com.userweave.presentation.model.EntityBaseLoadableDetachableModel.java Source code

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Here is the source code for com.userweave.presentation.model.EntityBaseLoadableDetachableModel.java

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/*******************************************************************************
 * This file is part of UserWeave.
 *
 *     UserWeave is free software: you can redistribute it and/or modify
 *     it under the terms of the GNU Affero General Public License as published by
 *     the Free Software Foundation, either version 3 of the License, or
 *     (at your option) any later version.
 *
 *     UserWeave is distributed in the hope that it will be useful,
 *     but WITHOUT ANY WARRANTY; without even the implied warranty of
 *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *     GNU Affero General Public License for more details.
 *
 *     You should have received a copy of the GNU Affero General Public License
 *     along with UserWeave.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Copyright 2012 User Prompt GmbH | Psychologic IT Expertise
 *******************************************************************************/
package com.userweave.presentation.model;

import java.io.Serializable;

import org.apache.wicket.injection.Injector;
import org.apache.wicket.model.LoadableDetachableModel;
import org.apache.wicket.spring.injection.annot.SpringBean;
import org.hibernate.proxy.HibernateProxy;

import com.userweave.dao.GeneralDao;
import com.userweave.domain.EntityBase;

@SuppressWarnings("serial")
public class EntityBaseLoadableDetachableModel<T extends EntityBase> extends LoadableDetachableModel {

    @SpringBean
    private GeneralDao generalDao;

    private T entity;
    private final Class<T> clazz;
    private Serializable id;

    /**
     * returns the stored entity if it is transient
     * 
     * loads the object from the database (if persistent)
     */
    @SuppressWarnings("unchecked")
    @Override
    protected T load() {
        if (generalDao == null) {
            Injector.get().inject(this);
        }

        if (entity != null) {
            if (entity.isTransient()) {
                // return the re
                return entity;
            } else {
                id = entity.getId();
                // remove reference to entity, we use the
                // persistent id now
                entity = null;
            }
        }

        // object comes from database 
        return (T) generalDao.load(clazz, id);
    }

    @SuppressWarnings("unchecked")
    @Override
    public T getObject() {
        return (T) super.getObject();
    }

    public EntityBaseLoadableDetachableModel(Class<T> clazz, Integer id) {
        this.clazz = clazz;
        this.id = id;

        if (id == null) {
            try {
                // here we dynamically create an instance
                // this *may* fail so we throw a runtime exception
                entity = clazz.newInstance();
            } catch (InstantiationException e) {
                throw new RuntimeException(e);
            } catch (IllegalAccessException e) {
                throw new RuntimeException(e);
            }
        }
    }

    @SuppressWarnings("unchecked")
    public EntityBaseLoadableDetachableModel(T entity) {
        super(entity);

        if (entity == null) {
            throw new NullPointerException();
        }

        if (entity.isTransient()) {
            // keep an object reference if entity is transient
            this.entity = entity;
        } else {
            this.id = entity.getId();
        }

        if (entity instanceof HibernateProxy) {
            HibernateProxy proxy = (HibernateProxy) entity;
            this.clazz = proxy.getHibernateLazyInitializer().getPersistentClass();
        } else {
            clazz = (Class<T>) entity.getClass();
        }
    }

}