maven pom, scope

<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>

<!-- The Basics -->
<groupId>...</groupId>
<artifactId>...</artifactId>
<version>...</version>
<packaging>...</packaging>
<dependencies>...</dependencies>
<parent>...</parent>
<dependencyManagement>...</dependencyManagement>
<modules>...</modules>
<<b>properties</b>>...</properties>

<!-- Build Settings -->
<build>...</build>
<reporting>...</reporting>

<!-- More Project Information -->
<name>...</name>
<description>...</description>
<url>...</url>
<inceptionYear>...</inceptionYear>
<licenses>...</licenses>
<organization>...</organization>
<developers>...</developers>
<contributors>...</contributors>

<!-- Environment Settings -->
<issueManagement>...</issueManagement>
<ciManagement>...</ciManagement>
<mailingLists>...</mailingLists>
<scm>...</scm>
<prerequisites>...</prerequisites>
<repositories>...</repositories>
<pluginRepositories>...</pluginRepositories>
<distributionManagement>...</distributionManagement>
<profiles>...</profiles>
</project>

scope:

• compile - default used if none is specified. Compile dependencies are available in all classpaths. Furthermore, those dependencies are propagated to dependent projects.
• provided - this is much like compile, but indicates you expect the JDK or a container to provide it at runtime. It is only available on the compilation and test classpath, and is not transitive.
• runtime - this scope indicates that the dependency is not required for compilation, but is for execution. It is in the runtime and test classpaths, but not the compile classpath.
• test - this scope indicates that the dependency is not required for normal use of the application, and is only available for the test compilation and execution phases.
• system - this scope is similar to provided except that you have to provide the JAR which contains it explicitly. The artifact is always available and is not looked up in a repository.

maven release plugin

mvn release:prepare

Preparing a release goes through the following release phases:

• Check that there are no uncommitted changes in the sources
• Check that there are no SNAPSHOT dependencies
• Change the version in the POMs from x-SNAPSHOT to a new version (you will be prompted for the versions to use)
• Transform the SCM information in the POM to include the final destination of the tag
• Run the project tests against the modified POMs to confirm everything is in working order
• Commit the modified POMs
• Tag the code in the SCM with a version name (this will be prompted for)
• Bump the version in the POMs to a new value y-SNAPSHOT (these values will also be prompted for)
• Commit the modified POMs

scm URL will be taken from <scm> or <meta http-equiv="content-type" content="text/html; charset=utf-8">-DconnectionUrl<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: 'Times New Roman'; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; font-size: medium;"><span class="Apple-style-span" style="font-family: Verdana,Helvetica,Arial,sans-serif; font-size: 16px;"></span></span>
<b>mvn release:</b><b>perform</b>

Performing a release runs the following release phases:

• Checkout from an SCM URL with optional tag
• Run the predefined Maven goals to release the project (by default, deploy site-deploy

Non-interactive

mvn --batch-mode -<i>Dtag</i>=my-proj-1.2 <b>release:prepare</b> \<br />                 -<i>DreleaseVersion</i>=1.2 \<br />                 -<i>DdevelopmentVersion</i>=2.0-SNAPSHOT

** There properties can be inside release.properties file

Cleaning
mvn release:clean - for cleaning resourced created by prepare
mvn release:rollback - for half done

Additional goals and release goals

<configuration>  <preparationGoals>clean install verify</preparationGoals>  <goals>deploy</goals><br /></configuration>

update version of all projects

mvn release:<i><b>update-versions</b></i> -DautoVersionSubmodules=true

release sequence policy and deprecation

Major
Upgrading between major versions will most likely require some data migration and is to be regarded as a major event.
Minor
Will contain feature enhancements. A bigger test cycle of custom code and templates will be required.
Maintenance
Upgrading between maintenance releases should not require a big test cycle. A maintenance release should only contain bug fixes and no changed or added functionality.

As long as you have not used a bug or an undocumented feature as a significant feature in custom extensions, you should be fine in upgrading between maintenance releases.

Deprecation
A maintenance release might deprecate some API features. Deprecated features will not actually be removed until the next major release.

A major release will never remove API features that have not been deprecated in a previous maintenance release.

A look at apache commons lang

ArrayUtils.reverse(starr);
CharUtils.isAsciiAlphaLower('s')
CharUtils.unicodeEscaped('&')
NumberUtils.min(intarr)
NumberUtils.max(intarr)
RandomStringUtils.randomAscii(8) + "\t" +
RandomStringUtils.randomAlphabetic(8) + "\t" +
RandomStringUtils.randomAlphanumeric(8) + "\t" +
RandomStringUtils.randomNumeric(8) + "\t"
RandomStringUtils.random(8, "0123456789ABCDEF")
StringEscapeUtils.escapeHtml("<html><html/>")
StringEscapeUtils.escapeXml("<xml/>")
"name='" + StringEscapeUtils.escapeSql("Peter's store") +"'"
StringEscapeUtils.unescapeHtml("&lt;html&gt;&lt;html/&gt;")
StringUtils.isNumeric("nto")
StringUtils.abbreviate("Apache Commons Lang", 10)
StringUtils.getLevenshteinDistance("Nahian", "nahin")
StringUtils.left("Nahian", 3)
StringUtils.right("Nahian", 3)
StringUtils.leftPad("Nahian", 10)
SystemUtils.IS_OS_UNIX
SystemUtils.getJavaHome()
SystemUtils.getUserDir()
SystemUtils.getUserHome()
SystemUtils.JAVA_VERSION
SystemUtils.JAVA_RUNTIME_NAME
SystemUtils.OS_ARCH + " : " + SystemUtils.OS_NAME + " : " + SystemUtils.OS_VERSION
SystemUtils.USER_COUNTRY + " : " + SystemUtils.USER_LANGUAGE
WordUtils.initials("Apache Commons Lang.Co", new char[] {' ', '.'})
WordUtils.capitalize("This is the title of the sectionn")

Need a closer look at ArrayUtils, DateUtils, DateFormatUtils

maven pmd plugin and cpd

$ mvn jxr:jxr pmd:pmd pmd:cpd

configuration:
  <reporting>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-pmd-plugin</artifactId>
        <version>2.3</version>
        <configuration>
          <!-- to link to the output of jxr -->
          <linkXref>true</linkXref>
          <!-- if this is the root project -->
          <aggregate>true</aggregate>
          <!-- minimum token to detect duplicate -->
          <minimumTokens>100</minimumTokens>
          <targetJdk>1.5</targetJdk>
          <excludes>
            <exclude>**/*Bean.java</exclude>
          </excludes>
          <excludeRoots>
            <excludeRoot>the_source_dir_to_exclude</excludeRoot>
          </excludeRoots>
        </configuration>
      </plugin>
    </plugins>
  </reporting>

Jtidy

- DOM parser
 : Node node = tidy.parser(IS/reader, OS/writer);
- pretty printer
 : tidy.pprint(dom_Doc/node, OS)
- HTML cleaner, makes well formed HTML

CONFIGURATION
    // make well formed
    tidy.setXHTML(true);
    tidy.setHideComments(true);
    tidy.setIndentContent(true);
    // space for indentation
    tidy.setSpaces(4);
    // whether to add tidy meta content tag
    tidy.setTidyMark(false);

    if (ERROR_PRINT_MODE)
      tidy.setOnlyErrors(true);
    else
      tidy.setQuiet(true);

Other config
    // tidy.setShowWarnings(false);
    //  tidy.setErrout(new PrintWriter(new StringWriter()));
    // shows only <body> tag
    // tidy.setPrintBodyOnly(true);

substring using awk

$ echo "jtidy-r938-sources.jar" | awk '{i=index($0,".jar");print substr($0,1,i-1)}'
> jtidy-r938-sources

AWK basics

command: awk 'pattern {expression} [; ptrn {exp}]'
default-pattern: 1
default expression: print
hence,
  '1' ~ '{print}' ~ '{print $0}' ~ '1 {print $0}

patterns:
BEGIN at file begin
END at file end
/match-pattern/ for string matching

Default vars:
NF: nOf fields
NR: nOf record so far
FNR: file's nOf record so far
length(): nOf letters
FS & OFS: field separator
RS & ORS: record separator
FILENAME


c-like code:

'{ s = 0; for (i = 1; i <= NF; i++) s = s+$i; print s }'

'{ printf("%5d : %s\n", NR, $0) }' 

for(i=1;i<=NF;i++) if($i~/[0-9]+/) $i=""; 

String utility:
substitute: '{ sub(/pattern/, "replacement'); print }'
or gsub for substitute all

shell $ variable

# ./getlyrics dhur valo "lage na"
 $1: dhur
 $3: lage na
 $#: 3
 $0: ./getlyrics
 $@: dhur valo lage na
 $*: dhur valo lage na

maven-jxr-plugin

- can generate HTML pages with project source
mvn jxr:jxr
- can generate HTML pages with project test source
mvn jxr:test-jxr
- can link the source HTML file with Javadoc if configured

How Pingback work

First = receptor
Second = originator<br><br />Pingback:
-> First blog exposes a ping back server
X-Pingback header or,
<link rel="pingback" href="([^"]+)" ?/?>

-> Second blog put a <a href> to First blog
-> Second pingback client will discover First pingback server from HTTP header or <link>
-> Second pingback client sends a xml-rpc request to First server with:
 method: pingback.ping
 param: sourceURI, targetURI

-> First pingback server now can do anything
 . check whether targetURI exits?
 . check whether srouceURI exits and has the link
 . record the pingback
 . change model so site page contains a link to source URI

Refback:
Nothing special required at Second end.
When browser loads url from First blog URL, it sends 'Referer' header with value Second blog URL

Trackback:
-> Trackback URI is RESTful .

-> service discovery with RDF xml

System boot and linux boot

System boot
BIOS - checks memory and runs MBR
MBR - checks partition table and loads BootLoader(grub)
BootLoader - on OS selection, loads kernel
kernel starts the init process
// now booting is done

RUN LEVEL
0 - system halt(shutdown)
1 - single user
2-5 - multi-user
6 - restart
S - transitional run level

$ runlevel

Typical sysvinit startup
$ /etc/init.d/rc RL
runs the srcitsp in /etc/rc$RL.d
this is how sysvinit init worked

How upstart works
upstart jobs are defined in /etc/init/*.conf
hence, /etc/init/rc.conf loads /etc/init.d/rc $RL this way sysvinit functionality served.
Technorati Tags: linux

Create a upstart Task(9.10)

JOB
 -> Task ( ends by themeselves)
 -> Services (supervised by init)

http://www.linux.com/archive/feature/125977

$vim /etc/init/fun.conf
start on dofun
#stop on runlevel 016[]
script
        echo "i am having fine now:" >> /tmp/funny.txt
        echo `date` >> /tmp/funnyt.txt
end script

$ initctl emit dofun

other use of initctl for upstart init daemon
$initctl list
$initctl start/stop/status/restart/reload
Technorati Tags: linux, ubuntu, daemon

using xmms2

run xmms2 server
$ xmms2-launcher

play songs
$ xmms2 add FILE
$ xmms2 radd DIR
$ xmms2 play/stop/pause/list/status

media library
$ xmms2 mlib addpath PATH
$ xmms2 mlib search artist:"SDFSDFSF"
$ xmms2 mlib searchadd
$ xmms2 mlib loadall

maven enforcer plugin

Checking a system property

        <executions>
          <execution>
            <id>enforce-property</id>
            <goals>
              <goal>enforce</goal>
            </goals>            
            <phase>compile</phase>            
          </execution>
        </executions>
        <configuration>
          <rules>
            <<b>requireProperty</b>>
              <property>java7.home</property>
              <message>"You must set a property java7.home!"</message>                  
            </requireProperty>
          </rules>
        </configuration>

more rules

• bannedDependencies - enforces that excluded dependencies aren't included.
• evaluateBeanshell - evaluates a beanshell script.
• requireReleaseDeps - enforces that no snapshots are included as dependencies.
• requireMavenVersion - enforces the Maven version.
• requireJavaVersion - enforces the JDK version.
• requireProperty - enforces the existence and values of properties.
• requireFilesExist - enforces that the list of files do exist.

maven create mojo

- Create mojo class with inheritance and annotation
  /**
   * @goal release
   * @aggregator
   */
  public class ReleaseMojo extends AbstractReleaseMojo {
- annotation for defining mojotype: @aggregator
- annotated configuration parameters: @parameter
- parameters can be: single valued, multi-valued(array), collection of items, collection of objects, map, Object
- getLog() gives maven logging functions.
- maven project and its configuration from pom.xml can be used by annotation
    /**
     * @parameter default-value="${project}"
     * @required
     */
     protected MavenProject mExecutionProject;

http://maven.apache.org/guides/plugin/guide-java-plugin-development.html
http://maven.apache.org/developers/mojo-api-specification.html#The_Descriptor_and_Annotations
http://maven.apache.org/ref/2.2.1/maven-plugin-api/apidocs/org/apache/maven/plugin/AbstractMojo.html

maven inheritence, aggregator project

Aggregation

<project ..>
  <...>
  <modules>
    <module>my-project</module>
    <module>another-project</module>
  </modules>
</project>

Inhertence

<project ...><br />  <...><br />  <parent><br />    <groupId>org.codehaus.mojo</groupId><br />    <artifactId>my-parent</artifactId><br />    <version>2.0</version><br />    <relativePath>../my-parent</relativePath><br />  </parent><br /><br />  <artifactId>my-project</artifactId><br /></project><br />

A POM project may be inherited from - but does not necessarily have - any modules that it aggregates. Conversely, a POM project may aggregate projects that do not inherit from it.

spell checking in command line

 cat /tmp/nothing.txt | aspell -a

Yahoo openID discovery

Yadis Location
http://yahoo.com

XRDS Location
http://open.login.yahooapis.com/openid20/www.yahoo.com/xrds

OpenId provider server/endpoint discovery

OpenID 2.0 discovery
- XRI disovery -> resolve XRDS doc from XRI
- Yadis discovery
 > "X-XRDS-Location" header or meta-attibute
 > return XRDS document when "Get" with a header "Accept:application/xrds+xml"
- HTML based discovery
 > link to endpoint with rel="openid.server" or rel="openid.provider "

xrds document from google OpenID

- says which protocol are supported. Bolds are openId and openId attribute extension
- points to the OP endpoint

 
 
  http://specs.openid.net/auth/2.0/server
  http://openid.net/srv/ax/1.0
  http://specs.openid.net/extensions/ui/1.0/mode/popup
  http://specs.openid.net/extensions/ui/1.0/icon
  http://specs.openid.net/extensions/pape/1.0
  https://www.google.com/accounts/o8/ud 

And for livejournal (openID 1.0)
        http://openid.net/signon/1.0
        http://www.livejournal.com/openid/server.bml

Servlet and Filter pluggability from servlet 3.0

public class MyListener implements ServletContextListener{
    public void contextInitialized(ServletContextEvent sce) {
        ServletContext sc = sce.getServletContext();
        sc.addServlet("myServlet", "Sample servlet", "foo.bar.MyServlet",
                        null, -1);
        sc.addServletMapping("myServlet", new String[] {"/urlpattern/*"});
        sc.addFilter("myFilter", "Sample Filter", "foo.bar.MyFilter",
                        null);
        sc.addFilterMapping("myFilter", new String[] {"/urlpattern/*"},
                        “myServlet”, DispatcherType.REQUEST, false);
    }
}

Whats new in Servlet 2.4 & 2.5

Servlet 2.4
-- ServletRequest -> get Local/Remote host port ()
- <dispatcher> inside <filter-mapping>, so it helps decide when apply filter? Whether in case of direct request or forward or both?
- ServletRequestListener, ServletRequestAttibuteListener added with other listner clases for Session and Context(2.3)
-- servlet welcome files

Servlet 2.5
-- wildcard(*) matching for <servlet-name> in <filter-mapping>. So can apply a filter for all servlets.
-- multiple <servlet-name> in <filter-mapping>
-- multiple <url-patter> in <filter-mapping> and <servlet-mapping>
- annotation?? whatever

Listed in detail:
http://www.roseindia.net/servlets/DifferenceBetweenServlet2.5AndServlet2.4.shtml

http://www.javaworld.com/javaworld/jw-03-2003/jw-0328-servlet.html
http://www.javaworld.com/javaworld/jw-01-2006/jw-0102-servlet.html

Enable utf-8 for all JSP's

Don't have to put pageEncoding="utf-8" in all JSP pages

  <jsp-config>
    <jsp-property-group>
      <url-pattern>*.jsp</url-pattern>
      <page-encoding>utf-8</page-encoding>
      <!-- This works only on Servlet 2.5+ compatible servlet containers
         (like Tomcat 6.x, Resin 3.1+) -->
      <trim-directive-whitespaces>true</trim-directive-whitespaces>
    </jsp-property-group>
  </jsp-config>