--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/flys-artifacts/src/main/java/org/dive4elements/river/artifacts/services/AbstractChartService.java	Thu Apr 25 12:06:39 2013 +0200
@@ -0,0 +1,162 @@
+package org.dive4elements.river.artifacts.services;
+
+import java.awt.Dimension;
+import java.awt.Transparency;
+import java.awt.image.BufferedImage;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+
+import javax.imageio.ImageIO;
+
+import org.apache.log4j.Logger;
+import org.jfree.chart.JFreeChart;
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+import org.w3c.dom.NodeList;
+
+import org.dive4elements.artifactdatabase.DefaultService;
+import org.dive4elements.artifacts.CallMeta;
+import org.dive4elements.artifacts.GlobalContext;
+import org.dive4elements.artifacts.Service;
+
+/** Serve chart. */
+public abstract class AbstractChartService extends DefaultService {
+
+    public static final int DEFAULT_WIDTH = 240;
+    public static final int DEFAULT_HEIGHT = 180;
+
+    public static final String DEFAULT_FORMAT = "png";
+
+    private static final Logger log = Logger
+        .getLogger(AbstractChartService.class);
+
+    // TODO: Load fancy image from resources.
+    public static final byte[] EMPTY = { (byte) 0x89, (byte) 0x50, (byte) 0x4e,
+        (byte) 0x47, (byte) 0x0d, (byte) 0x0a, (byte) 0x1a, (byte) 0x0a,
+        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x0d, (byte) 0x49,
+        (byte) 0x48, (byte) 0x44, (byte) 0x52, (byte) 0x00, (byte) 0x00,
+        (byte) 0x00, (byte) 0x01, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+        (byte) 0x01, (byte) 0x08, (byte) 0x00, (byte) 0x00, (byte) 0x00,
+        (byte) 0x00, (byte) 0x3a, (byte) 0x7e, (byte) 0x9b, (byte) 0x55,
+        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x01, (byte) 0x73,
+        (byte) 0x52, (byte) 0x47, (byte) 0x42, (byte) 0x00, (byte) 0xae,
+        (byte) 0xce, (byte) 0x1c, (byte) 0xe9, (byte) 0x00, (byte) 0x00,
+        (byte) 0x00, (byte) 0x09, (byte) 0x70, (byte) 0x48, (byte) 0x59,
+        (byte) 0x73, (byte) 0x00, (byte) 0x00, (byte) 0x0b, (byte) 0x13,
+        (byte) 0x00, (byte) 0x00, (byte) 0x0b, (byte) 0x13, (byte) 0x01,
+        (byte) 0x00, (byte) 0x9a, (byte) 0x9c, (byte) 0x18, (byte) 0x00,
+        (byte) 0x00, (byte) 0x00, (byte) 0x07, (byte) 0x74, (byte) 0x49,
+        (byte) 0x4d, (byte) 0x45, (byte) 0x07, (byte) 0xdc, (byte) 0x04,
+        (byte) 0x04, (byte) 0x10, (byte) 0x30, (byte) 0x15, (byte) 0x7d,
+        (byte) 0x77, (byte) 0x36, (byte) 0x0b, (byte) 0x00, (byte) 0x00,
+        (byte) 0x00, (byte) 0x08, (byte) 0x74, (byte) 0x45, (byte) 0x58,
+        (byte) 0x74, (byte) 0x43, (byte) 0x6f, (byte) 0x6d, (byte) 0x6d,
+        (byte) 0x65, (byte) 0x6e, (byte) 0x74, (byte) 0x00, (byte) 0xf6,
+        (byte) 0xcc, (byte) 0x96, (byte) 0xbf, (byte) 0x00, (byte) 0x00,
+        (byte) 0x00, (byte) 0x0a, (byte) 0x49, (byte) 0x44, (byte) 0x41,
+        (byte) 0x54, (byte) 0x08, (byte) 0xd7, (byte) 0x63, (byte) 0xf8,
+        (byte) 0x0f, (byte) 0x00, (byte) 0x01, (byte) 0x01, (byte) 0x01,
+        (byte) 0x00, (byte) 0x1b, (byte) 0xb6, (byte) 0xee, (byte) 0x56,
+        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x49,
+        (byte) 0x45, (byte) 0x4e, (byte) 0x44, (byte) 0xae, (byte) 0x42,
+        (byte) 0x60, (byte) 0x82 };
+
+    private static final Output empty() {
+        return new Output(EMPTY, "image/png");
+    }
+
+    protected abstract JFreeChart createChart(Document data,
+        GlobalContext globalContext, CallMeta callMeta);
+
+    protected void init() {
+    };
+
+    protected void finish() {
+    };
+
+    @Override
+    public Service.Output process(Document data, GlobalContext globalContext,
+        CallMeta callMeta) {
+        log.debug("process");
+
+        init();
+        try {
+            JFreeChart chart = createChart(data, globalContext, callMeta);
+
+            if (chart == null) {
+                return empty();
+            }
+
+            Dimension extent = getExtent(data);
+            String format = getFormat(data);
+
+            return encode(chart, extent, format);
+        }
+        finally {
+            finish();
+        }
+    }
+
+    protected static Output encode(JFreeChart chart, Dimension extent,
+        String format) {
+        BufferedImage image = chart.createBufferedImage(extent.width,
+            extent.height, Transparency.BITMASK, null);
+
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+
+        try {
+            ImageIO.write(image, format, out);
+        }
+        catch (IOException ioe) {
+            log.warn("writing image failed", ioe);
+            return empty();
+        }
+
+        return new Output(out.toByteArray(), "image/" + format);
+    }
+
+    protected static Dimension getExtent(Document input) {
+
+        int width = DEFAULT_WIDTH;
+        int height = DEFAULT_HEIGHT;
+
+        NodeList extents = input.getElementsByTagName("extent");
+
+        if (extents.getLength() > 0) {
+            Element element = (Element) extents.item(0);
+            String w = element.getAttribute("width");
+            String h = element.getAttribute("height");
+
+            try {
+                width = Math.max(1, Integer.parseInt(w));
+            }
+            catch (NumberFormatException nfe) {
+                log.warn("width '" + w + "' is not a valid.");
+            }
+
+            try {
+                height = Math.max(1, Integer.parseInt(h));
+            }
+            catch (NumberFormatException nfe) {
+                log.warn("height '" + h + "' is not a valid");
+            }
+        }
+
+        return new Dimension(width, height);
+    }
+
+    protected static String getFormat(Document input) {
+        String format = DEFAULT_FORMAT;
+
+        NodeList formats = input.getElementsByTagName("format");
+
+        if (formats.getLength() > 0) {
+            String type = ((Element) formats.item(0)).getAttribute("type");
+            if (type.length() > 0) {
+                format = type;
+            }
+        }
+
+        return format;
+    }
+}