ChartBeansSystemListener.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 2006 - 2009 Pentaho Corporation.  All rights reserved.
 *
 *
 * Created Jun 26, 2009 
 * @author gmoran
 */
package org.pentaho.platform.plugin.action.chartbeans;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import org.dom4j.Element;
import org.pentaho.chart.ChartBeanFactory;
import org.pentaho.chart.plugin.IChartPlugin;
import org.pentaho.platform.api.engine.IPentahoSession;
import org.pentaho.platform.api.engine.IPentahoSystemListener;
import org.pentaho.platform.api.engine.IPluginManager;
import org.pentaho.platform.api.engine.PluginBeanException;
import org.pentaho.platform.engine.core.system.PentahoSystem;
import org.pentaho.platform.plugin.action.messages.Messages;
import org.pentaho.platform.util.logging.Logger;

public class ChartBeansSystemListener implements IPentahoSystemListener {

	private String configFile = "chartbeans/chartbeans_config.xml"; //$NON-NLS-1$

	public ChartBeansSystemListener() {
	}

	public boolean startup(final IPentahoSession session) {
		try {
			ChartBeanFactory.loadDefaultChartPlugins(initPlugins());
			List<Element> nodes = PentahoSystem.getSystemSettings().getSystemSettings(configFile, "max-data-points-per-chart"); //$NON-NLS-1$
			if (nodes.size() > 0) {
			  int maxDataPointsPerChart = Integer.parseInt(nodes.get(0).getText());
			  if (maxDataPointsPerChart > 0) {
			    ChartBeanFactory.setMaxDataPointsPerChart(maxDataPointsPerChart);
			  }
			}

		} catch (Exception ex) {
			Logger
					.warn(
							ChartBeansSystemListener.class.getName(),
							Messages.getInstance().getString("ChartBeansSystemListener.ERROR_0004_LOAD_FAILED"),  //$NON-NLS-1$
							ex);
			return false;
		}
		return true;
	}

	/**
	 * This methods looks in the chartbeans configuration file, and retrieves the 
	 * prescribed list of chart plugins (renderers). For each defined renderer, 
	 * the method then looks to the PluginManager to see if that renderer has 
	 * been overridden. If it has, then the class defined in the PluginManager 
	 * will be loaded IN PLACE OF the configuration file's class.  
	 * 
	 * @return list of available chart "plugin" (renderer) instances.
	 * @throws Exception if no chart plugins (renderers) are found.
	 */
	@SuppressWarnings("unchecked")
	private List <IChartPlugin> initPlugins() throws Exception {
		ArrayList<IChartPlugin> plugins = new ArrayList<IChartPlugin>();
		HashMap<String, Object> pluginMap = new HashMap<String, Object>();

		List<Element> nodes = PentahoSystem.getSystemSettings().getSystemSettings(configFile, "bean"); //$NON-NLS-1$

		if (nodes == null || nodes.size() == 0) {
			String msg = Messages.getInstance().getString("ChartBeansSystemListener.ERROR_0001_CONFIG_MISSING"); //$NON-NLS-1$
			Logger.warn(ChartBeansSystemListener.class.getName(), msg);
			throw new ChartSystemInitializationException(msg);
		}

		Element node;
		String id;
		Object plugin;
		IPluginManager pluginManager = PentahoSystem.get(IPluginManager.class);

		for (int i = 0; i < nodes.size(); i++) {
			node = nodes.get(i);
			id = node.attribute("id").getText(); //$NON-NLS-1$
			pluginMap.put(id, node.attribute("class").getText()); //$NON-NLS-1$

			// Now let's see if there is a plugin overriding this engine...
			if ((null != pluginManager) && (pluginManager.isBeanRegistered(id))) {
				try {
				  plugin = pluginManager.getBean(id);
					pluginMap.put(id, plugin);
				} catch (PluginBeanException e) {
					Logger.warn(ChartBeansSystemListener.class.getName(),
									Messages.getInstance().getString("ChartBeansSystemListener.ERROR_0002_PLUGINMANAGER_BEAN_MISSING", id),//$NON-NLS-1$
									e);
				}
			}
		}
		

		for (Object clazz : pluginMap.values()) {

			try {
			  if (clazz instanceof String){
	        plugins.add((IChartPlugin) Class.forName(clazz.toString()).newInstance());
			  }else{
			    plugins.add((IChartPlugin)clazz);
			  }
			} catch (Exception ex) {
				Logger.warn(ChartBeansSystemListener.class.getName(),
						Messages.getInstance().getString("ChartBeansSystemListener.ERROR_0003_CLASS_CREATION_PROBLEM") + clazz, ex); //$NON-NLS-1$
			}
		}
		return plugins;
	}

	public void setConfigFile(String configFile) {
		this.configFile = configFile;
	}

	public void shutdown() {
		// Nothing required
	}

}