JavaSnippets

To do quick-'n'-dirty timing:

    boolean debug = true;
    long startTime = System.currentTimeMillis();
    if (debug) {
        out.println("Elapsed: " + ( System.currentTimeMillis() - startTime ) +
                    " milliseconds");
    }

To get the full stacktrace in a String (this should've been part of the API):

    try {
        // Do stuff
    } catch (Exception e) {
        StringBuffer sb = new StringBuffer();
        StackTraceElement st[] = e.getStackTrace();
        sb.append(e.getMessage() + "\n");
        for (int i = 0; i < st.length; i++)
            sb.append("at " + st[i].getClassName() + "." +
                      st[i].getMethodName() + "(" +
                      st[i].getFileName()+": " + 
                      st[i].getLineNumber() + ")");
    }

To put a long-running query in the background, and keep refreshing your JSP until it's done (there are better ways!):

    public class TestThread extends Thread
    {
    
    	private Connection conn;
    	private boolean debugging = false;
        private StringBuffer runtime;
    
    	public TestThread( Connection conn, StringBuffer runtime )
    	{
    		this.conn = conn;
            this.runtime = runtime;
    	}
    
    	public void run() {
            // Clean 'em (shouldn't be necessary)
            try {
                Statement stmt = conn.createStatement();
                ResultSet rs = stmt.executeQuery( "select sysdate()" );
                rs.next();
                Date d = rs.getDate(1);
                long startTime = System.currentTimeMillis();
                try {
                	Thread.sleep(1000*20); // Sleep 20 seconds
                } catch (InterruptedException ie) {
                    // Do nothing
                }
                runtime.append(d);
            } catch (SQLException se) {
            	runtime.append("-1");
            }
    	}
    }

And here's the JSP page that keeps refreshing:

	<%@ page language="java" session="true" import="blahblah"%>
	<html>
	<head>
		<title>ThreadTest</title>
	<%
	    Connection conn = null; // obtain your connection
	
	    // Set URL
	    String refreshURL = request.getRequestURL().toString();
	    
	    // See if thread was fired
	    StringBuffer runtime = null;
	    Object obj = session.getAttribute("TestThreadRuntime0");
	    if( obj == null ) {
	        // Thread hasn't been fired before. Start it.
	        runtime = new StringBuffer("");
	        session.setAttribute("TestThreadRuntime0", runtime);
	        TestThread tt = new TestThread( conn, runtime );
	        tt.start();
	    } else {
	        // Thread has fired before. See whether it's finished.
	        runtime = (StringBuffer) obj;
	    }
	    
	    // See if we're finished
	    boolean done = false;
	    if (runtime.length() > 0) {
	        done = true;
	    }
	    
	    if (!done) {
	%>
	    <meta http-equiv="Refresh" CONTENT="3; url=<%= refreshURL %>">
	<%
	    }
	%>
	</head>
	<body>
	<%
	    if (!done) {
	%>
	    Not done yet...
	<p>
	    <%= obj %>
	<%
	    }
	    else
	    {
	        // Reset stuff for next run
	        session.setAttribute("TestThreadRuntime0", null);
	%>
	    We're done!! Runtime: <%= runtime %>
	    
	<%
	    }
	%>
	</body>
	</html>