Author: markt
Date: Thu Aug 29 23:40:35 2013
New Revision: 1518856
URL: http://svn.apache.org/r1518856
Log:
Add a trivial non-blocking (mainly read) example.
The primary purpose is to support the development of the non-blocking API with
the AJP connector.
Added:
tomcat/trunk/webapps/examples/WEB-INF/classes/nonblocking/
tomcat/trunk/webapps/examples/WEB-INF/classes/nonblocking/ByteCounter.java
(with props)
tomcat/trunk/webapps/examples/servlets/nonblocking/
tomcat/trunk/webapps/examples/servlets/nonblocking/bytecounter.html (with
props)
Modified:
tomcat/trunk/webapps/examples/WEB-INF/web.xml
tomcat/trunk/webapps/examples/servlets/index.html
Added:
tomcat/trunk/webapps/examples/WEB-INF/classes/nonblocking/ByteCounter.java
URL:
http://svn.apache.org/viewvc/tomcat/trunk/webapps/examples/WEB-INF/classes/nonblocking/ByteCounter.java?rev=1518856&view=auto
==============================================================================
--- tomcat/trunk/webapps/examples/WEB-INF/classes/nonblocking/ByteCounter.java
(added)
+++ tomcat/trunk/webapps/examples/WEB-INF/classes/nonblocking/ByteCounter.java
Thu Aug 29 23:40:35 2013
@@ -0,0 +1,142 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package nonblocking;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+
+import javax.servlet.AsyncContext;
+import javax.servlet.ReadListener;
+import javax.servlet.ServletException;
+import javax.servlet.ServletInputStream;
+import javax.servlet.ServletOutputStream;
+import javax.servlet.WriteListener;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+/**
+ * This doesn't do anything particularly useful - it just counts the total
+ * number of bytes in a request body while demonstrating how to perform
+ * non-blocking reads.
+ */
+public class ByteCounter extends HttpServlet {
+
+ private static final long serialVersionUID = 1L;
+
+ @Override
+ protected void doGet(HttpServletRequest req, HttpServletResponse resp)
+ throws ServletException, IOException {
+
+ resp.setContentType("text/plain");
+ resp.setCharacterEncoding("UTF-8");
+
+ resp.getWriter().println("Try again using a POST request.");
+ }
+
+ @Override
+ protected void doPost(HttpServletRequest req, HttpServletResponse resp)
+ throws ServletException, IOException {
+
+ resp.setContentType("text/plain");
+ resp.setCharacterEncoding("UTF-8");
+
+ // Non-blocking IO requires async
+ AsyncContext ac = req.startAsync();
+
+ // Use a single listener for read and write. Listeners often need to
+ // share state to coordinate reads and writes and this is much easier
as
+ // a single object.
+ @SuppressWarnings("unused")
+ CounterListener listener = new CounterListener(
+ ac, req.getInputStream(), resp.getOutputStream());
+ }
+
+
+ /**
+ * Keep in mind that each call may well be on a different thread to the
+ * previous call. Ensure that changes in values will be visible across
+ * threads. There should only ever be one container thread at a time
calling
+ * the listener.
+ */
+ private static class CounterListener implements ReadListener,
WriteListener {
+
+ private final AsyncContext ac;
+ private final ServletInputStream sis;
+ private final ServletOutputStream sos;
+
+ private volatile boolean readFinished = false;
+ private volatile long totalBytesRead = 0;
+ private byte[] buffer = new byte[8192];
+
+ private CounterListener(AsyncContext ac, ServletInputStream sis,
+ ServletOutputStream sos) {
+ this.ac = ac;
+ this.sis = sis;
+ this.sos = sos;
+
+ // In Tomcat, the order the listeners are set controls the order
+ // that the first calls are made. In this case, the write listener
+ // will be called before the write listener.
+ sis.setReadListener(this);
+ sos.setWriteListener(this);
+ }
+
+ @Override
+ public void onDataAvailable() throws IOException {
+ int read = 0;
+ // Loop as long as there is data to read. If isReady() returns
false
+ // the socket will be added to the poller and onDataAvailable()
will
+ // be called again as soon as there is more data to read.
+ while (sis.isReady() && read > -1) {
+ read = sis.read(buffer);
+ if (read > 0) {
+ totalBytesRead += read;
+ }
+ }
+ }
+
+ @Override
+ public void onAllDataRead() throws IOException {
+ readFinished = true;
+
+ // If sos is not ready to write data, the call to isReady() will
+ // register the socket with the poller which will trigger a call to
+ // onWritePossible() when the socket is ready to have data written
+ // to it.
+ if (sos.isReady()) {
+ onWritePossible();
+ }
+ }
+
+ @Override
+ public void onWritePossible() throws IOException {
+ if (readFinished) {
+ // Must be ready to write data if onWritePossible was called
+ String msg = "Total bytes written = [" + totalBytesRead + "]";
+ sos.write(msg.getBytes(StandardCharsets.UTF_8));
+ ac.complete();
+ }
+ }
+
+ @Override
+ public void onError(Throwable throwable) {
+ // Should probably log the throwable
+ ac.complete();
+ }
+ }
+}
Propchange:
tomcat/trunk/webapps/examples/WEB-INF/classes/nonblocking/ByteCounter.java
------------------------------------------------------------------------------
svn:eol-style = native
Modified: tomcat/trunk/webapps/examples/WEB-INF/web.xml
URL:
http://svn.apache.org/viewvc/tomcat/trunk/webapps/examples/WEB-INF/web.xml?rev=1518856&r1=1518855&r2=1518856&view=diff
==============================================================================
--- tomcat/trunk/webapps/examples/WEB-INF/web.xml (original)
+++ tomcat/trunk/webapps/examples/WEB-INF/web.xml Thu Aug 29 23:40:35 2013
@@ -367,4 +367,15 @@
<url-pattern>/async/stockticker</url-pattern>
</servlet-mapping>
+ <!-- Non-blocking IO examples -->
+ <servlet>
+ <servlet-class>nonblocking.ByteCounter</servlet-class>
+ <servlet-name>bytecounter</servlet-name>
+ <async-supported>true</async-supported>
+ </servlet>
+ <servlet-mapping>
+ <servlet-name>bytecounter</servlet-name>
+ <url-pattern>/servlets/nonblocking/bytecounter</url-pattern>
+ </servlet-mapping>
+
</web-app>
Modified: tomcat/trunk/webapps/examples/servlets/index.html
URL:
http://svn.apache.org/viewvc/tomcat/trunk/webapps/examples/servlets/index.html?rev=1518856&r1=1518855&r2=1518856&view=diff
==============================================================================
--- tomcat/trunk/webapps/examples/servlets/index.html (original)
+++ tomcat/trunk/webapps/examples/servlets/index.html Thu Aug 29 23:40:35 2013
@@ -178,9 +178,9 @@ for clarity.</p>
<td colspan="3">Servlet 3.1 Non-blocking IO examples</td>
</tr>
<tr VALIGN=TOP>
- <td>Checksum calculator </td>
+ <td>Byte counter </td>
<td VALIGN=TOP WIDTH="30%">
- <a href="../nonblocking/checksum"><img SRC="images/execute.gif" HSPACE=4
BORDER=0 align=TOP> Execute</a>
+ <a href="nonblocking/bytecounter.html"><img SRC="images/execute.gif"
HSPACE=4 BORDER=0 align=TOP> Execute</a>
</td>
<td WIDTH="30%"></td>
</tr>
Added: tomcat/trunk/webapps/examples/servlets/nonblocking/bytecounter.html
URL:
http://svn.apache.org/viewvc/tomcat/trunk/webapps/examples/servlets/nonblocking/bytecounter.html?rev=1518856&view=auto
==============================================================================
--- tomcat/trunk/webapps/examples/servlets/nonblocking/bytecounter.html (added)
+++ tomcat/trunk/webapps/examples/servlets/nonblocking/bytecounter.html Thu Aug
29 23:40:35 2013
@@ -0,0 +1,32 @@
+<!--
+ Licensed to the Apache Software Foundation (ASF) under one or more
+ contributor license agreements. See the NOTICE file distributed with
+ this work for additional information regarding copyright ownership.
+ The ASF licenses this file to You under the Apache License, Version 2.0
+ (the "License"); you may not use this file except in compliance with
+ the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+-->
+<html>
+ <head>
+ <title>Servlet 3.1 non-blocking IO examples: Byte counter</title>
+ </head>
+ <body>
+ <h1>Byte counter</h1>
+ <p>Select a file and/or enter some data using the form below and then
submit
+ it. The server will read the request body using non-blocking IO and then
+ respond with the total length of the request body in bytes.</p>
+ <form method="POST" enctype="multipart/form-data" action="bytecounter" >
+ <p><textarea name="data" rows="5" cols="60" ></textarea></p>
+ <p><input name="source" type="file" /></p>
+ <p><input type="submit" value="Submit" /></p>
+ </form>
+ </body>
+</html>
\ No newline at end of file
Propchange: tomcat/trunk/webapps/examples/servlets/nonblocking/bytecounter.html
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svn:eol-style = native
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