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Created by Fang on November 22, 2011 10:40:16    Last update: November 22, 2011 10:40:16
This is an example that uses tag handler, UI component and renderer together to support a custom taglib. The main purpose is to show how these components play together. The tag renders <ui:param name="extra" value="el interpreted"/> ... as <h3>my:foreach</h3> <ul class="css class" extra... These are the files: The tag handler ( src/main/java/com/example/ForeachTagHandler.java ): package com.example; import java.util.Map; ... The UI component ( src/main/java/com/example/UIForeach.java ): package com.example; import java.io.IOExcep... The renderer ( src/main/java/com/example/ForeachRenderer.java ): package com.example; import java.io.IOExcep... Faces config ( src/main/resources/META-INF/faces-config.xml ): <?xml version="1.0" encoding="UTF-8"?> <faces-c... Taglib config ( src/main/resources/META-INF/foreach.taglib.xml ): <?xml version="1.0" encoding="UTF-8"?> <facelet...
Created by Fang on November 08, 2011 20:55:00    Last update: November 21, 2011 18:19:44
In the simple taglib example , I used a tag handler class to implement a taglib. This is an example to implement a taglib with a UI component. The purpose is to use a custom tag to split a string and print each part in a separate paragraph, i.e., print <p>john</p> <p>steve</p> <p>mike</p> with custom tag <my:foreach> : <my:foreach var="who" value="john steve mike"> ... These are the files: pom.xml <project xmlns="http://maven.apache.org/POM/4.0.0"... src/main/java/com/example/UIForeash.java : package com.example; import java.io.IOExcep... src/main/resources/META-INF/faces-config.xml : <?xml version="1.0" encoding="UTF-8"?> <faces-c... src/main/resources/META-INF/foreach.taglib.xml : <?xml version="1.0" encoding="UTF-8"?> <facelet... How to use: Put the JAR file generated by the above project in the WEB-INF/lib folder of the web app. If the web app is a Maven project, just add the taglib project as a dependency:...
Created by alfa on May 27, 2011 11:19:29    Last update: May 31, 2011 07:56:26
This is a utility to convert a string value to one of the primitive type values. It is useful in Java reflection code where the value comes in as a string (e.g., from XML parsing), and the type of the value cannot be decided until runtime. import java.util.*; import java.lang.reflect.*;... Note: This method can be extended to convert string to more complex types by writing a converter for the destination type. For example, to convert string to date: public class DateConverter { public static ... Usage: Date d = (Date) ConvertUtil.convert("10/12/2010", ...
Created by Dr. Xi on April 26, 2011 20:12:01    Last update: April 28, 2011 15:28:12
An XML schema is a definition of XML files, in XML. It plays the same role as old-time DTDs. Overall, an XML schema file looks like this: <schema attributeFormDefault = (qualified | u... The attribute meanings: targetNamespace : The name space targeted by the current schema definition. It can be any URI. id and version : For user convenience, the W3C spec defines no semantics for them. xml:lang : Natural language identifier defined by RFC 3306 . attributeFormDefault and elementFormDefault : Set default values for the form attribute for attribute and element declarations. blockDefault and finalDefault : Set default values for the block and final attributes for attribute and element declarations. The W3C defined some built-in datatypes . Examples of primitive datatypes are: string ,...
Created by Fang on August 10, 2010 21:37:36    Last update: October 25, 2010 20:18:47
The tags <fmt:formatNumber> Format a numeric value as number , currency or percentage - controlled by the type attribute (defaults to number if type is missing). Syntax: <fmt:formatNumber value="numericValue" [type="... Attributes: Name Dynamic? Type Description value true String or Number Numeric value to be formatted. type true String Specifies whether the value is to be formatted as number, currency, or percentage. pattern true String Custom formatting pattern, must follow the pattern syntax specified by the class java.text.DecimalFormat . currencyCode true String ISO 4217 currency code. Applied only when formatting currencies (i.e. if type is equal to "currency"); ignored otherwise. currencySymbol true String Currency symbol. Applied only when formatting currencies (i.e. if type is equal to "currency"); ignored otherwise. It is used only when currencyCode is...
Created by Fang on April 01, 2010 22:24:58    Last update: April 02, 2010 02:49:38
In this note I'll show you how to create and package a JSP custom tag. The purpose of this tag is to display a random splash image for a home page, among a set of images. We should be able to add or delete candidate splash images from the WAR archive without the need to change the JSP. This is the intended use of the tag: <%@ taglib uri="http://custom.tag.com/demo" prefix... In the above example you provide a set of images named splash*.png (e.g., splash1.png, spalsh2.png, ...), and the tag will pick a random one to display when the JSP is rendered. Let's get started. I'll use Maven for this purpose. Create the standard Maven directory structure ./pom.xml ./src ./src/main ./src/main/jav... pom.xml <project xmlns="http://maven.apache.org/POM/4.0.0"... SplashTag.java package tagdemo; import java.util.ArrayList......
Created by Dr. Xi on December 12, 2007 20:30:01    Last update: December 12, 2007 20:32:23
This is a script to tail a log file through the web browser. It uses AJAX, apache web server, mod_python, UNIX utilities tail (requires the --lines switch) and wc . The log file may reside on the web server or any other host accessible from the web server through SSH. Although it's written in python, it should be easy to port to other languages such as Perl. Apache httpd.conf : LoadModule python_module modules/mod_python.so ... Python script: import time, os from os.path import basename ...