📄 browseradapter.java
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// Copyright (c) 2000 Just Objects B.V. <just@justobjects.nl>
// Distributable under LGPL license. See terms of license at gnu.org.
package nl.justobjects.pushlet.core;
import nl.justobjects.pushlet.util.Log;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Iterator;
/**
* Generic implementation of ClientAdapter for browser clients.
*
* @author Just van den Broecke - Just Objects ©
* @version $Id: BrowserAdapter.java,v 1.6 2007/11/09 13:15:35 justb Exp $
*/
public class BrowserAdapter implements ClientAdapter, Protocol {
public static final String START_DOCUMENT =
"<html><head><meta http-equiv=\"Pragma\" content=\"no-cache\"><meta http-equiv=\"Expires\" content=\"Tue, 31 Dec 1997 23:59:59 GMT\"></head>"
+ "<body>"
+ "\n<script language=\"JavaScript\"> var url=\" \"; \nfunction refresh() { document.location.href=url; }</script>";
public static final String END_DOCUMENT = "</body></html>";
private PrintWriter servletOut;
private HttpServletResponse servletRsp;
private int bytesSent;
/**
* Constructor.
*/
public BrowserAdapter(HttpServletResponse aServletResponse) {
servletRsp = aServletResponse;
}
/**
* Generic init.
*/
public void start() throws IOException {
// Keep servlet request/response objects until page ends in stop()
// Content type as HTML
servletRsp.setStatus(HttpServletResponse.SC_OK);
servletRsp.setContentType("text/html;charset=UTF-8");
// http://www.junlu.com/msg/45902.html
// Log.debug("bufsize=" + aRsp.getBufferSize());
servletOut = servletRsp.getWriter();
send(START_DOCUMENT);
}
/**
* Push Event to client.
*/
public void push(Event anEvent) throws IOException {
Log.debug("BCA event=" + anEvent.toXML());
// Check if we should refresh
if (anEvent.getEventType().equals(Protocol.E_REFRESH)) {
// Append refresh and tail of HTML document
// Construct the JS callback line to be sent as last line of doc.
// This will refresh the request using the unique id to determine
// the subscriber instance on the server. The client will wait for
// a number of milliseconds.
long refreshWaitMillis = Long.parseLong(anEvent.getField(P_WAIT));
// Create servlet request for requesting next events (refresh)
String url = anEvent.getField(P_URL);
String jsRefreshTrigger = "\n<script language=\"JavaScript\">url=\'" + url + "\';\n setTimeout(\"refresh()\", " + refreshWaitMillis + ");\n</script>";
send(jsRefreshTrigger + END_DOCUMENT);
} else {
send(event2JavaScript(anEvent));
}
}
/**
* End HTML page in client browser.
*/
public void stop() {
// To be garbage collected if adapter remains active
servletOut = null;
}
/**
* Send any string to browser.
*/
protected void send(String s) throws IOException {
// Send string to browser.
// Log.debug("Adapter: sending: " + s);
if (servletOut == null) {
throw new IOException("Client adapter was stopped");
}
servletOut.print(s);
servletOut.flush();
// Note: this doesn't seem to have effect
// in Tomcat 4/5 if the client already disconnected.
servletRsp.flushBuffer();
bytesSent += s.length();
Log.debug("bytesSent= " + bytesSent);
// Log.debug("BCA sent event: " + s);
}
/**
* Converts the Java Event to a JavaScript function call in browser page.
*/
protected String event2JavaScript(Event event) throws IOException {
// Convert the event to a comma-separated string.
String jsArgs = "";
for (Iterator iter = event.getFieldNames(); iter.hasNext();) {
String name = (String) iter.next();
String value = event.getField(name);
String nextArgument = (jsArgs.equals("") ? "" : ",") + "'" + name + "'" + ", \"" + value + "\"";
jsArgs += nextArgument;
}
// Construct and return the function call */
return "<script language=\"JavaScript\">parent.push(" + jsArgs + ");</script>";
}
}
/*
* $Log: BrowserAdapter.java,v $
* Revision 1.6 2007/11/09 13:15:35 justb
* add charset=UTF-8 in returned HTTP content types
*
* Revision 1.5 2006/05/15 11:52:53 justb
* updates mainly for AJAX client
*
* Revision 1.4 2006/05/06 00:10:11 justb
* various chgs but not too serious...
*
* Revision 1.3 2005/02/28 12:45:59 justb
* introduced Command class
*
* Revision 1.2 2005/02/21 11:50:44 justb
* ohase1 of refactoring Subscriber into Session/Controller/Subscriber
*
* Revision 1.1 2005/02/18 10:07:23 justb
* many renamings of classes (make names compact)
*
* Revision 1.12 2005/02/15 13:30:23 justb
* changes for Tomcat buffering (now working in tc4 and 5.0)
*
* Revision 1.11 2005/01/24 22:45:58 justb
* getting safari to work
*
* Revision 1.10 2005/01/18 16:46:27 justb
* buffer size setting ignored by tomcat workings
*
* Revision 1.9 2004/10/24 12:58:18 justb
* revised client and test classes for new protocol
*
* Revision 1.8 2004/09/20 22:01:38 justb
* more changes for new protocol
*
* Revision 1.7 2004/09/03 22:35:37 justb
* Almost complete rewrite, just checking in now
*
* Revision 1.6 2004/08/15 16:00:15 justb
* enhancements to pull mode
*
* Revision 1.5 2004/08/13 23:36:05 justb
* rewrite of Pullet into Pushlet "pull" mode
*
* Revision 1.4 2003/08/15 08:37:40 justb
* fix/add Copyright+LGPL file headers and footers
*
* Revision 1.3 2003/08/12 09:57:05 justb
* replaced all print statements to Log.*() calls
*
* Revision 1.2 2003/05/18 16:15:07 justb
* support for XML encoded Events
*
* Revision 1.1.1.1 2002/09/24 21:02:30 justb
* import to sourceforge
*
* Revision 1.1.1.1 2002/09/20 22:48:17 justb
* import to SF
*
* Revision 1.1.1.1 2002/09/20 14:19:02 justb
* first import into SF
*
* Revision 1.5 2002/04/15 20:42:41 just
* reformatting and renaming GuardedQueue to EventQueue
*
* Revision 1.4 2000/12/27 22:39:35 just
* no message
*
* Revision 1.3 2000/10/30 14:15:47 just
* no message
*
*
*/
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