net.sf.jstuff.integration.persistence.spring.BeanRowMapper Maven / Gradle / Ivy

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/*
 * Copyright 2010-2022 by Sebastian Thomschke and contributors.
 * SPDX-License-Identifier: EPL-2.0
 */
package net.sf.jstuff.integration.persistence.spring;

import static net.sf.jstuff.core.validation.NullAnalysisHelper.*;

import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.WeakHashMap;

import org.apache.commons.beanutils.BeanUtilsBean;
import org.apache.commons.beanutils.ConvertUtilsBean;
import org.apache.commons.beanutils.DynaProperty;
import org.apache.commons.beanutils.ResultSetDynaClass;
import org.apache.commons.beanutils.converters.DateConverter;
import org.springframework.jdbc.core.RowMapper;

import net.sf.jstuff.core.logging.Logger;
import net.sf.jstuff.core.validation.Args;

/**
 * Class represent a mapper that map column values of rows to bean properties
 * This implementation use schema: columnname(lowercase) --> bean property name
 *
 * @author Sebastian Thomschke
 */
public class BeanRowMapper implements RowMapper {
   private static final Logger LOG = Logger.create();

   private static final BeanUtilsBean BUB;

   static {
      /*
       * to avoid
       * org.apache.commons.beanutils.ConversionException: No value specified for 'Date'
       * at org.apache.commons.beanutils.converters.AbstractConverter.handleMissing(AbstractConverter.java:325)
       * at org.apache.commons.beanutils.converters.AbstractConverter.convert(AbstractConverter.java:151)
       * at org.apache.commons.beanutils.converters.ConverterFacade.convert(ConverterFacade.java:60)
       * at org.apache.commons.beanutils.BeanUtilsBean.convert(BeanUtilsBean.java:1079)
       * at org.apache.commons.beanutils.BeanUtilsBean.copyProperty(BeanUtilsBean.java:437)
       * at org.apache.commons.beanutils.BeanUtils.copyProperty(BeanUtils.java:160)
       */
      final ConvertUtilsBean converter = new ConvertUtilsBean();
      converter.register(new DateConverter(null), Date.class);
      BUB = new BeanUtilsBean(converter);
   }

   private Class beanClass = lazyNonNull();

   /**
    * propertyNameLowerCase => propertyName
    */
   private Map beanPropertyNames = lazyNonNull();

   private final WeakHashMap rsDynaClassesCache = new WeakHashMap<>();

   public BeanRowMapper(final Class beanClass) throws IntrospectionException {
      Args.notNull("beanClass", beanClass);

      setBeanClass(beanClass);
   }

   public Class getBeanClass() {
      return beanClass;
   }

   @Override
   public T mapRow(final ResultSet rs, final int rowNum) throws SQLException {
      ResultSetDynaClass rsDynaClass = rsDynaClassesCache.get(rs);
      if (rsDynaClass == null) {
         rsDynaClass = new ResultSetDynaClass(rs, true);
         rsDynaClassesCache.put(rs, rsDynaClass);
      }

      try {
         // generate bean instance
         final T bean = this.getBeanClass().getDeclaredConstructor().newInstance();
         //copy property from result set to created bean
         for (final DynaProperty dynaProp : rsDynaClass.getDynaProperties()) {
            final String dynaPropName = dynaProp.getName();
            final Object dynaPropValue = rsDynaClass.getObjectFromResultSet(dynaPropName);
            final String beanPropName = beanPropertyNames.get(dynaPropName);
            BUB.copyProperty(bean, beanPropName, dynaPropValue);
         }

         return bean;
      } catch (final SQLException | RuntimeException ex) {
         throw ex;
      } catch (final Exception ex) {
         LOG.error(ex);
         throw new SQLException(ex.getMessage());
      }
   }

   /**
    * Method set beanClass and read information from the bean and to create internal mapping table
    * for properties ( propertyNameLowerCase => propertyName )
    */
   protected void setBeanClass(final Class beanClass) throws IntrospectionException {
      // get beanInformation from bean e.g. property names
      final BeanInfo beanInfo = Introspector.getBeanInfo(beanClass);

      final var propsLowerCase = new HashMap();
      for (final PropertyDescriptor prop : beanInfo.getPropertyDescriptors()) {
         final String propName = prop.getName();
         if (propsLowerCase.put(propName.toLowerCase(), propName) != null)
            throw new IllegalStateException("Bean Class " + beanClass.getName()
               + " contains multiple properties with same lowercase representation: " + propName);
      }

      this.beanClass = beanClass;
      this.beanPropertyNames = propsLowerCase;
   }
}