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
  19 import javax.persistence.*;
  20 import javax.xml.bind.annotation.XmlAccessType;
  21 import javax.xml.bind.annotation.XmlAccessorType;
  22 import javax.xml.bind.annotation.XmlElement;
  23 import javax.xml.bind.annotation.XmlRootElement;
  24 import javax.xml.bind.annotation.XmlTransient;
  25 import javax.xml.bind.annotation.XmlType;
  26
  27 /**
  28  * 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.
  29  *
  30  * Full versioning allows concrete subclasses to keep track of previous or later versions of an object.
  31  * A different version is another (persistent) java object, but with the same UUID.
  32  * The version history is established as a linked list of the version objects in time.
  33  * If versioning via the linked list is used, updated/updatedBy is the same as created/createdBy (better NULL?).
  34  *
  35  * Versioning can be turned off and in this case this class provides updated/updatedBy to keep track of the latest change event.
  36  *
  37  * @author m.doering
  38  * @created 08-Nov-2007 13:07:01
  39  *
  40  * @param <T>
  41  */
  42 @XmlAccessorType(XmlAccessType.FIELD)
  43 @XmlType(name = "VersionableEntity", propOrder = {
  44 //    "updated",
  45     "updatedBy",
  46     "nextVersion",
  47     "previousVersion"
  48 })
  49 @XmlRootElement(name = "VersionableEntity")
  50 @MappedSuperclass
  51 public abstract class VersionableEntity<T extends VersionableEntity> extends CdmBase {
  52         private static final Logger logger = Logger.getLogger(VersionableEntity.class);
  53
  54         //time of last update for this object
  55         // There is a problem with "updated" during deserialization because of the @Version annotation.
  56         @XmlTransient
  57         //@XmlElement(name ="Updated")
  58         private Calendar updated;
  59
  60         @XmlElement(name = "UpdatedBy")
  61         private Person updatedBy;
  62
  63         @XmlElement(name = "NextVersion")
  64         private T nextVersion;
  65
  66         @XmlElement(name = "PreviousVersion")
  67         private T previousVersion;
  68
  69
  70         /**
  71          * Returns the succeeding version of this object with the same UUID
  72          * @return next, i.e. succeeding version of this object
  73          */
  74         //@OneToOne(mappedBy="previousVersion")
  75         @Transient
  76         public T getNextVersion(){
  77                 return this.nextVersion;
  78         }
  79         public void setNextVersion(T nextVersion){
  80                 this.nextVersion = nextVersion;
  81         }
  82
  83         //@OneToOne
  84         @Transient
  85         public T getPreviousVersion(){
  86                 return this.previousVersion;
  87         }
  88         public void setPreviousVersion(T previousVersion){
  89                 this.previousVersion = previousVersion;
  90         }
  91
  92
  93         @ManyToOne(fetch=FetchType.LAZY)
  94         @Cascade({CascadeType.SAVE_UPDATE})
  95         public Person getUpdatedBy(){
  96                 return this.updatedBy;
  97         }
  98
  99         /**
 100          *
 101          * @param updatedBy    updatedBy
 102          */
 103         public void setUpdatedBy(Person updatedBy){
 104                 this.updatedBy = updatedBy;
 105         }
 106
 107         /**
 108          *
 109          * @return
 110          */
 111         @Temporal(TemporalType.TIMESTAMP)
 112         @Version
 113         @Basic(fetch = FetchType.LAZY)
 114         public Calendar getUpdated(){
 115                 return this.updated;
 116         }
 117
 118         /**
 119          *
 120          * @param updated    updated
 121          */
 122         public void setUpdated(Calendar updated){
 123                 this.updated = updated;
 124         }
 125
 126         /**
 127          * based on created
 128          */
 129         @Transient
 130         public Calendar getValidFrom(){
 131                 return null;
 132         }
 133
 134         /**
 135          * based on updated
 136          */
 137         @Transient
 138         public Calendar getValidTo(){
 139                 return null;
 140         }
 141
 142         /**
 143          * Is true if UUID and created timestamp are the same for the passed Object and this one.
 144          * @see eu.etaxonomy.cdm.model.common.CdmBase#equals(java.lang.Object)
 145          * See {@link http://www.hibernate.org/109.html hibernate109}, {@link http://www.geocities.com/technofundo/tech/java/equalhash.html geocities}
 146          * or {@link http://www.ibm.com/developerworks/java/library/j-jtp05273.html ibm}
 147          * for more information about equals and hashcode.
 148          */
 149         @Override
 150         public boolean equals(Object obj) {
 151                 if (obj == this){
 152                         return true;
 153                 }
 154                 if (obj == null){
 155                         return false;
 156                 }
 157                 if (!CdmBase.class.isAssignableFrom(obj.getClass())){
 158                         return false;
 159                 }
 160                 ICdmBase cdmObj = (ICdmBase)obj;
 161                 boolean uuidEqual = cdmObj.getUuid().equals(this.getUuid());
 162                 boolean createdEqual = cdmObj.getCreated().equals(this.getCreated());
 163                 if (! uuidEqual || !createdEqual){
 164                                 return false;
 165                 }
 166                 return true;
 167         }
 168
 169
 170         /** Overrides {@link eu.etaxonomy.cdm.model.common.CdmBase#hashCode()}
 171          *  See {@link http://www.hibernate.org/109.html}, {@link http://www.geocities.com/technofundo/tech/java/equalhash.html}
 172          * or {@link http://www.ibm.com/developerworks/java/library/j-jtp05273.html}
 173          * for more information about equals and hashcode.
 174          */
 175          @Override
 176         public int hashCode() {
 177                    int hashCode = 7;
 178                    hashCode = 29 * hashCode + this.getUuid().hashCode();
 179                    //hashCode = 29 * hashCode + this.getCreated().hashCode();
 180                    return hashCode;
 181         }
 182
 183 //********************** CLONE *****************************************/
 184
 185         /**
 186          * Clones this versionable entity.
 187          * Set fields for nextVersion, previousVersion, updated, updatedBy and createdBy are set to <tt>null</tt>
 188          * The id is set to 0.
 189          * The uuid is created new.
 190          * The createdWhen is set to the current date.
 191          * @see java.lang.Object#clone()
 192          */
 193         public Object clone() throws CloneNotSupportedException{
 194                 VersionableEntity result = (VersionableEntity)super.clone();
 195
 196                 //TODO ?
 197                 result.setNextVersion(null);
 198                 result.setPreviousVersion(null);
 199                 result.setUpdated(null);
 200                 result.setUpdatedBy(null);
 201
 202                 //no changes to: -
 203                 return result;
 204         }
 205 }