Revision: 369
Author: tfenne
Date: 2006-08-10 17:10:58 -0700 (Thu, 10 Aug 2006)
ViewCVS: http://svn.sourceforge.net/stripes/?rev=369&view=rev
Log Message:
-----------
Fix for STS-237: Make StreamingResolution easier to subclass
Modified Paths:
--------------
trunk/stripes/src/net/sourceforge/stripes/action/StreamingResolution.java
Modified:
trunk/stripes/src/net/sourceforge/stripes/action/StreamingResolution.java
===================================================================
--- trunk/stripes/src/net/sourceforge/stripes/action/StreamingResolution.java
2006-08-10 22:58:08 UTC (rev 368)
+++ trunk/stripes/src/net/sourceforge/stripes/action/StreamingResolution.java
2006-08-11 00:10:58 UTC (rev 369)
@@ -14,25 +14,42 @@
*/
package net.sourceforge.stripes.action;
+import net.sourceforge.stripes.exception.StripesRuntimeException;
+
+import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
-import javax.servlet.ServletOutputStream;
+import java.io.IOException;
import java.io.InputStream;
+import java.io.PrintWriter;
import java.io.Reader;
-import java.io.PrintWriter;
-import java.io.IOException;
import java.io.StringReader;
/**
* <p>Resolution for streaming data back to the client (in place of forwarding
the user to
* another page). Designed to be used for streaming non-page data such as
generated images/charts
- * and XML islands.<p>
+ * and XML islands.</p>
*
* <p>Optionally supports the use of a file name which, if set, will cause a
* Content-Disposition header to be written to the output, resulting in a
"Save As" type
* dialog box appearing in the user's browser. If you do not wish to supply a
file name, but
- * wish to acheive this behaviour, simple supply a file name of "".<p>
+ * wish to acheive this behaviour, simple supply a file name of "".</p>
*
+ * <p>StreamingResolution is designed to be subclassed where necessary to
provide streaming
+ * output where the data being streamed is not contained in an InputStream or
Reader. This
+ * would normally be done using an anonymous inner class as follows:</p>
+ *
+ *<pre>
+ *return new StreamingResolution("text/xml") {
+ * public void stream(HttpServletResponse response) throws Exception {
+ * // custom output generation code
+ * response.getWriter.write(...);
+ * // or
+ * reponse.getOutputStream.write(...);
+ * }
+ *}.setFilename("your-filename.xml");
+ *</pre>
+ *
* @author Tim Fennell
*/
public class StreamingResolution implements Resolution {
@@ -43,6 +60,17 @@
private String characterEncoding;
/**
+ * Constructor only to be used when subclassing the StreamingResolution
(usually using
+ * an anonymous inner class. If this constructor is used, and stream() is
not overridden
+ * then an exception will be thrown!
+ *
+ * @param contentType the content type of the data in the stream (e.g.
image/png)
+ */
+ public StreamingResolution(String contentType) {
+ this.contentType = contentType;
+ }
+
+ /**
* Constructor that builds a StreamingResolution that will stream binary
data back to the
* client and identify the data as being of the specified content type.
*
@@ -112,7 +140,7 @@
* @throws IOException if there is a problem accessing one of the streams
or reader/writer
* objects used.
*/
- public void execute(HttpServletRequest request, HttpServletResponse
response) throws Exception {
+ final public void execute(HttpServletRequest request, HttpServletResponse
response) throws Exception {
response.setContentType(this.contentType);
if (this.characterEncoding != null)
response.setCharacterEncoding(characterEncoding);
@@ -121,8 +149,21 @@
response.setHeader("Content-disposition", "attachment; filename="
+ this.filename);
}
+ stream(response);
+ }
+
+ /**
+ * Responsible for the actual streaming of data through the response. If
subclassed,
+ * this method should be overridden to stream back data other than data
supplied by
+ * an InputStream or Reader supplied to a constructor.
+ *
+ * @param response the HttpServletResponse from which either the output
stream or writer
+ * can be obtained
+ * @throws IOException if any problems arise when streaming data
+ */
+ protected void stream(HttpServletResponse response) throws Exception {
int length = 0;
- if (reader != null) {
+ if (this.reader != null) {
char[] buffer = new char[512];
PrintWriter out = response.getWriter();
@@ -131,7 +172,7 @@
}
this.reader.close();
}
- else {
+ else if (this.inputStream != null) {
byte[] buffer = new byte[512];
ServletOutputStream out = response.getOutputStream();
@@ -141,5 +182,11 @@
this.inputStream.close();
}
+ else {
+ throw new StripesRuntimeException("A StreamingResolution was
constructed without " +
+ "supplying a Reader or InputStream, but stream() was not
overridden. Please " +
+ "either supply a source of streaming data, or override the
stream() method.");
+ }
}
+
}
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