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The Java package ch.aplu.turtle provides a professional and stable version of OOP-based turtle graphics since more than 6 years. The library is used in many introductory programming courses and achieved teachers satisfaction. Using Jython, turtles can be created and controlled interactively now, providing a pleasant subject for the "first hour of programming". It's like LOGO with the advantage that multiple turtles may be created, so turtles are really "objects" in the common sense of the word. Because the turtle movements (forward/backward steps and rotations) are animated and the turtle shapes are cute (not a simple triangle), introducing programming concepts like interations, selections, functions and recursion is a pleasure.
Depending on your didactical intensions you want to emphasize object orienting programming from the very beginning or start your course with global variables. (In Java you don't have the choice because global variables are not supported). If you opt for the second concept, TigerJython lets you create a global turtle by importing gturtle and calling makeTurtle(). All turtle methods are available in Python's global namespace. Consult the JavaDoc for the Turtle methods.
Programs now become extremely simple, just like in C, Basic or Logo. This example shows the most fundamental concept of informatics: "A computer program is a sequence of instructions that are executed step-by-step".
Error Page
Error Page
Stack trace:
java.io.FileNotFoundException: The requested resource [/home/pyincludes/TuEx1.html] is not available
at org.apache.catalina.servlets.DefaultServlet.serveResource(DefaultServlet.java:845)
at org.apache.catalina.servlets.DefaultServlet.doGet(DefaultServlet.java:497)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
at org.apache.catalina.servlets.DefaultServlet.service(DefaultServlet.java:477)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
at sun.reflect.GeneratedMethodAccessor64.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.apache.catalina.security.SecurityUtil$1.run(SecurityUtil.java:282)
at org.apache.catalina.security.SecurityUtil$1.run(SecurityUtil.java:279)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAsPrivileged(Subject.java:549)
at org.apache.catalina.security.SecurityUtil.execute(SecurityUtil.java:314)
at org.apache.catalina.security.SecurityUtil.doAsPrivilege(SecurityUtil.java:170)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:225)
at org.apache.catalina.core.ApplicationFilterChain.access$000(ApplicationFilterChain.java:47)
at org.apache.catalina.core.ApplicationFilterChain$1.run(ApplicationFilterChain.java:149)
at org.apache.catalina.core.ApplicationFilterChain$1.run(ApplicationFilterChain.java:145)
at java.security.AccessController.doPrivileged(Native Method)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:144)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:712)
at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:580)
at org.apache.catalina.core.ApplicationDispatcher.access$100(ApplicationDispatcher.java:64)
at org.apache.catalina.core.ApplicationDispatcher$PrivilegedInclude.run(ApplicationDispatcher.java:113)
at org.apache.catalina.core.ApplicationDispatcher$PrivilegedInclude.run(ApplicationDispatcher.java:101)
at java.security.AccessController.doPrivileged(Native Method)
at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:507)
at org.apache.jasper.runtime.JspRuntimeLibrary.include(JspRuntimeLibrary.java:955)
at org.apache.jsp.jython_005fex1_jsp._jspService(jython_005fex1_jsp.java:166)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:71)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:477)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:385)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:329)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
at sun.reflect.GeneratedMethodAccessor64.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.apache.catalina.security.SecurityUtil$1.run(SecurityUtil.java:282)
at org.apache.catalina.security.SecurityUtil$1.run(SecurityUtil.java:279)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAsPrivileged(Subject.java:549)
at org.apache.catalina.security.SecurityUtil.execute(SecurityUtil.java:314)
at org.apache.catalina.security.SecurityUtil.doAsPrivilege(SecurityUtil.java:170)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:225)
at org.apache.catalina.core.ApplicationFilterChain.access$000(ApplicationFilterChain.java:47)
at org.apache.catalina.core.ApplicationFilterChain$1.run(ApplicationFilterChain.java:149)
at org.apache.catalina.core.ApplicationFilterChain$1.run(ApplicationFilterChain.java:145)
at java.security.AccessController.doPrivileged(Native Method)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:144)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:712)
at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:580)
at org.apache.catalina.core.ApplicationDispatcher.access$100(ApplicationDispatcher.java:64)
at org.apache.catalina.core.ApplicationDispatcher$PrivilegedInclude.run(ApplicationDispatcher.java:113)
at org.apache.catalina.core.ApplicationDispatcher$PrivilegedInclude.run(ApplicationDispatcher.java:101)
at java.security.AccessController.doPrivileged(Native Method)
at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:507)
at org.apache.jasper.runtime.JspRuntimeLibrary.include(JspRuntimeLibrary.java:955)
at org.apache.jsp.printcenter_jsp._jspService(printcenter_jsp.java:157)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:71)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:477)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:385)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:329)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
at sun.reflect.GeneratedMethodAccessor64.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.apache.catalina.security.SecurityUtil$1.run(SecurityUtil.java:282)
at org.apache.catalina.security.SecurityUtil$1.run(SecurityUtil.java:279)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAsPrivileged(Subject.java:549)
at org.apache.catalina.security.SecurityUtil.execute(SecurityUtil.java:314)
at org.apache.catalina.security.SecurityUtil.doAsPrivilege(SecurityUtil.java:170)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:225)
at org.apache.catalina.core.ApplicationFilterChain.access$000(ApplicationFilterChain.java:47)
at org.apache.catalina.core.ApplicationFilterChain$1.run(ApplicationFilterChain.java:149)
at org.apache.catalina.core.ApplicationFilterChain$1.run(ApplicationFilterChain.java:145)
at java.security.AccessController.doPrivileged(Native Method)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:144)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
at sun.reflect.GeneratedMethodAccessor65.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.apache.catalina.security.SecurityUtil$1.run(SecurityUtil.java:282)
at org.apache.catalina.security.SecurityUtil$1.run(SecurityUtil.java:279)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAsPrivileged(Subject.java:549)
at org.apache.catalina.security.SecurityUtil.execute(SecurityUtil.java:314)
at org.apache.catalina.security.SecurityUtil.doAsPrivilege(SecurityUtil.java:253)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:191)
at org.apache.catalina.core.ApplicationFilterChain.access$000(ApplicationFilterChain.java:47)
at org.apache.catalina.core.ApplicationFilterChain$1.run(ApplicationFilterChain.java:149)
at org.apache.catalina.core.ApplicationFilterChain$1.run(ApplicationFilterChain.java:145)
at java.security.AccessController.doPrivileged(Native Method)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:144)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
at org.apache.coyote.ajp.AjpProcessor.service(AjpProcessor.java:432)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)
Request URL:
http://aplu.ch/home/printcenter.jsp
Parameters:
center_to_include: jython_ex1.jsp
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