#taglib

Dancing QT is a combined music database and player application specially designed for dancing schools and equivalent applications. Key features are an easy-to-use interface, fast search capabilities, playlist management, exact pitching and crossfading. Looking around the open source landscape for a while, I tried to find a music database and player that is suitable for use in a dancing school…

Photo Organization via PowerShell and Tags (Part 2)

In Part 1of trying to tame my photos, I tried to wrangle my horribly organized photo library.  My organization skills were lacking, like many, when it comes to photos.  We take them, we import them or save them and then we… forget about them.  That’s a problem when I’m trying to handle large amounts of them (22.8 GB in 13,316 files) and organize them in ways that seem sensible.  To use this we…

Photo Organization via PowerShell and Tags

No one could ever accuse me of being a shutterbug.  I’m more of a casual photographer and muchmost of that was from mobile devices.  But that’s not the be-all-end-all.  I’ve also got scores of scans of old photographs, screenshots, and a bunch of other graphics that have accumulated over the years.  Thankfully modern mobile devices tag photos with a plethora of information.  Now it’s just a…

It is very common to see scriptlets inside AEM JSPs. I know! is not a very good looking JSP.

To improve the code readability JSP Standard Tag Library (JSTL) is recommended. There might be scenarios where JSTL is not enough and some coding is needed inside the JSP context. A good approach to handle this, and keep avoiding scriplets is Custom Tag Libraries.

A custom tag library is kind of a JSP helper for your code. You can call a custom tag library and make it perform some task(s), and then retrieve the values from the context.

By using this approach you can create reusable, maintainable, scalable Java classes, that might help different AEM components on similar tasks.

For a taglib to be used there are a couple of rules that need to be meet.

The OSGI bundle containing the tag library classes needs to have the a Tag Library Descriptors file (.tld). “A tag library descriptor is an XML document that contains information about a library as a whole and about each tag contained in the library. TLDs are used by a web container to validate the tags and by JSP page development tools.”

This TLD needs to have a unique identifier between all system available tag libraries. This identifier will be used to reference the library from a JSP context.

On this post I will describe you how to setup tag library support.

Spring mvc 튜토리얼을 따라 해보고 있는다 다음과 같은 에러 메시지가 나타나더군요.

Cannot resolve taglib with uri http://java.sun.com/jsp/jstl/core

원인은 JSP 파일의 첫번째 구문 때문이였습니다.

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>

그리고 실재로 해당 파일 http://java.sun.com/jsp/jstl/core 은 존재하지 않았고요.

# 해결방법

해결 방법은 의외로 쉬운데, 메이븐에서 JSTL 에 대한 의존성을 추가하는 것입니다.

<dependency> <groupId>jstl</groupId> <artifactId>jstl</artifactId> <version>1.2</version> </dependency>

위 코드를 추가했더니, 오류가 사라지더군요. 그런데 해당 URI 가 어떻게 라이브러리 하나 추가로 해결될지 궁금해졌습니다.

# 조금 더 들어가 보기

해당 라이브러리에는, c.tld 라는 파일이 존재합니다. 해당 파일에 아래와 같은 내용이 있습니다.

<taglib xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-jsptaglibrary_2_1.xsd" version="2.1"> <description>JSTL 1.1 core library</description> <display-name>JSTL core</display-name> <tlib-version>1.1</tlib-version> <short-name>c</short-name> <uri>http://java.sun.com/jsp/jstl/core</uri> <!-- 생략 --> </taglib>

위에 uri 속성이 http://java.sun.com/jsp/jstl/core 라고 되어 있네요, Tag Library Descriptors페이지에서 해당 내용을 찾아보니,

A URI that uniquely identifies the tag library.

Elementos necesarios

JSP. Java Servlet Page ... Contenedora de la presentación, convina html, taglibs y java.

TLD. Fichero XML descriptivo del tag.

Clase extendidad del Tag. Contiene el comportamiento del tag y extiende de javax.servlet.jsp.tagext.TagSupport

¿Cómo usar los taglibs?

Ejemplo simple. 

Ejemplo abanzado. Cómo crear un paginador.

Catálogo de taglibs … no está muy completo, pero no he encontrado mucho mas :(

¿Cómo motarlo?

Paso a paso muy completo sobre como crear un taglib.

Código de ejemplo (en inglés).

Acceder a los parámetros de sesión, a la request o a la response desde la clase del Tag.

Los parámetros de sesión son accesibles desde el atributo protegido pageContext de la clase javax.servlet.jsp.tagext.TagSupport ().

Accederemos a la sesión de la siguiente formapageContext.getSession();

Accederemos a la request de la siguiente forma pageContext.getRequest();

Accederemos a la response de la siguiente formapageContext.getResponse();

Vea el enlace de javadoc de pageContext

Most of people who know me, know I've been working on being more involved with my Twitter account. I've been trying to find ways to not only cross-post my inspirations, but also to interact and shout out my favorite people.

So, while at work a few days ago I was brainstorming something that could be a twitter "game". One of the first things I was thinking was how to engage other users by @-ing them in a tweet. Kind of like a "tag, you're it" situation. Of course there was already a kind of Twitter Mad Lib: MadTwibs which was it's own kind of fun. @Libs allows you to generate a funny sentence.

But, seeing as how there were just so many users, and plenty of them being nouns or verbs, I came up with the idea of TagLib. In which you tag either 1 friend or someone you follow as the subject. Search users for actions and nouns (below I'll post some to get you started). And then, finish it up with a friend or who you follow if possible. 

The goal is to make Twitter a little more interactive and fun. If you have a cause you're passionate about, tie the TagLib to that. Or if you're marketing something you've worked on or are launching, use a TagLib to spread the word.

RULES

1. Anyone can start a TagLib on any subject. You can make it as vague or targeted as possible. Meaning sometimes you can intentionally leave one verb or noun unchangeable.

2. Each one must have the hashtag: #TagLib so people can search and be apart of trending ones if they choose to.

3. It is not essential to have a link/url in a TagLib but it's allowed.

4. The goal is engagement with not only friends/followers but also people you may not have ever met, so search out new Twitter users.

5. You may change tense (adding -ed or -ing) or pluralize (adding -s) if you cannot find a user to get your idea across.

EXAMPLES

Just to get you started, here is what a TagLib should look like:

@shootbydaylight @spew -ed his @milk onto a @ballerina after he saw the @artofFLIGHT http://youtu.be/kh29_SERH0Y #TagLib

IDEAS

Nouns: @drunkmuffin @pattycake @whore