Integrating RPG and Java Server Pages

Integrating RPG and Java Server Pages

Gulf Coast Midrange Users GroupWelcome

Topic

Gulf Coast Midrange Users Group

Problem: Web Development for AS/400-RPG shops unaccustomed to Java or other web development languages.

Welcome to: Integrating RPG and Java Server Pages

Java Server Pages Definition

JavaServer Pages. A server-side technology, JavaServer pages are an extension to the Java servlet technology that was developed by Sun. JSPs have dynamic scripting capability that works in tandem with HTML code, separating the page logic from the static elements -- the actual design and display of the page. Embedded in the HTML page, the Java source code and its extensions help make the HTML more functional, being used in dynamic database queries, for example. JSPs are not restricted to any specific platform or server.

Java Server Pages Requirements

● Java Server Pages require the

● Tomcat Jsp Container.

Jsp Example

<jsp:useBean id="LI" class="meatOrder.LoginMain" scope="request"> <%rtnCd = LI.Login();%><%if ((rtnCd.equals("1"))) { %> <jsp:forward page="Welcome.html"></jsp:forward> <% <% } else { %> <HTML> <HEAD> <TITLE>Login.jsp</TITLE> </HEAD> <BODY> <H2 align="center">Autry Greer and Son's, Inc.</H2> <FORM method="post" name="LogIn" action="http://S1041402/app1/jsp/Login.jsp"> <p align="center">User Id : <INPUT type="text" name="userId" size="10"></p> <p align="center">Password: <INPUT type="password" name="passWord" size="10"></p> <p align="center"><INPUT type="submit" name="logIn" value="Submit"></p> <INPUT type="hidden" name="rtncd" value=null></FORM> </BODY> </HTML> <% } %>

If rtnCd equals “1” forward user to Welcome pageElseRedisplay Login Page

Jsp to use java class LoginMain And refer to program as “LI”

Java Objects (Classes, Methods, Variables)

public class LoginMain {

* Program Variables */

public String userId = " ";public String passWord = " ";public String rtnCd = "0";

/** * Login native method */

public native String Login();

/** * Getter methods generated by Websphere */

/** Return User Id */public byte [] getUserId() {

return userId.getBytes();}

/** Return PassWord*/public byte [] getPassWord() {

return passWord.getBytes();}

Java program example contains:

1 java class (LoginMain)

3 variables(userId, passWord, rtnCd)

3 methods(Login, getUserId, getPassWord)

Note that method Logindoes not contan any codeand has the “native” modifier

While getUserId and getPasswordcontain code and are not “native”

The Java Native Interface

The Java Native Interface (JNI)

The JNI allows Java code that runs within a Java Virtual Machine (JVM) to operate with applications and libraries written in other languages, such as C, C++,Visual Basic and RPG ILE. In addition, the Invocation API allows you to embed the Java Virtual Machine into your native applications.

AS/400 Native RPGILE methods must be coded within Sub-Procedure Modules and made into Service Programs. The Service Program must reside within the library list.

Calling AS/400 Java Native Method Requirements

/** * Find Login Service Program */

static {System.loadLibrary("SRVLOGIN");

}



Call to “native” method “Login”

Find Service Program “SRVLOGIN” in library list

Jsp calling native RPG method/sub-procedure

<jsp:useBean id="LI" class="meatOrder.LoginMain" scope="request"> <%rtnCd = LI.Login();%>

<%if ((rtnCd.equals("1"))) { %> <jsp:forward page="Welcome.html"></jsp:forward>



3500 * Prototyped Native Java Method Login 3700 DLogin PR O Class(*JAVA:StringClass) 3800 D ExtProc(*JAVA 3900 D :LM 4000 D :LI) 4100 PLogin B Export 4200 DLogin PI O Class(*JAVA:StringClass)

JSP calls Java method Login

Java calls Native Method LoginFound in Service Program Srvlogin

Login Returns string ObjectrtnCd back to Java programthen to JSP

A

B

C

RPG and JNI ProtoTyping of “getter” method

/** Return User Id */

public byte [] getUserId() {return userId.getBytes();

} DGUI C 'getUserId' DLM C 'meatOrder.LoginMain' DLI C 'Login' * * Prototyped Java getUserId Method * B DgetUserId PR 10A D ExtProc(*JAVA D :LM D :GUI) DuserId S Like(GetUserId) C Eval UserId = getUserId(%This)

When the getUserId method is called in RPG it uses theJava method proto-typed

B

C

A

Java Method is a native method. Calls RPG Sub-Procedure

RPG Sub-Procedureperforms all businesslogic. Accesses databaseand returns status codeto java program and JSP

<%rtnCd = LI.Login();%>

Jsp makes call to Java program method

Visual Representation of Interaction

A B

CD

<%if ((rtnCd.equals("1"))) { %><jsp:forward page="Welcome.html"></jsp:forward><%

Jsp reacts to rtncd from RPG

JSP and RPG Integration Review

Java Native Interface (JNI) provides method of interfacing JSP's and RPG

RPG can access JSP forms thru prototyped “getter/setter” methods

Custom Tag Libs can improve development time often eliminating coding

NOTE

Two Main JSP Development FrameWorks:

Struts Java Server Faces

Java Server Faces Example

login.jsp

<%@ taglib uri="http://java.sun.com/jsf/html" prefix="h" %> <%@ taglib uri="http://java.sun.com/jsf/core" prefix="f" %> <f:loadBundle basename="bundle.Messages" var="Message" /> <html> <head><title>Login</title></head> <body> <f:view> <h:form id="loginForm" > *<h:message for="loginForm" /><br /> <h:outputText value="#{Message.username_label}" /> <h:inputText id="username" value="#{LoginMain.userName}" required="true" > <f:validateLength maximum="15" minimum="3" /> </h:inputText> <h:message for="username" /><br /> <h:outputText value="#{Message.password_label}" /> <h:inputSecret id="password" value="#{LoginMain.passWord}" required="true" > <f:validateLength maximum="15" minimum="3" /> </h:inputSecret> <h:message for="password" /><br /> <h:commandButton id="submit" action="#{LoginMain.login}" value="#{Message.login_button}" /> </h:form> </f:view> </ body > </ html >

<h:commandButton id="submit" action="#{LoginMain.Login}" value="#{Message.login_button}" />



3500 * Prototyped Native Java Method Login 3700 DLogin PR O Class(*JAVA:StringClass) 3800 D ExtProc(*JAVA 3900 D :LM 4000 D :LI) 4100 PLogin B Export 4200 DLogin PI O Class(*JAVA:StringClass)

JSF calls Java Method

Java method is a “native” method

Calls RPG Sub-Procedure

Java Server Faces and RPG Interaction

faces-config.xml

<navigation-rule> <from-view-id>/Login.jsp</from-view-id> <navigation-case> <from-outcome>1</from-outcome> <to-view-id>/welcome.jsp</to-view-id> </navigation-case> <navigation-case> <from-outcome>0</from-outcome> <to-view-id>/Login.jsp</to-view-id> </navigation-case> </navigation-rule>

Java Server Faces Navigation

Conclusion

The integration of JSP and RPG can provide AS/400 developers unaccustomed to java development an inroad to more rapid web development.

RPG using JSP integration can “get/set” variables normally only reserved for java objects from the Apache HTTP/Tomcat JSP server.

Thank You and support your GCMUG

Integrating RPG and Java Server Pages

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