to be
     * transfered to a remote destination. Especially exceptions of server side
     * packages can be removed to be not sent to the client.
     *
     * @note Instances of this class are supposed to be referenced by exception
     *       instances and should therefore be constant value objects. The feature
     *       of truncation requires this field to be none-final. It is protected
     *       to allow only members of the package to manipulate it.
     * @serial
     */
    protected Throwable removeableCause;
  
    /**
     * The unique identifier of the exception. The identifier is used to track an
     * exception in different tiers.
     * <p>
     * This identifier must never be <code>null</code>.
     *
     * @serial
     */
    protected final ExceptionId<?> id;
  
    /**
     * The error or exception code of the exception.
     * <p>
     * This code must never be <code>null</code>.
     *
     * @serial
     */
    protected final Code code;
  
    /**
     * The time the exception has been raised. The time instance is created and
     * stored as soon as the exception is constructed.
     *
     * @serial
     */
    private final Date time;
  
    // ****************************** Initializer *******************************
  
    // ****************************** Constructors ******************************
  
    /**
     * Default constructor.
     *
     * @param cause the cause (which is saved for later retrieval by the
     *          {@link #getCause()} method). (A <tt>null</tt> value is permitted,
     *          and indicates that the cause is nonexistent or unknown.)
     * @param code the error or exception code of the exception.
     * @throws NullPointerException if the code is <code>null</code>.
     */
    protected ExceptionInfo(final Throwable cause, final Code code)
        throws NullPointerException
    {
     if (code == null)
     {
       throw new NullPointerException("The code must not be 'null'!");
     }
     this.removeableCause = Helper.getThrowableHandleMode() != ThrowableHandleMode.NORMAL
         ? cause : null;
     this.time = new Date();
     this.id = provideId(cause);
     this.code = code;
   }
 
   // ****************************** Inner Classes *****************************
 
   // ********************************* Methods ********************************
 
   // --- init -----------------------------------------------------------------
 
   /**
    * Checks if the cause already has an UUID and returns it if present.
    * Otherwise it returns a new generated UUID.
    *
    * @param cause the cause to check for an identifier.
    * @return the UUID of the given cause if it has one, a new UUID otherwise.
    */
   private static ExceptionId<?> provideId(final Throwable cause)
   {
     ExceptionId<?> id = Helper.determineParentId(cause);
 
     if (id == null)
     {
       final IdFactory factory = ExceptionContextManager.getFactory(Thread
           .currentThread().getContextClassLoader());
       id = factory.createId();
     }
 
     return id;
   }
 
   // --- get&set --------------------------------------------------------------
 
   /**
    * Returns the unique identifier of the exception. The identifier is used to
    * track an exception in different tiers.
    * <p>
    * This identifier must never be <code>null</code>.
    * </p>
    *
    * @return the unique identifier of the exception.
    */
   public ExceptionId<?> getId()
   {
     return this.id;
   }
 
   /**
    * Returns the error or exception code of the exception.
    * <p>
    * This code must never be <code>null</code>.
    * </p>
    *
    * @return the error or exception code of the exception.
    */
   public Code getCode()
   {
     return this.code;
   }
 
   /**
    * Returns the time the exception has been raised. The time instance is
    * created and stored as soon as the exception is constructed.
    *
    * @return the time the exception has been raised.
    */
   public Date getTime()
   {
     return time;
   }
 
   // --- business -------------------------------------------------------------
 
   // --- object basics --------------------------------------------------------
 
   /**
    * {@inheritDoc}
    * <p>
    * Returns the identifier, code and time information as a {@link String}.
    * </p>
    */
   @Override
   public String toString()
   {
     return this.id + " (" + this.code + ") - " + time;
   }
 }