OnDemandBeanCollection.java

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/*
 * Turró i Cutiller Foundation. License notice.
 * Copyright (C) 2011 Lluis Turró Cutiller <http://www.turro.org/>
 *
 * This program 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.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.turro.zkoss.print;
 
import java.util.Collection;
import net.sf.jasperreports.engine.JRException;
import net.sf.jasperreports.engine.JRField;
import net.sf.jasperreports.engine.data.JRBeanCollectionDataSource;
import org.zkoss.lang.Objects;
 
public abstract class OnDemandBeanCollection extends JRBeanCollectionDataSource {
 
  private Object realBean, previousBean;
  
  public OnDemandBeanCollection(Collection beanCollection, boolean isUseFieldDescription) {
    super(beanCollection, isUseFieldDescription);
  }
 
  public OnDemandBeanCollection(Collection beanCollection) {
    super(beanCollection);
  }
 
  @Override
  protected Object getFieldValue(Object bean, JRField field) throws JRException {
    if(!Objects.equals(bean, previousBean)) {
      previousBean = bean;
      realBean = getRealBean(bean);
    }
    return super.getFieldValue(realBean, field);
  }
 
  protected abstract Object getRealBean(Object bean);
  
}