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package com.ricebridge.csvman;


import org.jostraca.util.Internal;
import org.jostraca.util.Standard;

import javax.swing.table.*;


/** An implementation of {@link LineProvider} that provides data lines for saving
 *  from a {@link javax.swing.table.TableModel}</a> object.
 *    <p>The easiest way to save your CSV data using this format is to use the
 *  {@link CsvManager#saveTableModel(Object,TableModel) CsvManager.saveTableModel} method.
 *  You can get a <code>TableModel</code> from a {@link javax.swing.JTable} using the 
 *  {@link javax.swing.JTable#getModel JTable.getModel} method.</p>
 *    <p><code>TableModelLineProvider</code> is designed to be subclassed. You can change
 *  the default implementation by calling the 
 *  {@link com.ricebridge.csvman.CsvManagerStore#setTableModelLineProviderClass CsvManagerStore.setTableModelLineProviderClass}
 *  method, and providing a subclass of 
 *  <code>TableModelLineProvider</code>. {@link CsvManagerStore} can be accessed 
 *  using {@link CsvManager#getCsvManagerStore}.</p>
 *    <p>The <b><a href="TableModelLineProvider.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 LineProvider
 *  @see CustomLineProvider
 *  @see BasicLineProvider 
 *  @see AsListsLineProvider 
 *  @see ResultSetLineProvider 
 *  @see BeanLineProvider 
 */
public class TableModelLineProvider extends CustomLineProvider {

  // static

  /** Save the {@link javax.swing.table.TableModel TableModel} column names as the first line of the CSV file.
   *  (name for {@link CsvSpec#setProperty CsvSpec.setProperty}: <code>TableModel.saveHeaders</code>). 
   */
  public static final String PROP_TableModel_saveHeaders = "TableModel.saveHeaders";

  /** Default value of <code>TableModel.saveHeaders</code> (<code>false</code>). */
  public static final boolean DEFAULT_TableModel_saveHeaders = false;




  // protected

  /** Save the column headers to the CSV file. */
  protected boolean iSaveHeaders = DEFAULT_TableModel_saveHeaders;

  /** The {@link javax.swing.table.TableModel} that the data comes from. */
  protected TableModel iTableModel  = null;

  /** The column headers */
  protected String[] iHeaders     = null;

  /** Flag to indicate processing of the first line. */
  protected boolean iFirstLine   = true;

  /** Number of data fields per line. */
  protected int iFieldCount  = 0;

  /** Current line. */
  protected long iLineIndex   = 0;



  // constructors
  
  /** Create uninitialised for use with {@link #setTableModel}. */
  public TableModelLineProvider() {
    // init with setTableModel
  }


  /** Create initialised. See {@link #setTableModel} for details. 
   *  @param pTableModel  <code>TableModel</code> providing data
   *  @param pSaveHeaders Save the <code>TableModel</code> headers as first line
   */
  public TableModelLineProvider( TableModel pTableModel, boolean pSaveHeaders ) {
    setTableModel( pTableModel, pSaveHeaders );
  }




  // CustomLineProvider methods

  /** Handle property settings for loading data from a {@link javax.swing.table.TableModel TableModel}. 
   *    <p>You can change these using {@link CsvSpec}.</p>
   *    <p>Compatibility note: the correct way to change the settings for a {@link LineProvider} 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>save</code> method parameters (for example: <code>pHasHeaders</code> 
   *  in {@link CsvManager#save(File,TableModel,boolean) CsvManager.save(File, TableModel, 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_TableModel_saveHeaders}.</p>
   *
   *  @see LineProvider#setCsvSpec
   *  @see #PROP_TableModel_saveHeaders
   */
  protected void setCsvSpecImpl( CsvSpec pCsvSpec ) throws Exception {
    iSaveHeaders = pCsvSpec.getBooleanProperty( PROP_TableModel_saveHeaders );
  }


  /** Start the saving process. 
   *  @see LineProvider#startProcess()
   */
  public void startProcessImpl() throws Exception {
    iFirstLine = true;
    iLineIndex = 0;
  }


  /** Return <code>true</code> if {@link javax.swing.table.TableModel TableModel} contains more rows. */
  public boolean hasNextLineImpl() throws Exception {
    boolean hasNextLine = false;
    if( iSaveHeaders && iFirstLine ) {
      hasNextLine = true;
    }
    else {
      hasNextLine = ( iLineIndex < iTableModel.getRowCount() );
    }

    return hasNextLine;
  }


  /** Return the current row of the {@link javax.swing.table.TableModel TableModel} as a <code>String[]</code> array. */
  public String[] nextLineImpl() throws Exception {
    String[] line = null;

    if( iSaveHeaders && iFirstLine ) {
      line = iHeaders;
      iFirstLine = false;
    }
    else {
      line = new String[iFieldCount];
      for( int fI = 0; fI < iFieldCount; fI++ ) {
        line[fI] = String.valueOf( iTableModel.getValueAt( (int) iLineIndex, fI ) );
      }
      iLineIndex++;
    }

    return line;
  }




  // public methods

  /** Set the {@link javax.swing.table.TableModel} providing data to save. 
   *    <p>The default number of fields per line is taken from 
   *  {@link javax.swing.table.TableModel#getColumnCount TableModel.getColumnCount}</a>
   *  and the headers (output as the first line when {@link #PROP_TableModel_saveHeaders} is <code>true)</code>, 
   *  are taken from {@link javax.swing.table.TableModel#getColumnName TableModel.getColumnName}.
   *  </p>
   *  @param pTableModel  <code>TableModel</code> providing data
   *  @param pSaveHeaders Save the <code>TableModel</code> headers as first line
   */
  public void setTableModel( TableModel pTableModel, boolean pSaveHeaders ) {
    iTableModel  = (TableModel) Internal.null_arg( pTableModel );
    iSaveHeaders = iSaveHeaders || pSaveHeaders;

    iFieldCount  = iTableModel.getColumnCount();
    if( iSaveHeaders && 0 < iFieldCount ) {
      iHeaders = new String[ iFieldCount ];
      for( int cI = 0; cI < iFieldCount; cI++ ) {
        iHeaders[cI] = iTableModel.getColumnName( cI );
      }
    }
    else {
      iSaveHeaders = false;
    }
  }


}