Chris Corbyn

Brilliant, thank you

I have a series of Amazon EC2 instances I wish to hold the addresses for in my build.xml file. For a particular target I would like to loop through all of these addresses and issue a command to the server. I can do it for one at a time; but I'm not sure how to create the equivalent of a Collection in the build.xml and then how to loop through that Collection.

In pseudo:

<collection id="servers"> <item value="server-one.tld" /> <item value="server-two.tld" /> <item value="server-three.tld" /> </collection> <target name="updateinstances"> <foreach collectionref="servers" ...> <!-- do something --> </foreach> </target>

I'm sure it's staring me in the face when reading the documentation but I'm missing it. Any hints?

I think the wording is perhaps a bit misleading. "User" refers to the local client I assume, and in which case if you only read from the server when the local client sends a message then you would only ever know if the remote client in the chat has said anything once you say something.

I'm using jMock (which is awesome by the way) for my mock objects because it's simple to generate the mocks and make expectations with it.

jMock allows me to create mock objects from the servlet spec interfaces with a few lines of code so I'm happy for now There's actually only a handful of objects which *need* to be mocked/stubbed in order for things to work.

Originally posted by Gabriel Claramunt:
Can you use JSF? If you insist, IS part of J2EE and you only need POJOs, very easy to test. If you experienced the pain of working with plain JSPs and servlets, JSF is a blessing

Right now my J2EE knowledge extends to: Servlets, JSP, Tag Libraries (and JSTL) and EL. JSF was on my "to learn" list but with what you're saying I should really look at that now then

Cheers.

PS: Oh yeah, I'll never (ever ever ever) need to test anything in my JSP code Just templates, that's all I use JSP for

Originally posted by Peer Reynders:
JavaWorld: Testing J2EE applications (2004-Aug)
J.B. Rainsberger (Diaspar): Test-Driven J2EE

[ September 10, 2007: Message edited by: Peer Reynders ]

I've only got to the 4th page in that article on JavaWorld and already I feel like they're testing too much. I personally don't want to simulate a web browser and/or a user clicking a link on a page right now. I'd rather create a mock of HttpServletRequest, set the request uri and some parameters and pass that mock to my servlet while I test how it behaves. I may find a need for that depth of testing later once I start testing pages built inside my framework, but not now

I'll finish Frank's article then I'll grab JUnit and wrap my head around how people create Mocks in Java and I'll get started

Originally posted by Stan James:
Spring's inventor wrote about the power of POJOs - Plain Old Java Objects - before he did Spring. Spring dependency injection is just one way to isolate your POJOs from J2EE. You can do it on your own.

One idea is to reduce the classes that know about HTTP, Session, Request, Response, EJB, etc. to minimal gateways. They do as little as possible before handing off responsibility to classes with no J2EE imports. For example, a servlet might copy all the request parameters into a HashMap and call a POJO. (You asked about doing this "without a framework" but you're really building a smallish framework at this point.)

Now you don't have a J2EE question any more. You can TDD all your POJOs without thinking about servlet or EJB containers.

Is that the kind of thing you're looking for?

This is one approach I considered taking, but J2EE is J2EE. It offers a lot and (IMHO), hiding it from the commands/actions would be a waste. I've taken a K.I.S.S approach with my non TDD version and simply give ServletContext, ServletRequest and ServletResponse to the individual actions controllers before heading off to a View (JSP) -- if requested.

[Request in] | v Request Mapper (FilterChain) | v FrontController (HttpServlet) | V ActionController.init(ServletContext, ServletRequest, ServletResponse) | v ActionController.validate() --- [no] --> ActionController.handleError() | [yes] | v ActionController.execute() | v Main JSP (layout) <--- include --- Page template | v [Response out]

I'm not planning on Unit Testing what I've already written because I don't find that particularly useful. I know it works. I find unit testing more useful as a driving force in development so I'll be going back to scratch.

It would be a shame to have to hide the fact the environment is J2EE by writing my own objects for things that J2EE already provides. Really it wouldn't be too much effort to create mock objects from the APIs in the spec and test with those but I didn't really know if that was a done thing. It's fortunate J2EE has such a complete spec which you can rely on.

Peer, thanks for the links I'll have a read Frank, I still didn't get through your second article because my boss spat his dummy out when he caught me reading it while I was supposed to be working on a PHP project Meh, I don't care, I leave for Oz in 2 weeks

Thanks again guys.

Reading it now thanks. I read the first one which was aptly agile though no mention of tests just yet having only just written a little interface. I'll keep going I'm aware that some of the content is out of date, being over 4 years old now

PS: I really like browsing/reading the Journal but it looks like things are on a slow down lately... unless I'm missing where the 2007 articles are?

I create screen.xml files for this... one per-screen in, for example /WEB-INF/screens/documentation/contents.xml:

<?xml version="1.0" ?> <screen> <title>project documentation - My project</title> </screen>

Now just use XPath to query what you need. I have a ScreenFactory object which creates a simple bean from the configuration. I also store 'fragments', CSS files, JS files and Meta data in here.

I've come from a PHP background where I used to develop with TDD religiously but moved to Java a couple of months ago. I feel like I've gotten to grips with the language enough to at least get back into Unit Testing. I've tried searching around for some inspriation on how to approach test driven development within a servlet environment but all I keep coming across is spring and hibernate articles....

Does anyone have any good links to articles which provide some insight into using JUnit on a J2EE server without being tightly bound to a particular framework (in my case I'm writing my own framework as part of my self-teaching).

I updated it to use an indexed setter system like so:

/* A bean which wraps an Iterator to keep cycling around rather than ending. */ package beans; import java.util.List; import java.util.ArrayList; import java.util.Iterator; /** * A bean which wraps an Iterator to keep cycling around rather than ending. * @author Chris Corbyn <chris@w3style.co.uk> */ public class Rotator <T extends String> { /** The List which is being wrapped */ protected List<T> list; /** The Iterator for the list */ protected Iterator<T> it = null; /** * No argument constructor for bean. */ public Rotator() { setList(new ArrayList<T>()); } /** * General use constructor allowing the list to be passed. * @param T[] collection */ public Rotator(T[] list) { setItems(list); } /** * Set the List being wrapped. * @param List<T> list */ public void setList(List<T> list) { this.list = list; } /** * Get the List being wrapped. * @return List<T> */ public List<T> getList() { return list; } /** * Add a new item. * @param T item */ public void addItem(T item) { list.add(item); } /** * Get the item at index i. * @param int i * @return T */ public T getItem(int i) { return list.get(i); } /** * Add an indexed item. * @param int i * @param T item */ public void setItem(int i, T item) { list.add(i, item); } /** * Set the entire list of items from an array. * @param T[] items */ public void setItems(T[] items) { setList(new ArrayList<T>()); for (int i = 0; i < items.length; i++) { setItem(i, items[i]); } } /** * Get the entire list of items as an array. * @return String[] */ public String[] getItems() { Iterator<T> it = list.iterator(); String[] items = new String[list.size()]; int i = 0; while (it.hasNext()) { items[i] = it.next(); i++; } return items; } /** * Get the next item, or the first item if already at the end. * @return T */ public T getNext() { if (it == null || !it.hasNext()) { it = list.iterator(); } return it.next(); } }

It's implemented like this:

<div id="navigation_links"> <jsp:useBean id="color" class="beans.Rotator"> <jsp:setProperty name="color" property="items" value="${fn:split('green;orange;yellow;pink;blue', ';')}" /> </jsp:useBean> <ul> <jsp:useBean id="menu" class="beans.NavigationMenu" /> <c:forEach items="${menu.items}" var="item"> <c:choose> <c:when test="${item.active}"> <li><div class="nav_item ${color.next} on"> <div class="nav_link"> <mayo:link to="${item.url}">${item.text}</mayo:link> </div> <div class="nav_blank"></div> </div></li> </c:when> <c :-o therwise> <li><div class="nav_item ${color.next}"> <div class="nav_link"> <mayo:link to="${item.url}">${item.text}</mayo:link> </div> <div class="nav_blank"></div> </div></li> </c :-o therwise> </c:choose> </c:forEach> </ul> </div>

I have dynamic menu options which are displayed and they are colorful buttons on a dark background. I wanted to avoid the crazy logic determining what color to use in the JSP

Drum roll please.....

<navigation>
...
</naviagtion>

That was the root of my problem. I've got fat fingers. Now suddenly I don't care if I have to put try/catch around every call to DocumentFactory.getDocument() because I'd rather know what the problem is than just having a null return value

EDIT | Scrap that. Confused
[ September 09, 2007: Message edited by: Chris Corbyn ]

In my servlet/JSP app I have a handful of XML files which all sit in /WEB-INF and get accessed from various different places (Filters, Controllers, Beans...). I started out using servletContext.getResourceAsStream() and then using DocumentBuilder to create a new Document object.

The problem with that was that I was:

a) Needing to pass ServletContext around all components which need to read XML files
b) Creating multiple instances of the same Document needlessly.

So with that in mind I set about trying to create a singleton called DocumentFactory which contains ServletContext and a Map of already built Documents.

Early on in the FrontController invoke: DocumentFactory.getInstance().init(servletContext).

/* Creates and registers XML resources globally. This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ package org.mayo.util; import javax.servlet.ServletContext; import java.util.Map; import java.util.HashMap; import org.w3c.dom.Document; import javax.xml.parsers.DocumentBuilderFactory; import java.io.InputStream; /** * Prevents the overhead of repeatedly opening the same document in XML format * by registering created documents for global access. * @author Chris Corbyn <chris@w3style.co.uk> */ final public class DocumentFactory { /** This class as a singleton */ protected static DocumentFactory instance = null; /** The current ServletContext where resources can be found */ protected ServletContext context; /** The map which holds the registry internally */ protected Map<String,Document> map; /** * Constructor. */ protected DocumentFactory() { setMap(new HashMap<String,Document>()); } /** * Get the instance of this DocumentFactory. * @return DocumentFactory */ public synchronized static DocumentFactory getInstance() { if (instance == null) { instance = new DocumentFactory(); } return instance; } /** * Initialize the DocumentFactory with the ServletContext. * @param ServletContext context */ final public void init(ServletContext context) { this.setContext(context); } /** * Set the Map which holds the registry. * @param Map<String,Document> map */ protected void setMap(Map<String,Document> map) { this.map = map; } /** * Get the Map which holds the registry. * @return Map<String,Document> */ protected Map<String,Document> getMap() { return map; } /** * Set the ServletContext. * @param ServletContext context */ protected void setContext(ServletContext context) { this.context = context; } /** * Get the ServletContext. * @return ServletContext */ public ServletContext getContext() { return context; } /** * Get or create Document from the provided resource path. * Null is returned if no resource exists at the given path. * @param String path * @return Document */ public Document getDocument(String path) { Document document = null; Map<String,Document> map = getMap(); if (!map.containsKey(path)) { InputStream is = getContext().getResourceAsStream(path); if (is == null) { return document; } try { DocumentBuilderFactory builder = DocumentBuilderFactory.newInstance(); document = builder.newDocumentBuilder().parse(is); map.put(path, document); } catch (Exception e) { System.out.println( "Document building for path '" + path + "' failed. " + e); } } return map.get(path); } /** * Cleanup after this object is no longer needed. */ final public void destroy() { getMap().clear(); instance = null; } }

This worked great when I was just working within my servlet. But just recently I tried using it in a JavaBean from a JSP file. It always returns NULL for any document that wasn't used previously. The only difference between trying to use it from a JSP/JavaBean and using it from the servlet is that RequestDispatcher.forward() has been called.

I've pinned the problem down to this line:

InputStream is = getContext().getResourceAsStream(path); if (is == null) { return document; }

Is there a reason why servletContext (from the Servlet, before forward() was called) will not fetch resources *after* forward() has been called?

Is that a more elegant way to do what I'm trying to do?

Basically I just want a convenience class that can grab me a XML file from WEB-INF and can be accessed from anywhere within the current context.

Thanks for the help if anybody actualy gets to the end of this thread

Both points taken on board and agreed with I'll rewrite the bean. I think I need to implement a getNext() method because I do need some way of making it iterate cyclically.

The reason it's needed is for alternating colors (but more than just two colors). I wanted to avoid too much complex bitwise logic inside the JSP itself.

Rather than the typical boolean negation or modulus operations I can just keep using ${color.next} and let the bean deal with that logic.