org.pau.assetmanager.viewmodel.chart.ResourceImageGenerator.java Source code

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Here is the source code for org.pau.assetmanager.viewmodel.chart.ResourceImageGenerator.java

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/**
 * This file is part of Pau's Asset Manager Project.
 *
 * Pau's Asset Manager Project is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Pau's Asset Manager Project 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Pau's Asset Manager Project.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.pau.assetmanager.viewmodel.chart;

import java.io.File;
import java.io.FileOutputStream;
import java.util.Calendar;

import javax.servlet.ServletContext;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.jfree.chart.ChartUtilities;
import org.jfree.chart.JFreeChart;
import org.zkoss.zk.ui.Sessions;
import org.zkoss.zk.ui.util.Clients;

import com.google.common.base.Function;

/**
 * This class is a factory of Functions that can generate temporal
 * resources as files in a temp folder, that are cleaned (removed)
 * when they are more than one day old 
 * 
 * @author Pau Carr Cardona
 */
public class ResourceImageGenerator implements Function<JFreeChart, String> {

    static Logger logger = LogManager.getLogger(ResourceImageGenerator.class);

    protected ResourceImageGenerator() {
    }

    @Override
    public String apply(JFreeChart jfchart) {
        String tempFileName = "";
        try {
            ServletContext servletContext = Sessions.getCurrent().getWebApp().getServletContext();
            String tempDirPath = servletContext.getRealPath("") + File.separator + "TMP";
            File tempDir = new File(tempDirPath);
            if (!tempDir.exists()) {
                tempDir.mkdir();
            } else {
                cleanTempFolder(tempDir);
            }
            File tempFile = File.createTempFile("tmp", ".png", tempDir);
            tempFileName = tempFile.getName();
            FileOutputStream fileOutputStream = new FileOutputStream(tempFile);
            ChartUtilities.writeChartAsPNG(fileOutputStream, jfchart, 1200, 500);
        } catch (Throwable t) {
            logger.error("Error generating chart.", t);
        }
        Clients.clearBusy();
        return "TMP" + File.separator + tempFileName;
    }

    public static ResourceImageGenerator getFunction() {
        return new ResourceImageGenerator();
    }

    private static void cleanTempFolder(File directory) {
        Calendar cal = Calendar.getInstance();
        int daysBack = 1;
        cal.add(Calendar.DAY_OF_MONTH, daysBack * -1);
        long purgeTime = cal.getTimeInMillis();
        File[] files = directory.listFiles();
        for (File file : files) {
            if (file.lastModified() < purgeTime) {
                file.delete();
            }
        }
    }
}