To implement a JSP custom tag with dynamic attributes (for example, to pass-thru arbitrary attributes not handled by the JSP tag): Set the dynamic-attributes element to true in the TLD: <tag> <name>mark</name> <tag-class>c... The tag handler must implement javax.servlet.jsp.tagext.DynamicAttributes : package com.example.jsp; import java.io.*; ...

This code snippet gets the default keystore used by the Java keytool and displays the list of aliases along with the key type (certificate or private key). import java.io.File; import java.io.FileInputSt... The default keystore used by the above code is: $HOME/.keystore .

This is the command to print all regular files in the src folder but excluding all files within the .svn folders: $ find src -name .svn -prune -o -type f -print where -o is the or operator. Define a shortcut: ff () { find $1 -name .svn -prune -o -...

The C shell allows you to define aliases with arguments: \!^ passes the first argument, \!* passes all arguments. Examples from http://unixhelp.ed.ac.uk : alias print 'lpr \!^ -Pps5' alias print 'lp... In ksh or bash you cannot define alias with arguments. Use function instead.

Install usb.essentials . Package usbutils is optional. # opkg update # opkg install kmod-usb2 # opk... Install usb printer support: # opkg install kmod-usb-printer Install p910nd print server: # opkg install p910nd Edit /etc/config/p910nd : config p910nd option device /dev... Configure firewall to allow port 9100 ( /etc/config/firewall ): # Allow printer con... If clients are connecting from wan then the first line should be: option src wan Enable automatic start of print server when router boots: #/etc/init.d/p910nd enable Restart router: # reboot

This facelet fragment will never print anything: <ui:repeat var="person" value="#{myBean.theJTeam}"... because the test condition always returns false, even though the person var is not null. The same happens even when I define another variable with ui:param : <ui:repeat var="person" value="#{myBean.theJTeam}"... What's happening? The c:if test condition is evaluated before the ui:repeat tag had a chance to set the value! Both facelet ui tags and JSTL c tags are evaluated at the Render Response phase of the JSF lifecycle. But within the Render Response cycle, there are two sub-phases (so to speak): the first builds the UI element tree, the second renders the UI tree. The JSTL c:if tag is evaluated when the tree is built, but the facelet ui:repeat tag is evaluated when the UI...

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:...

In the test for the simple taglib example , I used a literal string for the name attribute: <my:hello name="Jack"/> What happens if the name attribute contains EL expresson? For example: <my:hello name="#{param['name']}"/> If EL works, the tag should take the value of the " name " request parameter and print it out. But the tag as implemented in the simple taglib example prints the literal string: Hello #{param['name']}! I am FaceletTag. In order to make a tag to recognize EL, we have to use TagAttribute.getValue(FaceletContext ctx) instead of TagAttribute.getValue() . The latter returns the literal value of the attribute. The HelloTagHandler should be changed to: package com.example; import java.io.IOExcep... Rebuild the taglib and test with a URL like this: http://localhost:8080/facelet-test/?name=Jack The tag will print:...

The HTML prettifier tidy can also be used to pretty print XML. Just use the -xml switch. tidy -xml <xmlfile> With indentation: tidy -xml -i <xmlfile> Increase indentation to 4 spaces from the default 2: tidy -xml -i --indent-spaces 4 <xmlfile>

Use tcpdump to monitor traffic on a network: To print all incoming and outgoing packets on host 192.168.0.1 : tcpdump host 192.168.0.1 To print all incoming and outgoing IP packets on host firebird : tcpdump ip host firebird To write raw packets to a file, rather than parsing and printing them out: tcpdump ip host firebird -w /tmp/firebird.pcap To listen on interface eth0 (without this, tcpdump listens on the lowest numbered, configured up interface except loopback): tcpdump -i eth0 ip Use switch -X for more verbose output: tcpdump -i eth0 ip -X host 192.168.0.1 Outgoing from 192.168.0.1 : tcpdump -i eth0 ip -X src host 192.168.0.1 Incoming to 192.168.0.1 : tcpdump -i eth0 ip -X dst host 192.168.0.1 More verbose output: tcpdump -i eth0 tcp -vvX host 192.168.0.1...