What does the following tell you?
interfaz_dbms.cacheable temp;
temp = interfaz_dbms.cache.getReferencia().Buscar(id,n.getTipo());
// add this code below...
if (temp!=null) {
System.out.println("class >" + temp.getClass() + "<");
}
// back to your code...
n = (materia.materias)temp;
Whatever is output between the >< symbols should be what you're trying to
cast to. That code above is not meant to be used to program better (don't
try to use that code for 'real'), only to help others on the list diagnose
what the class is/should be.
For example, if we see the output:
Class >Materia.materias< that means you haven't spelt the package named
correctly in your cast (Java is case-sensitive).
> -----Original Message-----
> From: Claudio Veas [mailto:[EMAIL PROTECTED]
> Sent: Monday, June 19, 2006 4:15 PM
> To: users@tomcat.apache.org
> Subject: Interfaces and cast problems in Tomcat
>
>
> Hello my name is Claudio Veas Im very new in tomcat develop
> and I was trying to use an interface to implement a cache. I
> make all the objects that I wanted to keep in memory
> implement "cacheable" interface so I could insert them into a
> Vector and then minimize the timing when looking for the same
> information.
>
> I dont have problems storing information in cache, and I dont
> have problems when I try to retrieve directly to a variable
> declared "cacheable" but when I try a direct cast the server
> shows me this error
>
>
>
> type Informe de Excepción
>
> mensaje
>
> descripción El servidor encontró un error interno () que hizo
> que no pudiera rellenar este requerimiento.
>
> excepción
>
> org.apache.jasper.JasperException: materias.materias
>
> org.apache.jasper.servlet.JspServletWrapper
> handleJspException(JspServletWrapper.java:510)
>
>
> org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper
> java:393)
>
>
> org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet
> .java:314)
>
>
> org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
>
> javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
>
>
>
> causa raíz
>
> java.lang.ClassCastException: materias.materias
>
> materia.experto_materias.getmaterias(experto_materias.java:54)
>
> org.apache.jsp.buscatema_jsp._jspService(buscatema_jsp.java:88)
>
>
> org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
>
> javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
>
>
> org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper
> java:332)
>
>
> org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet
> .java:314)
>
>
> org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
>
> javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
>
>
>
> nota La traza completa de la causa de este error se encuentra
> en los archivos de diario de Apache Tomcat/5.5.16.
>
>
>
> Here are the interface and the classes
>
>
>
>
>
> CACHEABLE
>
> package interfaz_dbms;
>
>
>
> public interface cacheable {
>
> public int getId();
>
> public int getTipo();
>
> }
>
>
>
> CACHE (some cache procedures )
>
>
>
> public void agregar(cacheable obj){
>
> Enumeration e=memoria.elements();
>
> while(e.hasMoreElements()){
>
> cacheable temp = (cacheable) e.nextElement();
>
> if(obj.getId()==temp.getId()||obj.getTipo()==temp.getTipo()){
>
> return;
>
> }
>
>
>
> }
>
> memoria.addElement(obj);
>
> }
>
>
>
> MATERIAS (this procedures gets all the "materias" (subjects)
> that a profesor teaches,
>
> and i saves it in the cache object)
>
>
>
> public static Vector getMateriaProf(int id){
>
> Vector v=new Vector();
>
> try{ String consulta ="SELECT
> m.id_materia,m.nombre,m.descripcion " +
>
> " FROM materia m, mat_profe mp, profesor p " +
>
> " WHERE m.id_materia = mp.id_materia " +
>
> " AND p.id_profesor = mp.id_profesor " +
>
> " AND p.id_profesor=" + String.valueOf(id);
>
> ResultSet rs =
> conneccion.getconection().Consultar(consulta);
>
> rs.next();
>
> while(!(rs.isAfterLast())){
>
> materias m=new
> materias(rs.getInt("id_materia"),rs.getString(
> nombre"),rs.getString("descripcion"));
>
> v.addElement(m);
>
> if(cache.getReferencia().EstaEn(m)==null){
>
> cache.getReferencia().agregar(m);
>
> }
>
> rs.next();
>
> }
>
>
>
> }
>
> catch(SQLException e){
>
>
>
>
>
> }
>
> return v;
>
> }
>
>
>
> EXPERTO MATERIAS (in some other page I request one of the
> "materias" but before going to the
>
> database again I search for it in memory I retrieved into a
> cacheable object and when I try the casting the error show up
>
>
>
> )
>
>
>
> public materias getmaterias(int id){
>
> materias n = new materias();
>
> interfaz_dbms.cacheable temp;
>
> temp =
> interfaz_dbms.cache.getReferencia().Buscar(id,n.getTipo());
>
> n = (materia.materias)temp;
>
> if(temp==null){
>
> n = materias.consultar(id);
>
> }
>
> return n;
>
> }
>
>
>
>
>
>
>
> I really hope I ve been clear enough and I hope you can help
> me out with this problems.
>
> Please excuse my english Im not very good at it
>
> Thanks on advance
>
> Claudio Veas
>
---------------------------------------------------------------------
To start a new topic, e-mail: users@tomcat.apache.org
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
