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package com.ricebridge.csvman;


import org.jostraca.util.Internal;

import java.util.*;
import java.sql.*;


/** An implementation of {@link LineListener} that inserts loaded data lines 
 *  into a {@link java.sql.ResultSet ResultSet}</a>.
 *    <p>You can then use this <code>ResultSet</code> directly to retrieve the data. See {@link CsvResultSet}
 *  for more details. The easiest way to get a <code>ResultSet</code> of your CSV data is to use the
 *  {@link CsvManager#loadResultSet(Object) CsvManager.loadResultSet} method.</p>
 *    <p><code>ResultSetLineListener</code> is designed to be subclassed. You can change
 *  the default implementation by calling the 
 *  {@link CsvManagerStore#setResultSetLineListenerClass CsvManagerStore.setResultSetLineListenerClass}
 *  method, and providing a subclass of 
 *  <code>ResultSetLineListener</code>. {@link CsvManagerStore} can be accessed 
 *  using {@link CsvManager#getCsvManagerStore}.</p>
 *    <p>The <b><a href="ResultSetLineListener.java.html">Source Code</a></b> of this Java class 
 *    is available under a <a href="http://www.opensource.org/licenses/bsd-license.php">BSD-style license</a>.</p>
 *
 *  @see LineListener
 *  @see CustomLineListener
 *  @see BasicLineListener 
 *  @see AsListsLineListener 
 *  @see TableModelLineListener 
 *  @see BeanLineListener 
 */
public class ResultSetLineListener extends HeadersListenerSupport {

  // static

  /** Specify that the first row of data is a header line containing the names of the data fields.
   *  (name for {@link CsvSpec#setProperty CsvSpec.setProperty}: <code>ResultSet.dataHasHeaders</code>). 
   */
  public static final String PROP_ResultSet_dataHasHeaders = "ResultSet.dataHasHeaders";

  /** Default value of <code>ResultSet.dataHasHeaders</code> (<code>false</code>). */
  public static final boolean DEFAULT_ResultSet_dataHasHeaders = false;



  
  // protected
  
  /** <code>ResultSet</code> implementation class used to create new instances. */
  protected Class iCsvResultSetClass = CsvResultSet.class; 
  
  /** <code>List</code> of <code>String[]</code> arrays holding data lines. */
  protected ArrayList iData = new ArrayList();

  /** Number of data fields. */
  protected int iNumFields = 0;

  /** When <code>true</code>, the first line of CSV data should be a header line specifying the data field names. */
  protected boolean iDataHasHeaders = DEFAULT_ResultSet_dataHasHeaders;



  // CustomLineListener methods 

  /** Handle property settings for loading data in a {@link java.sql.ResultSet ResultSet}. 
   *    <p>You can change these using {@link CsvSpec}.</p>
   *    <p>Compatibility note: the correct way to change the settings for a {@link LineListener} is by using the
   *  {@link CsvSpec#setProperty CsvSpec.setProperty} method. <i>CSV Manager 1.1</i> also allowed you to set certain
   *  settings as <code>load</code> method parameters (for example: <code>pHasHeaders</code> 
   *  in {@link CsvManager#loadResultSet(File,boolean) CsvManager.loadResultSet(File, boolean)}. These parameters will
   *  be removed in <i>CSV Manager 2.0</i>, so you should not use them anymore. They are only retained for
   *  compatibility with <i>CSV Manager 1.1</i>.</p>
   *    <p>The property you can use here is: {@link #PROP_ResultSet_dataHasHeaders}.</p>
   *  @see LineListener#setCsvSpec
   *  @see #PROP_ResultSet_dataHasHeaders
   */
  protected void setCsvSpecImpl( CsvSpec pCsvSpec ) throws Exception {
    iNumFields      = pCsvSpec.getNumFields();
    iDataHasHeaders = pCsvSpec.getBooleanProperty( PROP_ResultSet_dataHasHeaders );
  }


  /** Start the loading process. 
   *  @see LineListener#startProcess()
   */
  protected void startProcessImpl() throws Exception {
    iData = new ArrayList();
  }

  
  /** Add the data line <code>String[]</code> array to the list of {@link java.sql.ResultSet} rows. */
  protected BadLine handleLineImpl( String[] pLine, int pNumFields, long pLineNumber, String pOriginalLine ) throws Exception {
    iData.add( pLine );
    return null; // always accept data line
  }


  /** End the loading process. 
   *  @see LineListener#endProcess()
   */ 
  protected void endProcessImpl() throws Exception {
    if( null == iData ) {
      iData = new ArrayList();
    }
  }


  // public methods

  /** Get a <code>ResultSet</code> instance that presents the CSV data. */
  public ResultSet getResultSet() {
    CsvResultSet csvrs = null;
    try {
      csvrs = (CsvResultSet) iCsvResultSetClass.newInstance();
    }
    catch( Exception e ) {
      throw new CsvManagerException( CsvManagerException.CODE_csvrs_new, 
                                     new String[] { "class", null==iCsvResultSetClass?"null":iCsvResultSetClass.getName() }, e );
    }

    // iHasHeaders defined in HeadersListenerSupport
    csvrs.setData( iData, iHasHeaders || iDataHasHeaders, iNumFields );
    return csvrs;
  }


  /** Use your own subclass of {@link CsvResultSet} for loading CSV data.
   *    <p>You may subclass <code>CsvResultSet</code> so that the CSV data is loaded into your own <code>ResultSet</code>. 
   *  You will need to provide an empty constructor so that the <code>newInstance</code> method will work. You
   *  must also provide, via this method, the class of your <code>ResultSet</code>. Do this like so:<pre>
   *    csvManager.getCsvManagerStore()
   *      .getResultSetLineListener().setCsvResultSetClass( MyCsvResultSet.class );
   *  </pre></p>
   *  <p>If subclassing does not fit with your requirements, consider implementing your own variation of
   *  {@link CsvResultSet} <a href="CsvResultSet.java.html">(source)</a> and 
   *  {@link ResultSetLineListener} <a href="ResultSetLineListener.java.html">(source)</a>
   *  based on the source code provided as part of this API documentation. </p>
   *    <p><b>NOTE:</b> this method is deprecated. To provide your own version of {@link CsvResultSet}, please
   *  subclass <code>ResultSetLineListener</code> directly and set the 
   *  {@link ResultSetLineListener#iCsvResultSetClass} member variable to your own 
   *  subclass of <code>CsvResultSet</code>.</p>
   *  @param pCsvResultSetClass class of <code>CsvResultSet</code> subclass
   *  @see   CsvResultSet
   */
  public void setCsvResultSetClass( Class pCsvResultSetClass ) {
    iCsvResultSetClass = (Class) Internal.null_arg( pCsvResultSetClass );
  }

}