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Made some minimal changes to improve the JFreeChart Result:

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- chart getter can be specified
- type (png/jpg) can be specified
- throws NPEs if required fields are missing
- added example configuration and Action

git-svn-id: https://svn.apache.org/repos/asf/struts/struts2/trunk@573912 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Philip Luppens
2007-09-08 21:48:46 +00:00
parent e2b0819538
commit 137da15d07
1 changed files with 131 additions and 54 deletions
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plugins/jfreechart/src/main/java/org/apache/struts2/dispatcher/ChartResult.java
+131 -54
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@@ -26,88 +26,165 @@ import com.opensymphony.xwork2.Result;
import org.jfree.chart.ChartUtilities;
import org.jfree.chart.JFreeChart;
import javax.servlet.http.HttpServletResponse;
import java.io.OutputStream;
/**
* <!-- START SNIPPET: description -->
* <p/>
* A custom Result type for chart data. Built on top of
* <a href="http://www.jfree.org/jfreechart/" target="_blank">JFreeChart</a>. When executed
* this Result will write the given chart as a PNG to the servlet output stream.
* this Result will write the given chart as a PNG or JPG to the servlet output stream.
* <p/>
* <!-- END SNIPPET: description -->
* <p/>
* <b>This result type takes the following parameters:</b>
* <p/>
* <!-- START SNIPPET: params -->
* <p/>
* <ul>
* <p/>
* <li><b>value</b> - the name of the JFreeChart object on the ValueStack, defaults to 'chart'.</li>
* <p/>
* <li><b>type</b> - the render type for this chart. Can be jpg (or jpeg) or png. Defaults to png.</li>
* <p/>
* <li><b>width (required)</b> - the width (in pixels) of the rendered chart.</li>
* <p/>
* <li><b>height (required)</b> - the height (in pixels) of the rendered chart.</li>
* <p/>
* </ul>
* <!-- END SNIPPET: params -->
* <p/>
* <b>Example:</b>
* <p/>
* <pre><!-- START SNIPPET: example -->
* public class ExampleChartAction extends ActionSupport {
*
* private JFreeChart chart;
*
* public String execute() throws Exception {
* // chart creation logic...
* XYSeries dataSeries = new XYSeries(new Integer(1)); // pass a key for this serie
* for (int i = 0; i <= 100; i++) {
* dataSeries.add(i, RandomUtils.nextInt());
* }
* XYSeriesCollection xyDataset = new XYSeriesCollection(dataSeries);
*
* ValueAxis xAxis = new NumberAxis("Raw Marks");
* ValueAxis yAxis = new NumberAxis("Moderated Marks");
*
* // set my chart variable
* chart =
* new JFreeChart( "Moderation Function", JFreeChart.DEFAULT_TITLE_FONT,
* new XYPlot( xyDataset, xAxis, yAxis, new StandardXYItemRenderer(StandardXYItemRenderer.LINES)),
* false);
* chart.setBackgroundPaint(java.awt.Color.white);
*
* return SUCCESS;
* }
*
* // this method will get called if we specify &lt;param name="value"&gt;chart&lt;/param&gt;
* public JFreeChart getChart() {
* return chart;
* }
* }
*
* &lt;result name="success" type="chart"&gt;
* &lt;param name="value"&gt;chart&lt;/param&gt;
* &lt;param name="type"&gt;png&lt;/param&gt;
* &lt;param name="width"&gt;640&lt;/param&gt;
* &lt;param name="height"&gt;480&lt;/param&gt;
* &lt;/result&gt;
* <!-- END SNIPPET: example --></pre>
*/
public class ChartResult implements Result {
private static final long serialVersionUID = -6484761870055986612L;
private static final String DEFAULT_TYPE = "png";
private static final String DEFAULT_VALUE = "chart";
JFreeChart chart;
boolean chartSet = false;
private int height;
private int width;
private JFreeChart chart; // the JFreeChart to render
Integer height, width;
String type = DEFAULT_TYPE; // supported are jpg, jpeg or png, defaults to png
String value = DEFAULT_VALUE; // defaults to 'chart'
// CONSTRUCTORS ----------------------------
public ChartResult() {
super();
}
public ChartResult(JFreeChart chart, int height, int width) {
setChart(chart);
this.height = height;
this.width = width;
}
/**
* Sets the JFreeChart to use.
*
* @param chart a JFreeChart object.
*/
public ChartResult setChart(JFreeChart chart) {
this.chart = chart;
chartSet = true;
return this;
}
/**
* Sets the chart height.
*
* @param height the height of the chart in pixels.
*/
public ChartResult setHeight(int height) {
this.height = height;
return this;
}
/**
* Sets the chart width.
*
* @param width the width of the chart in pixels.
*/
public ChartResult setWidth(int width) {
this.width = width;
return this;
}
// ACCESSORS ----------------------------
public Integer getHeight() {
return height;
}
public void setHeight(Integer height) {
this.height = height;
}
public Integer getWidth() {
return width;
}
public void setWidth(Integer width) {
this.width = width;
}
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
public String getValue() {
return value;
}
public void setValue(String value) {
this.value = value;
}
// OTHER METHODS -----------------------
// Required by com.opensymphony.xwork2.Result
/**
* Executes the result. Writes the given chart as a PNG to the servlet output stream.
* Executes the result. Writes the given chart as a PNG or JPG to the servlet output stream.
*
* @param invocation an encapsulation of the action execution state.
* @throws Exception if an error occurs when creating or writing the chart to the servlet output stream.
*/
public void execute(ActionInvocation invocation) throws Exception {
JFreeChart chart = null;
chart = (JFreeChart) invocation.getStack().findValue(value, JFreeChart.class);
if (chart == null) // we need to have a chart object - if not, blow up
throw new NullPointerException("No JFreeChart object found on the stack with name " + value);
// make sure we have some value for the width and height
if (height == null)
throw new NullPointerException("No height parameter was given.");
if (width == null)
throw new NullPointerException("No width parameter was given.");
if (chartSet) {
chart = this.chart;
} else {
chart = (JFreeChart) invocation.getStack().findValue("chart");
// get a reference to the servlet output stream to write our chart image to
OutputStream os = ServletActionContext.getResponse().getOutputStream();
try {
// check the type to see what kind of output we have to produce
if ("png".equalsIgnoreCase(type))
ChartUtilities.writeChartAsPNG(os, chart, width, height);
else if ("jpg".equalsIgnoreCase(type) || "jpeg".equalsIgnoreCase(type))
ChartUtilities.writeChartAsJPEG(os, chart, width, height);
else
throw new IllegalArgumentException(type + " is not a supported render type (only JPG and PNG are).");
} finally {
if (os != null) os.flush();
}
if (chart == null) {
throw new NullPointerException("No chart found");
}
HttpServletResponse response = ServletActionContext.getResponse();
OutputStream os = response.getOutputStream();
ChartUtilities.writeChartAsPNG(os, chart, width, height);
os.flush();
}
}
}