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
  13 import eu.etaxonomy.cdm.model.agent.Person;
  14 import eu.etaxonomy.cdm.model.view.View;
  15 import org.apache.log4j.Logger;
  16 import org.hibernate.annotations.Cascade;
  17 import org.hibernate.annotations.CascadeType;
  18
  19 import java.util.*;
  20 import javax.persistence.*;
  21
  22 /**
  23  * 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.
  24  *
  25  * Full versioning allows concrete subclasses to keep track of previous or later versions of an object.
  26  * A different version is another (persistent) java object, but with the same UUID.
  27  * The version history is established as a linked list of the version objects in time.
  28  * If versioning via the linked list is used, updated/updatedBy is the same as created/createdBy (better NULL?).
  29  *
  30  * Versioning can be turned off and in this case this class provides updated/updatedBy to keep track of the latest change event.
  31  *
  32  * @author m.doering
  33  * @created 08-Nov-2007 13:07:01
  34  *
  35  * @param <T>
  36  */
  37 @MappedSuperclass
  38 public abstract class VersionableEntity<T extends VersionableEntity> extends CdmBase {
  39         static Logger logger = Logger.getLogger(VersionableEntity.class);
  40         //time of last update for this object
  41         private Calendar updated;
  42         private Person updatedBy;
  43         private T nextVersion;
  44         private T previousVersion;
  45
  46
  47         /**
  48          * Returns the succeeding version of this object with the same UUID
  49          * @return next, i.e. succeeding version of this object
  50          */
  51         //@OneToOne(mappedBy="previousVersion")
  52         @Transient
  53         public T getNextVersion(){
  54                 return this.nextVersion;
  55         }
  56         public void setNextVersion(T nextVersion){
  57                 this.nextVersion = nextVersion;
  58         }
  59
  60         //@OneToOne
  61         @Transient
  62         public T getPreviousVersion(){
  63                 return this.previousVersion;
  64         }
  65         public void setPreviousVersion(T previousVersion){
  66                 this.previousVersion = previousVersion;
  67         }
  68
  69
  70         @ManyToOne(fetch=FetchType.LAZY)
  71         @Cascade({CascadeType.SAVE_UPDATE})
  72         public Person getUpdatedBy(){
  73                 return this.updatedBy;
  74         }
  75
  76         /**
  77          *
  78          * @param updatedBy    updatedBy
  79          */
  80         public void setUpdatedBy(Person updatedBy){
  81                 this.updatedBy = updatedBy;
  82         }
  83
  84         /**
  85          *
  86          * @return
  87          */
  88         @Temporal(TemporalType.TIMESTAMP)
  89         @Version
  90         @Basic(fetch = FetchType.LAZY)
  91         public Calendar getUpdated(){
  92                 return this.updated;
  93         }
  94
  95         /**
  96          *
  97          * @param updated    updated
  98          */
  99         public void setUpdated(Calendar updated){
 100                 this.updated = updated;
 101         }
 102
 103         /**
 104          * based on created
 105          */
 106         @Transient
 107         public Calendar getValidFrom(){
 108                 return null;
 109         }
 110
 111         /**
 112          * based on updated
 113          */
 114         @Transient
 115         public Calendar getValidTo(){
 116                 return null;
 117         }
 118
 119         /**
 120          * Is true if UUID and created timestamp are the same for the passed Object and this one.
 121          * @see eu.etaxonomy.cdm.model.common.CdmBase#equals(java.lang.Object)
 122          * See {@link http://www.hibernate.org/109.html hibernate109}, {@link http://www.geocities.com/technofundo/tech/java/equalhash.html geocities}
 123          * or {@link http://www.ibm.com/developerworks/java/library/j-jtp05273.html ibm}
 124          * for more information about equals and hashcode.
 125          */
 126         @Override
 127         public boolean equals(Object obj) {
 128                 if (obj == this){
 129                         return true;
 130                 }
 131                 if (obj == null){
 132                         return false;
 133                 }
 134                 if (!CdmBase.class.isAssignableFrom(obj.getClass())){
 135                         return false;
 136                 }
 137                 ICdmBase cdmObj = (ICdmBase)obj;
 138                 boolean uuidEqual = cdmObj.getUuid().equals(this.getUuid());
 139                 boolean createdEqual = cdmObj.getCreated().equals(this.getCreated());
 140                 if (! uuidEqual || !createdEqual){
 141                                 return false;
 142                 }
 143                 return true;
 144         }
 145
 146
 147         /** Overrides {@link eu.etaxonomy.cdm.model.common.CdmBase#hashCode()}
 148          *  See {@link http://www.hibernate.org/109.html}, {@link http://www.geocities.com/technofundo/tech/java/equalhash.html}
 149          * or {@link http://www.ibm.com/developerworks/java/library/j-jtp05273.html}
 150          * for more information about equals and hashcode.
 151          */
 152          @Override
 153         public int hashCode() {
 154                    int hashCode = 7;
 155                    hashCode = 29 * hashCode + this.getUuid().hashCode();
 156                    //hashCode = 29 * hashCode + this.getCreated().hashCode();
 157                    return hashCode;
 158         }
 159
 160 }