/*
    * ModeShape (http://www.modeshape.org)
    * See the COPYRIGHT.txt file distributed with this work for information
    * regarding copyright ownership.  Some portions may be licensed
    * to Red Hat, Inc. under one or more contributor license agreements.
    * See the AUTHORS.txt file in the distribution for a full listing of 
    * individual contributors.
    *
    * ModeShape is free software. Unless otherwise indicated, all code in ModeShape
   * is licensed to you under the terms of the GNU Lesser General Public License as
   * published by the Free Software Foundation; either version 2.1 of
   * the License, or (at your option) any later version.
   * 
   * ModeShape is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this software; if not, write to the Free
   * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
   * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
   */
  package org.modeshape.graph.observe;
  
  import java.io.Serializable;
  import java.util.Collections;
  import java.util.List;
  import net.jcip.annotations.Immutable;
  import org.modeshape.graph.ExecutionContext;
  import org.modeshape.graph.SecurityContext;
  import org.modeshape.graph.property.DateTime;
  import org.modeshape.graph.request.ChangeRequest;
  
  /**
   * A set of changes that were made atomically. Each change is in the form of a frozen {@link ChangeRequest}.
   */
  @Immutable
  public class Changes implements Comparable<Changes>, Serializable {
  
      private static final long serialVersionUID = 1L;
  
      protected final String processId;
      protected final String contextId;
      protected final String userName;
      protected final String sourceName;
      protected final DateTime timestamp;
      protected final List<ChangeRequest> changeRequests;
  
      public Changes( String processId,
                      String contextId,
                      String userName,
                      String sourceName,
                      DateTime timestamp,
                      List<ChangeRequest> requests ) {
          assert requests != null;
          assert !requests.isEmpty();
          this.userName = userName;
          this.sourceName = sourceName;
          this.timestamp = timestamp;
          this.changeRequests = Collections.unmodifiableList(requests);
          this.processId = processId != null ? processId : "";
          this.contextId = contextId != null ? contextId : "";
          assert this.userName != null;
          assert this.sourceName != null;
          assert this.timestamp != null;
          assert this.changeRequests != null;
          assert this.processId != null;
      }
  
      protected Changes( Changes changes ) {
          this.userName = changes.userName;
          this.sourceName = changes.sourceName;
          this.timestamp = changes.timestamp;
          this.changeRequests = changes.changeRequests;
          this.processId = changes.processId;
          this.contextId = changes.contextId;
          assert this.userName != null;
          assert this.sourceName != null;
          assert this.timestamp != null;
          assert this.changeRequests != null;
          assert this.processId != null;
          assert this.contextId != null;
      }
  
      /**
       * Get the user that made these changes.
       * 
       * @return the user; never null
       * @see SecurityContext#getUserName()
       */
      public String getUserName() {
          return this.userName;
      }
  
      /**
       * Get the name of the source that was changed.
       * 
       * @return the source name; never null
      */
     public String getSourceName() {
         return this.sourceName;
     }
 
     /**
      * Get the timestamp that the changes were made. All changes within the change set were all made at this instant in time.
      * 
      * @return the timestamp of the changes; never null
      */
     public DateTime getTimestamp() {
         return this.timestamp;
     }
 
     /**
      * Get the identifier of the process where these changes originated. This identifier may be useful in preventing feedbacks.
      * 
      * @return the process identifier; never null
      */
     public String getProcessId() {
         return processId;
     }
 
     /**
      * Get the {@link ExecutionContext#getId() identifier} of the {@link ExecutionContext} where these changes originated. This
      * identifier may be useful in preventing feedbacks.
      * 
      * @return the context identifier; never null
      */
     public String getContextId() {
         return contextId;
     }
 
     /**
      * Get the list of changes.
      * 
      * @return the immutable list of change requests; never null and never empty
      */
     public List<ChangeRequest> getChangeRequests() {
         return changeRequests;
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see java.lang.Object#hashCode()
      */
     @Override
     public int hashCode() {
         return getTimestamp().hashCode();
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see java.lang.Comparable#compareTo(java.lang.Object)
      */
     public int compareTo( Changes that ) {
         if (this == that) return 0;
         return this.getTimestamp().compareTo(that.getTimestamp());
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see java.lang.Object#equals(java.lang.Object)
      */
     @Override
     public boolean equals( Object obj ) {
         if (obj == this) return true;
         if (obj instanceof Changes) {
             Changes that = (Changes)obj;
             if (!this.getProcessId().equals(that.getProcessId())) return false;
             if (!this.getContextId().equals(that.getContextId())) return false;
             if (!this.getSourceName().equals(that.getSourceName())) return false;
             if (!this.getTimestamp().equals(that.getTimestamp())) return false;
             if (!this.getUserName().equals(that.getUserName())) return false;
             return true;
         }
         return false;
     }
 
     /**
      * {@inheritDoc}
      * 
      * @see java.lang.Object#toString()
      */
     @Override
     public String toString() {
         if (processId.length() != 0) {
             return getTimestamp() + " @" + getUserName() + " [" + getSourceName() + "] - " + changeRequests.size() + " events";
         }
         return getTimestamp() + " @" + getUserName() + " #" + getProcessId() + " [" + getSourceName() + "] - "
                + changeRequests.size() + " events";
     }
 }