cdmlib-model/src/main/java/eu/etaxonomy/cdm/model/common/VersionableEntity.java

   1 /**
   2 * Copyright (C) 2007 EDIT
   3 * European Distributed Institute of Taxonomy
   4 * http://www.e-taxonomy.eu
   5 *
   6 * The contents of this file are subject to the Mozilla Public License Version 1.1
   7 * See LICENSE.TXT at the top of this package for the full license terms.
   8 */
   9
  10 package eu.etaxonomy.cdm.model.common;
  11
  12 import eu.etaxonomy.cdm.model.agent.Person;
  13 import org.apache.log4j.Logger;
  14 import org.hibernate.annotations.Cascade;
  15 import org.hibernate.annotations.CascadeType;
  16
  17 import java.util.*;
  18 import javax.persistence.*;
  19
  20 /**
  21  * The class keeps track of versions via a full linked list to different version objects, or a simple updated/updatedBy property in the same object.
  22  *
  23  * Full versioning allows concrete subclasses to keep track of previous or later versions of an object.
  24  * A different version is another (persistent) java object, but with the same UUID.
  25  * The version history is established as a linked list of the version objects in time.
  26  * If versioning via the linked list is used, updated/updatedBy is the same as created/createdBy (better NULL?).
  27  *
  28  * Versioning can be turned off and in this case this class provides updated/updatedBy to keep track of the latest change event.
  29  *
  30  * @author m.doering
  31  * @created 08-Nov-2007 13:07:01
  32  *
  33  * @param <T>
  34  */
  35 @MappedSuperclass
  36 public abstract class VersionableEntity<T extends VersionableEntity> extends CdmBase {
  37         private static final Logger logger = Logger.getLogger(VersionableEntity.class);
  38
  39         //time of last update for this object
  40         private Calendar updated;
  41         private Person updatedBy;
  42         private T nextVersion;
  43         private T previousVersion;
  44
  45
  46         /**
  47          * Returns the succeeding version of this object with the same UUID
  48          * @return next, i.e. succeeding version of this object
  49          */
  50         //@OneToOne(mappedBy="previousVersion")
  51         @Transient
  52         public T getNextVersion(){
  53                 return this.nextVersion;
  54         }
  55         public void setNextVersion(T nextVersion){
  56                 this.nextVersion = nextVersion;
  57         }
  58
  59         //@OneToOne
  60         @Transient
  61         public T getPreviousVersion(){
  62                 return this.previousVersion;
  63         }
  64         public void setPreviousVersion(T previousVersion){
  65                 this.previousVersion = previousVersion;
  66         }
  67
  68
  69         @ManyToOne(fetch=FetchType.LAZY)
  70         @Cascade({CascadeType.SAVE_UPDATE})
  71         public Person getUpdatedBy(){
  72                 return this.updatedBy;
  73         }
  74
  75         /**
  76          *
  77          * @param updatedBy    updatedBy
  78          */
  79         public void setUpdatedBy(Person updatedBy){
  80                 this.updatedBy = updatedBy;
  81         }
  82
  83         /**
  84          *
  85          * @return
  86          */
  87         @Temporal(TemporalType.TIMESTAMP)
  88         @Version
  89         @Basic(fetch = FetchType.LAZY)
  90         public Calendar getUpdated(){
  91                 return this.updated;
  92         }
  93
  94         /**
  95          *
  96          * @param updated    updated
  97          */
  98         public void setUpdated(Calendar updated){
  99                 this.updated = updated;
 100         }
 101
 102         /**
 103          * based on created
 104          */
 105         @Transient
 106         public Calendar getValidFrom(){
 107                 return null;
 108         }
 109
 110         /**
 111          * based on updated
 112          */
 113         @Transient
 114         public Calendar getValidTo(){
 115                 return null;
 116         }
 117
 118         /**
 119          * Is true if UUID and created timestamp are the same for the passed Object and this one.
 120          * @see eu.etaxonomy.cdm.model.common.CdmBase#equals(java.lang.Object)
 121          * See {@link http://www.hibernate.org/109.html hibernate109}, {@link http://www.geocities.com/technofundo/tech/java/equalhash.html geocities}
 122          * or {@link http://www.ibm.com/developerworks/java/library/j-jtp05273.html ibm}
 123          * for more information about equals and hashcode.
 124          */
 125         @Override
 126         public boolean equals(Object obj) {
 127                 if (obj == this){
 128                         return true;
 129                 }
 130                 if (obj == null){
 131                         return false;
 132                 }
 133                 if (!CdmBase.class.isAssignableFrom(obj.getClass())){
 134                         return false;
 135                 }
 136                 ICdmBase cdmObj = (ICdmBase)obj;
 137                 boolean uuidEqual = cdmObj.getUuid().equals(this.getUuid());
 138                 boolean createdEqual = cdmObj.getCreated().equals(this.getCreated());
 139                 if (! uuidEqual || !createdEqual){
 140                                 return false;
 141                 }
 142                 return true;
 143         }
 144
 145
 146         /** Overrides {@link eu.etaxonomy.cdm.model.common.CdmBase#hashCode()}
 147          *  See {@link http://www.hibernate.org/109.html}, {@link http://www.geocities.com/technofundo/tech/java/equalhash.html}
 148          * or {@link http://www.ibm.com/developerworks/java/library/j-jtp05273.html}
 149          * for more information about equals and hashcode.
 150          */
 151          @Override
 152         public int hashCode() {
 153                    int hashCode = 7;
 154                    hashCode = 29 * hashCode + this.getUuid().hashCode();
 155                    //hashCode = 29 * hashCode + this.getCreated().hashCode();
 156                    return hashCode;
 157         }
 158
 159 }