QueryJasperDataSource.java

/*
** Module   : QueryJasperDataSource.java
** Abstract : Data source for a FWD Jasper report backed by a query.
**
** Copyright (c) 2018-2021, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------------Description---------------------------------------
** 001 SVL 20180207 Created initial version.
** 002 EVL 20210305 Adding ability to have data source without fields.
**     OM  20210309 Do not use DmoMeta as key in TableMapper because temp-tables might share the same
**                  DmoMeta instance.
**     SVL 20210809 Refactoring: moved getMatchingBufferField to DBUtils.
*/

/*
** 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 may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
**
** Additional terms under GNU Affero GPL version 3 section 7:
**
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**   terms apply to the works covered under the License.  These additional terms
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**
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**
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*/

package com.goldencode.p2j.reporting;

import com.goldencode.p2j.*;
import com.goldencode.p2j.persist.*;
import com.goldencode.p2j.ui.client.format.*;
import com.goldencode.p2j.util.*;
import java.util.*;
import net.sf.jasperreports.engine.*;

import static com.goldencode.p2j.reporting.ReportFactory.showError;

/**
 * Data source for a FWD Jasper report backed by a query.
 */
class QueryJasperDataSource
implements JasperDataSource
{
   /** Query for getting report data. */
   private final QueryWrapper query;

   /** Map of Jasper report field names to 4GL fields. */
   private HashMap<String, BufferField> fieldMapping;

   /**
    * <code>true</code> if the query was already iterated by this data source and we already got
    * the first record in the result set.
    */
   private boolean iterated = false;

   /**
    * Create data source which gets the report data from the specified query.
    *
    * @param query
    *        Query for getting report data.
    */
   QueryJasperDataSource(QueryWrapper query)
   {
      this.query = query;
   }

   /**
    * Tries to position the cursor on the next element in the data source.
    *
    * @return <code>true</code> if there is a next record, <code>false</code> otherwise.
    *
    * @throws JRException
    *         if any error occurs while trying to move to the next element.
    */
   @Override
   public boolean next()
   throws JRException
   {
      if (!iterated)
      {
         iterated = true;
         return query.getFirst().booleanValue();
      }
      else
      {
         return query.getNext().booleanValue();
      }
   }

   /**
    * Gets the field value for the current position.
    *
    * @param  field
    *         Field to get.
    *
    * @return an object containing the field value. The object type must be the field object type.
    *
    * @throws JRException
    *         if any error occurs while trying to get the field value.
    */
   @Override
   public Object getFieldValue(JRField field)
   throws JRException
   {
      BufferField progressField = fieldMapping.get(field.getName());
      BaseDataType progressValue = progressField.value();
      return JasperReportWrapper.getJavaValue(progressValue, field.getValueClass());
   }

   /**
    * Get compiled Jasper report for the given report design file.
    *
    * @param  designFileName
    *         File name of the Jasper report design file.
    *
    * @return compiled Jasper report for the given report design file.
    */
   @Override
   public JasperReport getReport(String designFileName)
   {
      return ReportFactory.getReport(designFileName);
   }

   /**
    * Executed before report is filled from the data source.
    *
    * @param  report
    *         Jasper report to be filled.
    *
    * @return <code>true</code> on success, <code>false</code> if the data source cannot provide
    *         data.
    */
   @Override
   public boolean reportStarted(JasperReport report)
   {
      if (!query.isOpen().booleanValue())
      {
         showError("Query should be open before the report is run.");
         return false;
      }

      return buildFieldMapping(report);
   }

   /**
    * Executed after report was filled from the data source.
    *
    * @param  error
    *         <code>true</code> if there were problems while getting data from the data source.
    *         <code>false</code> on success,
    */
   @Override
   public void reportFinished(boolean error)
   {
   }

   /**
    * Get underlying 4GL query object which provides data for the report.
    *
    * @return handle to the underlying 4GL query object which provides data for the report.
    */
   @Override
   public handle asProgressObject()
   {
      return new handle(query);
   }

   /**
    * Build and store field mapping (Jasper report field names to 4GL fields) for the given
    * report.
    *
    * @param  report
    *         Jasper report for which we need to build a field mapping.
    *
    * @return <code>true</code> on success.
    */
   private boolean buildFieldMapping(JasperReport report)
   {
      fieldMapping = new HashMap<>();
      JRField[] allFields = report.getFields();
      // check the possibility to have any fields, no fields can also be valid
      if (allFields != null && allFields.length > 0)
      {
         for (JRField jrField : allFields)
         {
            BufferField progressField = getMatchingBufferField(jrField);
            if (progressField == null)
            {
               // error was displayed by getMatchingBufferField
               return false;
            }

            // validate field data types
            try
            {
               BaseDataType progressBDT =
                     DisplayFormat.instanceOfType(progressField.getDataType().getValue());
               JasperReportWrapper.getJavaValue(progressBDT, jrField.getValueClass());
            }
            catch (IllegalArgumentException e)
            {
               showError("Invalid data type of report field " + jrField.getName(), e);
               return false;
            }

            fieldMapping.put(jrField.getName(), progressField);
         }
      }

      return true;
   }

   /**
    * Get the 4GL buffer field matching the given Jasper report field. Search is performed by
    * report field name which should have format "4gl-buffer-name.4gl-field-name" or
    * "4gl-field-name". If explicit buffer name is not specified and query has multiple buffers
    * which have the field with the specified name, error is raised.
    *
    * @param   reportField
    *          Jasper report field.
    *
    * @return  matching 4GL buffer field or <code>null</code> if there is no matching field.
    */
   private BufferField getMatchingBufferField(JRField reportField)
   {
      String fullName = reportField.getName();

      try
      {
         return DBUtils.getMatchingBufferField(query, fullName);
      }
      catch (NumberedException e)
      {
         switch (e.getNumber())
         {
            case 1:
               showError(String.format("There is no matching 4GL field for Jasper report field '%s'",
                     fullName));
               break;
            case 2:
               showError(String.format("There are multiple buffers with the field named '%s'. " +
                           "Specify buffer name explicitly using 'buffer-name.field-name' notation.",
                     fullName));
         }

         return null;
      }
   }
}