DataGrid.java

/*
 * This program is free software; you can redistribute it and/or modify it under the 
 * terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software 
 * Foundation.
 *
 * You should have received a copy of the GNU Lesser General Public License along with this 
 * program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html 
 * or from the Free Software Foundation, Inc., 
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * 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 Lesser General Public License for more details.
 *
 * Copyright 2005 - 2008 Pentaho Corporation.  All rights reserved.
 *
 * @created Sep 23, 2005 
 * @author James Dixon
 */

package org.pentaho.platform.util.xml.dom4j;

import java.util.HashMap;

import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.pentaho.commons.connection.IPentahoMetaData;
import org.pentaho.commons.connection.IPentahoResultSet;
import org.pentaho.platform.util.messages.LocaleHelper;

public class DataGrid {

  public static final int STYLE_ROWS = 1;

  public static final int STYLE_TREE = 2;

  Document gridDocument;

  int documentStyle;

  public DataGrid(final int documentStyle) {
    this.documentStyle = documentStyle;
  }

  public Document getDataDocument() {
    return gridDocument;
  }

  public int getDocumentStyle() {
    return documentStyle;
  }

  public void populate(final IPentahoResultSet results) {

    switch (documentStyle) {
      case STYLE_ROWS:
        populateRowStyle(results);
    }

  }

  protected void populateRowStyle(final IPentahoResultSet results) {
    gridDocument = DocumentHelper.createDocument();
    gridDocument.setXMLEncoding(LocaleHelper.getSystemEncoding());
    Element root = gridDocument.addElement("datagrid"); //$NON-NLS-1$

    // add metadata about the headers
    Element metadataNode = root.addElement("metadata"); //$NON-NLS-1$
    HashMap<String,String> headerMap = new HashMap<String,String>();
    IPentahoMetaData metadata = results.getMetaData();
    // first process the column headers
    Object headers[][] = metadata.getColumnHeaders();
    addHeaderMetadata(headers, metadataNode, headerMap);

    // now process the rows in the data set
    Element rowsNode = root.addElement("data"); //$NON-NLS-1$
    Object row[] = results.next();

    while (row != null) {
      // create a new node tree for every row
      Element rowNode = rowsNode.addElement("row"); //$NON-NLS-1$
      Element currentNode = rowNode;
      String headerId;
      for (int columnNo = 0; columnNo < row.length; columnNo++) {
        // TODO make sure the nodes are encoded well
        Object columnHeader;
        for (int headerNo = 0; headerNo < headers.length; headerNo++) {
          columnHeader = headers[headerNo][columnNo];
          headerId = headerMap.get(columnHeader);
          currentNode = currentNode.addElement(headerId);
          if (headerNo < row.length) {
            currentNode.addElement("value").setText(row[headerNo].toString()); //$NON-NLS-1$
          }
          // TODO support formatters
          // currentNode.addElement( "formatted" ).setText( row[
          // headerNo ].toString() );
        }
      }
      row = results.next();
    }
    // System .out.println(gridDocument.asXML());
  }

  protected void addHeaderMetadata(final Object headers[][], final Element metadataNode, final HashMap<String,String> headerMap) {
    if (headers == null) {
      return;
    }
    // use a map to ensure we only add this information once
    HashMap<String,String> metadataMap = new HashMap<String,String>();
    for (Object[] element : headers) {
      for (int y = 0; y < element.length; y++) {
        Object header = element[y];
        if (header instanceof String) {
          String headerStr = (String) header;
          metadataMap.put(headerStr, headerStr);
          createMetadata(headerStr, metadataNode, headerMap);
        }
        // TODO suppport heavier metadata objects
        else {
          String headerStr = header.toString();
          metadataMap.put(headerStr, headerStr);
          createMetadata(headerStr, metadataNode, headerMap);
        }

      }
    }
  }

  protected void createMetadata(final String header, final Element metadataNode, final HashMap<String,String> headerMap) {
    Element node = metadataNode.addElement("header"); //$NON-NLS-1$
    String id = "header" + headerMap.keySet().size(); //$NON-NLS-1$
    node.addAttribute("id", id); //$NON-NLS-1$
    node.addElement("name").setText(header); //$NON-NLS-1$
    node.addAttribute("format", ""); //$NON-NLS-1$ //$NON-NLS-2$
    Element title = node.addElement("title"); //$NON-NLS-1$
    title.setText(header);
    headerMap.put(header, id);
  }

  // TODO support creating metadata nodes for other metadata types
}