cdmlib-model/src/main/java/eu/etaxonomy/cdm/model/EntityCollectionSetterAdapter.java

   1 /**
   2 * Copyright (C) 2018 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 package eu.etaxonomy.cdm.model;
  10
  11 import java.lang.reflect.InvocationTargetException;
  12 import java.lang.reflect.Method;
  13 import java.util.ArrayList;
  14 import java.util.Collection;
  15 import java.util.List;
  16
  17 import org.apache.commons.lang3.StringUtils;
  18
  19 import eu.etaxonomy.cdm.model.common.CdmBase;
  20
  21 /**
  22  * In many cases the add*() and remove*() methods of entity classes contain important business
  23  * logic which would be short-circuited if the set*() method would be public. This adapter allows
  24  * providing setter methods to make the bean property writable.
  25  * <p>
  26  * The {{@link #setCollection(CdmBase, Collection)} method uses the add*() and remove*() methods
  27  * in order to update the collection field of the bean.
  28  * <p>
  29  * Usage example:
  30  * <pre>
  31  *   &#64;Transient
  32  *   &#64;Transient
  33  *   private EntityCollectionSetterAdapter<Team, Person> teamMembersSetterAdapter = new EntityCollectionSetterAdapter<Team, Person>(Team.class, Person.class, "teamMembers");
  34  *
  35  *   public void setTeamMembers(List<Person> teamMembers) throws SetterAdapterException {
  36  *       teamMembersSetterAdapter.setCollection(this, teamMembers);
  37  *   }
  38  </pre>
  39  *
  40  * see https://dev.e-taxonomy.eu/redmine/issues/7600
  41  *
  42  * @author a.kohlbecker
  43  * @since Nov 15, 2018
  44  *
  45  */
  46 public class EntityCollectionSetterAdapter<CDM extends CdmBase, T extends CdmBase> {
  47
  48     private Class<T> propertyItemType;
  49     private Method getMethod;
  50     private Method addMethod;
  51     private Method removeMethod;
  52     private Exception getMethodException;
  53     private Exception addMethodException;
  54     private Exception removeMethodException;
  55
  56     public EntityCollectionSetterAdapter(Class<CDM> beanClass, Class<T> propertyItemType, String propertyName){
  57         this(beanClass,
  58              propertyItemType,
  59              propertyName,
  60              "add" + StringUtils.capitalize(propertyName.substring(0, propertyName.length() - 1)),
  61              "remove" + StringUtils.capitalize(propertyName.substring(0, propertyName.length() - 1))
  62              );
  63     }
  64
  65     public EntityCollectionSetterAdapter(Class<CDM> beanClass, Class<T> propertyItemType, String propertyName, String addMethodName, String removMethodName){
  66
  67         this.propertyItemType = propertyItemType;
  68         try {
  69             getMethod = beanClass.getDeclaredMethod("get" + StringUtils.capitalize(propertyName));
  70         } catch (NoSuchMethodException | SecurityException e) {
  71             getMethodException = e;
  72         }
  73         try {
  74             addMethod = beanClass.getDeclaredMethod(addMethodName, propertyItemType);
  75         } catch (NoSuchMethodException | SecurityException e) {
  76             addMethodException = e;
  77         }
  78         try {
  79             removeMethod = beanClass.getDeclaredMethod(removMethodName, propertyItemType);
  80         } catch (NoSuchMethodException | SecurityException e) {
  81             removeMethodException = e;
  82         }
  83     }
  84
  85     public void setCollection(CDM bean, Collection<T> items) throws SetterAdapterException {
  86
  87         if(getMethodException != null){
  88             throw new SetterAdapterException("No getter method due to previous exception.", getMethodException);
  89         }
  90         if(addMethodException != null){
  91             throw new SetterAdapterException("No add method due to previous exception.", addMethodException);
  92         }
  93         if(removeMethodException != null){
  94             throw new SetterAdapterException("No remove method due to previous exception.", removeMethodException);
  95         }
  96
  97         try{
  98             Collection<T> getterCollection = (Collection<T>) getMethod.invoke(bean);
  99             List<T> currentItems = new ArrayList<>(getterCollection);
 100             List<T> itemsSeen = new ArrayList<>();
 101             for(T a : items){
 102                 if(a == null){
 103                     continue;
 104                 }
 105                 if(!currentItems.contains(a)){
 106                     addMethod.invoke(bean, a);
 107                 }
 108                 itemsSeen.add(a);
 109             }
 110             for(T a : currentItems){
 111                 if(!itemsSeen.contains(a)){
 112                     removeMethod.invoke(bean, a);
 113                 }
 114         }
 115         } catch(ClassCastException e){
 116             throw new SetterAdapterException("getter return type (" + getMethod.getReturnType() + ") incompatible with expected  property type " + propertyItemType, e);
 117         } catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
 118             throw new SetterAdapterException("error invoking method", e);
 119         }
 120     }
 121
 122     public static class SetterAdapterException extends Exception {
 123
 124         private static final long serialVersionUID = 1L;
 125
 126         /**
 127          * @param message
 128          * @param cause
 129          */
 130         public SetterAdapterException(String message, Throwable cause) {
 131             super(message, cause);
 132         }
 133
 134
 135
 136     }
 137
 138 }