Java tutorial
/* This file is part of Subsonic. Subsonic 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. Subsonic 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 Subsonic. If not, see <http://www.gnu.org/licenses/>. Copyright 2009 (C) Sindre Mehus */ package net.sourceforge.subsonic.controller; import net.sourceforge.subsonic.domain.*; import net.sourceforge.subsonic.service.*; import org.jfree.chart.*; import org.jfree.chart.axis.*; import org.jfree.chart.plot.*; import org.jfree.chart.renderer.xy.*; import org.jfree.data.*; import org.jfree.data.time.*; import org.springframework.web.servlet.*; import javax.servlet.http.*; import java.awt.*; import java.util.*; import java.util.List; /** * Controller for generating a chart showing bitrate vs time. * * @author Sindre Mehus */ public class StatusChartController extends AbstractChartController { private StatusService statusService; public static final int IMAGE_WIDTH = 350; public static final int IMAGE_HEIGHT = 150; public synchronized ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception { String type = request.getParameter("type"); int index = Integer.parseInt(request.getParameter("index")); List<TransferStatus> statuses = Collections.emptyList(); if ("stream".equals(type)) { statuses = statusService.getAllStreamStatuses(); } else if ("download".equals(type)) { statuses = statusService.getAllDownloadStatuses(); } else if ("upload".equals(type)) { statuses = statusService.getAllUploadStatuses(); } if (index < 0 || index >= statuses.size()) { return null; } TransferStatus status = statuses.get(index); TimeSeries series = new TimeSeries("Kbps", Millisecond.class); TransferStatus.SampleHistory history = status.getHistory(); long to = System.currentTimeMillis(); long from = to - status.getHistoryLengthMillis(); Range range = new DateRange(from, to); if (!history.isEmpty()) { TransferStatus.Sample previous = history.get(0); for (int i = 1; i < history.size(); i++) { TransferStatus.Sample sample = history.get(i); long elapsedTimeMilis = sample.getTimestamp() - previous.getTimestamp(); long bytesStreamed = Math.max(0L, sample.getBytesTransfered() - previous.getBytesTransfered()); double kbps = (8.0 * bytesStreamed / 1024.0) / (elapsedTimeMilis / 1000.0); series.addOrUpdate(new Millisecond(new Date(sample.getTimestamp())), kbps); previous = sample; } } // Compute moving average. series = MovingAverage.createMovingAverage(series, "Kbps", 20000, 5000); // Find min and max values. double min = 100; double max = 250; for (Object obj : series.getItems()) { TimeSeriesDataItem item = (TimeSeriesDataItem) obj; double value = item.getValue().doubleValue(); if (item.getPeriod().getFirstMillisecond() > from) { min = Math.min(min, value); max = Math.max(max, value); } } // Add 10% to max value. max *= 1.1D; // Subtract 10% from min value. min *= 0.9D; TimeSeriesCollection dataset = new TimeSeriesCollection(); dataset.addSeries(series); JFreeChart chart = ChartFactory.createTimeSeriesChart(null, null, null, dataset, false, false, false); XYPlot plot = (XYPlot) chart.getPlot(); plot.setRangeAxisLocation(AxisLocation.BOTTOM_OR_RIGHT); Paint background = new GradientPaint(0, 0, Color.lightGray, 0, IMAGE_HEIGHT, Color.white); plot.setBackgroundPaint(background); XYItemRenderer renderer = plot.getRendererForDataset(dataset); renderer.setSeriesPaint(0, Color.blue.darker()); renderer.setSeriesStroke(0, new BasicStroke(2f)); // Set theme-specific colors. Color bgColor = getBackground(request); Color fgColor = getForeground(request); chart.setBackgroundPaint(bgColor); ValueAxis domainAxis = plot.getDomainAxis(); domainAxis.setRange(range); domainAxis.setTickLabelPaint(fgColor); domainAxis.setTickMarkPaint(fgColor); domainAxis.setAxisLinePaint(fgColor); ValueAxis rangeAxis = plot.getRangeAxis(); rangeAxis.setRange(new Range(min, max)); rangeAxis.setTickLabelPaint(fgColor); rangeAxis.setTickMarkPaint(fgColor); rangeAxis.setAxisLinePaint(fgColor); ChartUtilities.writeChartAsPNG(response.getOutputStream(), chart, IMAGE_WIDTH, IMAGE_HEIGHT); return null; } public void setStatusService(StatusService statusService) { this.statusService = statusService; } }