www.pudn.com > jfreereport-0.8.3f.zip > FontChangeFunction.java

/** 
 * ======================================== 
 * JFreeReport : a free Java report library 
 * ======================================== 
 * 
 * Project Info:  http://www.jfree.org/jfreereport/index.html 
 * Project Lead:  Thomas Morgner; 
 * 
 * (C) Copyright 2000-2002, by Simba Management Limited and Contributors. 
 * 
 * This library is free software; you can redistribute it and/or modify it under the terms 
 * of the GNU Lesser General Public License as published by the Free Software Foundation; 
 * either version 2.1 of the License, or (at your option) any later version. 
 * 
 * This library 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. 
 * 
 * You should have received a copy of the GNU Lesser General Public License along with this 
 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, 
 * Boston, MA 02111-1307, USA. 
 * 
 * ----------------------- 
 * FontChangeFunction.java 
 * ----------------------- 
 * (C)opyright 2000-2002, by Simba Management Limited. 
 * 
 * $Id: FontChangeFunction.java,v 1.3.2.1 2003/08/24 14:18:07 taqua Exp $ 
 * 
 * Changes 
 * ------- 
 * 26-May-2002 : Initial version 
 * 05-Jun-2002 : Documentation 
 * 28-Aug-2002 : ChangeLog 
 */ 
package com.jrefinery.report.demo.helper; 
 
import java.awt.Font; 
import java.io.Serializable; 
 
import com.jrefinery.report.Element; 
import com.jrefinery.report.TextElement; 
import com.jrefinery.report.event.ReportEvent; 
import com.jrefinery.report.function.AbstractFunction; 
import com.jrefinery.report.function.FunctionInitializeException; 
import com.jrefinery.report.targets.FontDefinition; 
 
/** 
 * This is a function used in report4-demo. The function demonstrates how to alter an 
 * elements property during the report generation. The elements font is changed base on 
 * the data provided in the reports datasource. 
 * 
 
 * For every new item row in the report, the font for that row is changed to the fontname 
 * specified in the second column of the report data source. 
 * 
 
 * Parameters:
 
 * The function expects the name of a field in the item band in the parameter "element". 
 * This functions value will always be null. 
 * 
 * @author Thomas Morgner 
 */ 
public class FontChangeFunction extends AbstractFunction implements Serializable 
{ 
 
  /** 
   * DefaultConstructor. 
   */ 
  public FontChangeFunction() 
  { 
  } 
 
  /** 
   * Before an ItemBand is printed, the report generator will call itemsAdvanced 
   * for all functions in the function collection. This is the right place to alter 
   * the font of the element defined in the "element" property, so that every ItemBand 
   * has the font set, that is defined in the data model. 
   * 
   * @param event the report event. 
   */ 
  public void itemsAdvanced(final ReportEvent event) 
  { 
    // if this is a preparerun, nothing gets printed and so no font change is required. 
    if (event.getState().isPrepareRun()) 
    { 
      return; 
    } 
 
    // Try to get the name of the font to be set. 
    // If the name is null, return without an excpetion, just do nothing. 
    final String fontname = (String) event.getDataRow().get(1); 
    if (fontname == null) 
    { 
      return; 
    } 
 
    // Lookup the element by name. If there no element found, the getElement function 
    // returns null, so we have to check this case. 
    final Element e = event.getReport().getItemBand().getElement(getElement()); 
 
    // set the font if an element was found. 
    if (e != null && (e instanceof TextElement)) 
    { 
      final TextElement tx = (TextElement) e; 
      tx.getStyle().setFontDefinitionProperty( 
          new FontDefinition(new Font(fontname, Font.PLAIN, 10))); 
    } 
  } 
 
  /** 
   * Performs the functions initialisation. The initialisation will fail, if the 
   * function has no valid name or the required parameter "element" is missing. 
   * 
 
   * @see #setElement(java.lang.String) 
   * 
   * @throws FunctionInitializeException if the element name has not been specified. 
   */ 
  public void initialize() throws FunctionInitializeException 
  { 
    super.initialize(); 
    if (getProperty("element") == null) 
    { 
      throw new FunctionInitializeException("Element name must be specified"); 
    } 
  } 
 
  /** 
   * Defines the name of the text element that gets its font altered. If the element 
   * does not exist or is no text element, the function will do nothing. 
   * 
 
   * This functions property is reachable by using the key "element" on getProperty. 
   * 
   * @param name  the element name. 
   */ 
  public void setElement(final String name) 
  { 
    setProperty("element", name); 
  } 
 
  /** 
   * Returns the name of the element that should get the font set. Returns an empty string, 
   * if the property is not set. 
   * 
   * @return the element name. 
   */ 
  public String getElement() 
  { 
    return getProperty("element", ""); 
  } 
 
  /** 
   * Returns the value calculated by this function. As this function does not calculate values, 
   * this method does always return null. 
   * 
   * @return always null, as this function does not calculate something. 
   */ 
  public Object getValue() 
  { 
    return null; 
  } 
}