EDIT

/**

* Copyright (C) 2018 EDIT

* European Distributed Institute of Taxonomy

* http://www.e-taxonomy.eu

*

* The contents of this file are subject to the Mozilla Public License Version 1.1

* See LICENSE.TXT at the top of this package for the full license terms.

*/

package eu.etaxonomy.cdm.model;

import java.io.Serializable;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import java.util.ArrayList;

import java.util.Collection;

import java.util.List;

import org.apache.commons.lang3.StringUtils;

import eu.etaxonomy.cdm.model.common.CdmBase;

/**

 * In many cases the add*() and remove*() methods of entity classes contain important business

 * logic which would be short-circuited if the set*() method would be public. This adapter allows

 * providing setter methods to make the bean property writable.

 * <p>

 * The {{@link #setCollection(CdmBase, Collection)} method uses the add*() and remove*() methods

 * in order to update the collection field of the bean.

 * <p>

 * Usage example:

 * <pre>

 *   public void setTeamMembers(List<Person> teamMembers) throws SetterAdapterException {

 *      new EntityCollectionSetterAdapter<Team, Person>(Team.class, Person.class, "teamMembers").setCollection(this, teamMembers);

 *   }

 * </pre>

 *

 * see https://dev.e-taxonomy.eu/redmine/issues/7600

 *

 * @author a.kohlbecker

 * @since Nov 15, 2018

 *

 */

public class EntityCollectionSetterAdapter<CDM extends CdmBase, T extends CdmBase> implements Serializable {

    private static final long serialVersionUID = 1L;

    private static final String GETTER_PREFIX = "get";

    private Class<T> propertyItemType;

    private Class<CDM> beanClass;

    private String propertyName;

    private String addMethodName;

    private String removMethodName;

    public EntityCollectionSetterAdapter(Class<CDM> beanClass, Class<T> propertyItemType, String propertyName){

        this(beanClass,

             propertyItemType,

             propertyName,

             "add" + StringUtils.capitalize(propertyName.substring(0, propertyName.length() - 1)),

             "remove" + StringUtils.capitalize(propertyName.substring(0, propertyName.length() - 1))

             );

    }

    public EntityCollectionSetterAdapter(Class<CDM> beanClass, Class<T> propertyItemType, String propertyName, String addMethodName, String removMethodName){

        this.beanClass = beanClass;

        this.propertyItemType = propertyItemType;

        this.propertyName = propertyName;

        this.addMethodName = addMethodName;

        this.removMethodName = removMethodName;

    }

    public void setCollection(CDM bean, Collection<T> items) throws SetterAdapterException {

        Method getterMethod = null;

        Method addMethod;

        Method removeMethod;

        try{

            getterMethod = beanClass.getDeclaredMethod(GETTER_PREFIX + StringUtils.capitalize(propertyName));

            addMethod = beanClass.getDeclaredMethod(addMethodName, propertyItemType);

            removeMethod = beanClass.getDeclaredMethod(removMethodName, propertyItemType);

            Collection<T> getterCollection = (Collection<T>) getterMethod.invoke(bean);

            List<T> currentItems = new ArrayList<>(getterCollection);

            List<T> itemsSeen = new ArrayList<>();

            for(T a : items){

                if(a == null){

                    continue;

                }

                if(!currentItems.contains(a)){

                    addMethod.invoke(bean, a);

                }

                itemsSeen.add(a);

            }

            for(T a : currentItems){

                if(!itemsSeen.contains(a)){

                    removeMethod.invoke(bean, a);

                }

        }

        } catch(ClassCastException e){

            throw new SetterAdapterException("getter return type (" + (getterMethod != null ? getterMethod.getReturnType() : "NULL") + ") incompatible with expected  property type " + propertyItemType, e);

        } catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {

            throw new SetterAdapterException("error invoking method", e);

        } catch (NoSuchMethodException | SecurityException e) {

            throw new SetterAdapterException("Property related method not found", e);

        }

    }

    public static class SetterAdapterException extends Exception {

        private static final long serialVersionUID = 1L;

        /**

         * @param message

         * @param cause

         */

        public SetterAdapterException(String message, Throwable cause) {

            super(message, cause);

        }

    }

}