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Created by Fang on January 28, 2012 13:24:09    Last update: January 28, 2012 13:31:22
This is a simple JSP custom tags library with tag body. Just like the JSF counterpart , it splits a string and repeats the body for each word, i.e., with this markup: <%@ taglib uri="http://custom.tag.com/demo" prefix... output: <html> <body> <p>Hello Tigger!</p> <p>H... With Maven, this is the directory structure: ./src ./src/main ./src/main/resources ./s... There are three files to write: pom.xml : <project xmlns="http://maven.apache.org/POM/4.0.0"... src/main/java/tagdemo/IterateTag.java : package tagdemo; import java.io.IOException... src/main/resources/META-INF/demotag.tld : <?xml version="1.0" encoding="UTF-8"?> <!DO... Build with: mvn clean install To use it as a dependency in other Maven projects: <dependency> <groupId>tag-demo</groupId> ...
Created by lokf on January 13, 2012 14:10:42    Last update: January 13, 2012 14:10:42
For some reason I don't know writing to files in Android is very complicated and tedious. Here is some code for those who might need it. Apps should write in the SD in the directory /Android/data/package_name/files/ so that it is deleted with the app uninstall. package randomname; import java.io.BufferedOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.FileWriter; import java.io.IOException; import java.io.OutputStream; import java.io.OutputStreamWriter; import java.nio.ByteBuffer; import android.content.Context; import android.os.Environment; import android.util.Log; public class FileIOLibrary { String packageName; boolean mExternalStorageAvailable = false; boolean mExternalStorageWriteable = false; FileIOLibrary(String packageNamep) { this.packageName=packageNamep; } public boolean isExternalStorageAvailable() { updateExternalStorageState(); return mExternalStorageAvailable; } public boolean isExternalStorageWritable() { updateExternalStorageState(); return mExternalStorageWriteable; } /** * writes the current state of SD card to the corresponding variables */ void updateExternalStorageState() {...
Created by Fang on January 04, 2012 09:54:05    Last update: January 04, 2012 09:54:05
There are two ways to validate a form with JSF: jsf validation on the page with <f:validate...> tags (for example: <f:validateLength> , <f:validateRegex> , etc.), or JSR303 bean validation. This note is about how to customize messages for JSR303 bean validation. The validation message is specified in the message attribute for each validation annotation type. The mesage attribute is not a literal string, but a string that is interpolated in various ways. For example, the default validation message for AssertFalse is {javax.validation.constraints.AssertFalse.message} , which is replaced with the corresponding string in ValidationMessages.properties (or ValidationMessages_tr.properties , ValidationMessages_es.properties , depending on the locale). This is the contents of ValidationMessages.properties in the hibernate validator reference implementation: javax.validation.constraints.AssertFalse.message =... To customize the messages, just provide the new value in...
Created by Fang on November 28, 2011 21:04:15    Last update: November 28, 2011 21:04:15
Some innocent looking JavaScript may cause a fatal error in a Facelet page. For example: <script type="text/javascript"> if (items.lengt... or <script type="text/javascript"> // jQuery code ... Because Facelet is strict XML, therefore, < and > must be escaped. There are several ways to deal with this: Do not embed JS code directly in the page. Put the code in .js files and include it in the page with the src attribute. Put JS code in a CDATA section: <h:outputScript target="head"> <![CDATA... Use XML entities: <script type="text/javascript"> // jQuery code ...
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 Dr. Xi on November 11, 2011 10:05:22    Last update: November 11, 2011 10:12:01
This is an HTML image tag filter using Java regex. It takes a string, finds the img tags, replaces the src attribute with one provided by the filter, then adds a class name to the class attribute. import java.util.regex.*; import java.io.*; ... Test file: <div id="HTML snippet"> <img src="img/big/txt-m...
Created by magnum on September 27, 2011 13:57:23    Last update: October 03, 2011 13:02:34
After an IPSec connection is established, all traffic between the network interfaces named in /etc/ipsec.conf are tunneled through IPSec. And only the protocols and ports listed in /etc/ipsec.conf are allowed. For example, if you were able to ssh to the server, after IPSec connection ssh is no longer working if port 22 is not listed. Assume that you set up IPSec tunnel between the hosts 192.168.0.1 and 192.168.0.101 , these tests will show that the IPSec connection is successfully working. Before bringing up IPSec connection If IPSec connection is already established, bring it down: # ipsec auto --down TCP8080-PSK-CLIENT Monitor server port 8080 with tcpdump ( 192.168.0.1 ): # tcpdump -i eth0 port 8080 -X On server side ( 192.168.0.1 ), listen on port 8080:...
Created by Dr. Xi on September 30, 2011 15:34:47    Last update: September 30, 2011 15:34:47
A naive try would be something like this: $ nc -l 8082 | nc remote_host 80 Yes, it does forward the request from local port 8082 to remote_host:80 , but the response is dumped to stdout , not routed back to the client as expected. Using a named pipe makes it work: $ mkfifo backpipe $ nc -l 8082 0<backpipe | nc ... Use tee to get a glimpse of the response through the pipe (I wasn't able to find a way to dump the request): $ nc -k -l 8082 0<backpipe | nc localhost 80 | tee... The GNU netcat has a different syntax than the stock nc . It also supports different switches. To listen to port 1234: $ netcat -l -p 1234...
Created by magnum on September 24, 2011 13:14:37    Last update: September 28, 2011 18:08:35
There are two sides to an IP socket: the local side and the remote side: The getpeername function retrieves the peer address of the specified socket. #include <sys/socket.h> int getpeername(int soc... Example: struct sockaddr_in addr; socklen_t socklen = si... The getsockname function retrieves the locally-bound name of the specified socket. #include <sys/socket.h> int getsockname(int soc... Example: struct sockaddr_in addr; socklen_t socklen = si...
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