Java API - Estrutura de árvore.

Olá,

 

Gostaria de saber se alguém conhece uma Java API para trabalhar com uma estrutura de árvore, por exemplo

 

                A

               /  \

             B    C

            /  \ 

          D    E

 

Grato.

 

Márcio.

Bom dia ,

 

To Usando o struts 1.3.9 e não consigo retornar as ActionMessage. Qdo simulo um erro, não o recebo do ActionForm. Alguma ajuda???

 

Por exemplo, fiz um teste....

 

package br.com.surson.negocio;

 

import java.util.Iterator;

import java.util.LinkedList;

 

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

 

import org.apache.struts.action.ActionErrors;

import org.apache.struts.action.ActionForm;

import org.apache.struts.action.ActionForward;

import org.apache.struts.action.ActionMapping;

import org.apache.struts.action.*;

 

public class ExcluirCursosAction extends Action{

                public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request,

                                               HttpServletResponse response)throws Exception {

                              

                               ActionErrors errors = new ActionErrors();

                              

                               try{

                                               HttpSession s = request.getSession();

 

                                               String idCurso = request.getParameter("idCurso");

                                               // remove o bean da pagina altera jsp para garantir que não haja sugeira

                                              

                                               // traz a lista de cursos para poder listá-los afim de achar o que bate com a solicitação

                                               LinkedList listaCursos = (LinkedList)s.getAttribute("listabean");

                                               Iterator i = listaCursos.iterator();

                                               while (i.hasNext()){

                                                               Curso curso = (Curso) i.next();

                                                               if (curso.getIdCurso()== Integer.parseInt(idCurso)){

                                                                              AdminCursos c = new AdminCursos();

                                                                              c.excluirCurso(curso);

                                                                              LinkedList lista = c.obterListasCursos();

                                                                              s.setAttribute("listabean", lista);

                                                                              break;

                                                               }

                                                              

                                                                

                                               }

                                              

                               }catch (Exception e) {

                                              

                                               return(mapping.findForward("failure"));

                               }

                               return(mapping.findForward("success"));

                              

                              

                }

}

 

 

package br.com.surson.negocio;

import javax.servlet.http.HttpServletRequest;

import org.apache.struts.action.*;

import org.apache.struts.action.ActionErrors;

import org.apache.struts.action.ActionMessage;

// função de lidar com os campos do nosso formulário... Ele Validam e resetam

public class SalvarCursoForm extends ActionForm{

     

      private int idCurso;

      private String curso;

      public void reset(ActionMapping mapping, HttpServletRequest request){

            idCurso = 0;

            curso = "";

                  }

      public ActionErrors validate(ActionMapping mapping, HttpServletRequest request){

            ActionErrors errors = new ActionErrors();

            if (( curso == null) || (curso.length()<1)){

                  errors.add("curso", new ActionMessage("Curso é requerido"));

                  }

            return errors;

      }

      public void setIdCurso(int idCurso){

            this.idCurso = idCurso;

      }

      public int getIdCurso(){

            return this.idCurso;

      }

      public void setCurso(String curso){

            this.curso = curso;

      }

      public String getCurso(){

            return this.curso;

      }

}

 

 

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%>

<%@ page import = "br.com.surson.negocio.*" %>

<%@ page import = "java.util.*" %>

<%@ taglib uri="http://struts.apache.org/tags-bean" prefix="bean"  %>

<%@ taglib uri="http://struts.apache.org/tags-logic" prefix="logic"  %>

<%@ taglib uri="http://struts.apache.org/tags-html" prefix="html"  %>

 

<logic:notPresent name="incluirCursoBean" scope="session" >

  <logic:redirect forward="error"/>

</logic:notPresent>

 

 

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html:html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">

<title>Incluir Curso</title>

</head>

<body>

<center>

<br>

                                               <html:form action="incluirNovoCurso.do"  method="get">

                                                              

                                                               <table border = 0 >

                                                              

                                                               <tr>

                                                                              <td align="rigth"  Curso:></td>

                                                                              <td align="left" ><b>

                                                                                                              <html:text property="curso" name="incluirCursoBean" />

                                                                                                              </b>

                                                                                                              </td>

                                                                              </tr>

 

                                                                               <tr>

                                                                                              <td colspan=2 align="center">

                                                                                              <html:submit>Incluir</html:submit>

                                                                                              <html:reset>Cancelar</html:reset>

                                                                                              </td>                    

                </tr>

                                                               </table>

  

                                                               </html:form>

   <logic:messagesPresent message="true" > 

                                                                               <html:messages id="curso" message="true">  

                                                                              <bean:write name="curso" />  

                                                                              </html:messages>

</logic:messagesPresent> 

                                                              

</body>

</html:html>

 

<?xml version="1.0" encoding="ISO-8859-1" ?>

 

 

 

<struts-config>

 

 

<!-- ================================================ Form Bean Definitions -->

 

    <form-beans>

    <form-bean dynamic="false"  name="salvarCursoForm"  type="br.com.surson.negocio.SalvarCursoForm"/>

    <form-bean dynamic="false"  name="incluirCursoForm"  type="br.com.surson.negocio.IncluirCursoForm"/>

    </form-beans>

 

 

<!-- ========================================= Global Exception Definitions -->

 

    <global-exceptions>

       

    </global-exceptions>

 

 

<!-- =========================================== Global Forward Definitions -->

 

    <global-forwards>

        <!-- Default forward to "Welcome" action -->

        <!-- Demonstrates using index.jsp to forward -->

        <forward

            name="welcome"

            path="/Welcome.do"/>

         <forward name="failure"

                path="/pages/error.jsp" redirect="false" contextRelative="false"/>

               

 

    </global-forwards>

 

 

<!-- =========================================== Action Mapping Definitions -->

 

    <action-mappings>

 

            <action path="/listaCursos"

                               scope="session"

                               unknown="false"

                               validate="false"

                               type="br.com.surson.negocio.ListaCursosAction">

                <forward

                               name="success"

                               path="/pages/listacursos.jsp"

                               redirect="false"

                               contextRelative="false">

                </forward>

            </action>

            <action path="/alterarCursos"

                scope="session"

                unknown="false"

                validate="false"

                type="br.com.surson.negocio.AlterarCursosAction">

                <forward

                               name="success"

                               path="/pages/alterarcursos.jsp"

                               redirect="false"

                               contextRelative="false">

                </forward>

            </action>

           

            <action

                               path="/salvarCurso"

                               attribute="salvarCursoForm"

                               input = "/pages/alterarcursos.jsp"

                               name="salvarCursoForm"

                               scope="session"

                               unknown="false"

                                validate="true"

                                type="br.com.surson.negocio.SalvarCursoAction">

                <forward

                                               name="success" 

                                               path="/pages/listacursos.jsp"

                                               redirect="false"

                                               contextRelative="false">

                </forward>

            </action>

            <action

                               attribute="incluirCursoForm"

                               input = "/pages/incluircurso.jsp"

                               name="incluirCursoForm"

                               path="/incluirNovoCurso"

                               scope="session"

                               unknown="false"

                                validate="true"

                                type="br.com.surson.negocio.SalvarNovoCursoAction">

                <forward

                                               name="success" 

                                               path=