Sunday, February 9, 2014

Introduction to the Build Lifecycle

Build Lifecycle Basics

Maven 2.0 is based around the central concept of a build lifecycle. What this means is that the process for building and distributing a particular artifact (project) is clearly defined.
For the person building a project, this means that it is only necessary to learn a small set of commands to build any Maven project, and the POM will ensure they get the results they desired.
There are three built-in build lifecycles: default, clean and site. The default lifecycle handles your project deployment, the clean lifecycle handles project cleaning, while the site lifecycle handles the creation of your project's site documentation.

A Build Lifecycle is Made Up of Phases

Each of these build lifecycles is defined by a different list of build phases, wherein a build phase represents a stage in the lifecycle.
For example, the default lifecycle has the following build phases (for a complete list of the build phases, refer to the Lifecycle Reference):
  • validate - validate the project is correct and all necessary information is available
  • compile - compile the source code of the project
  • test - test the compiled source code using a suitable unit testing framework. These tests should not require the code be packaged or deployed
  • package - take the compiled code and package it in its distributable format, such as a JAR.
  • integration-test - process and deploy the package if necessary into an environment where integration tests can be run
  • verify - run any checks to verify the package is valid and meets quality criteria
  • install - install the package into the local repository, for use as a dependency in other projects locally
  • deploy - done in an integration or release environment, copies the final package to the remote repository for sharing with other developers and projects.
These build phases (plus the other build phases not shown here) are executed sequentially to complete the default lifecycle. Given the build phases above, this means that when the default lifecycle is used, Maven will first validate the project, then will try to compile the sources, run those against the tests, package the binaries (e.g. jar), run integration tests against that package, verify the package, install the verifed package to the local repository, then deploy the installed package in a specified environment.
To do all those, you only need to call the last build phase to be executed, in this case, deploy:
mvn deploy
That is because if you call a build phase, it will execute not only that build phase, but also every build phase prior to the called build phase. Thus, doing
mvn integration-test
will do every build phase before it (validatecompilepackage, etc.), before executing integration-test.
There are more commands that are part of the lifecycle, which will be discussed in the following sections.
It should also be noted that the same command can be used in a multi-module scenario (i.e. a project with one or more subprojects). For example:
mvn clean install
This command will traverse into all of the subprojects and run clean, then install (including all of the prior steps).

A Build Phase is Made Up of Plugin Goals

However, even though a build phase is responsible for a specific step in the build lifecycle, the manner in which it carries out those responsibilities may vary. And this is done by declaring the plugin goals bound to those build phases.
A plugin goal represents a specific task (finer than a build phase) which contributes to the building and managing of a project. It may be bound to zero or more build phases. A goal not bound to any build phase could be executed outside of the build lifecycle by direct invocation. The order of execution depends on the order in which the goal(s) and the build phase(s) are invoked. For example, consider the command below. The clean and package arguments are build phases, while the dependency:copy-dependencies is a goal (of a plugin).
mvn clean dependency:copy-dependencies package
If this were to be executed, the clean phase will be executed first (meaning it will run all preceeding phases of the clean lifecycle, plus the clean phase itself), and then thedependency:copy-dependencies goal, before finally executing the package phase (and all its preceeding build phases of the default lifecycle).
Moreover, if a goal is bound to one or more build phases, that goal will be called in all those phases.
Furthermore, a build phase can also have zero or more goals bound to it. If a build phase has no goals bound to it, that build phase will not execute. But if it has one or more goals bound to it, it will execute all those goals (Note: In Maven 2.0.5 and above, multiple goals bound to a phase are executed in the same order as they are declared in the POM, however multiple instances of the same plugin are not supported. Multiple instances of the same plugin are grouped to execute together and ordered in Maven 2.0.11 and above).

Setting Up Your Project to Use the Build Lifecycle

The build lifecycle is simple enough to use, but when you are constructing a Maven build for a project, how do you go about assigning tasks to each of those build phases?

Packaging

The first, and most common way, is to set the packaging for your project via the equally named POM element . Some of the valid packaging values are jarwarearand pom. If no packaging value has been specified, it will default to jar.
Each packaging contains a list of goals to bind to a particular phase. For example, the jar packaging will bind the following goals to build phases of the default lifecycle.
process-resourcesresources:resources
compilecompiler:compile
process-test-resourcesresources:testResources
test-compilecompiler:testCompile
testsurefire:test
packagejar:jar
installinstall:install
deploydeploy:deploy
This is an almost standard set of bindings; however, some packagings handle them differently. For example, a project that is purely metadata (packaging value is pom) only binds goals to the install and deploy phases (for a complete list of goal-to-build-phase bindings of some of the packaging types, refer to the Lifecycle Reference).
Note that for some packaging types to be available, you may also need to include a particular plugin in the  section of your POM and specifytrue for that plugin. One example of a plugin that requires this is the Plexus plugin, which provides a plexus-application and plexus-servicepackaging.

Plugins

The second way to add goals to phases is to configure plugins in your project. Plugins are artifacts that provide goals to Maven. Furthermore, a plugin may have one or more goals wherein each goal represents a capability of that plugin. For example, the Compiler plugin has two goals: compile and testCompile. The former compiles the source code of your main code, while the latter compiles the source code of your test code.
As you will see in the later sections, plugins can contain information that indicates which lifecycle phase to bind a goal to. Note that adding the plugin on its own is not enough information - you must also specify the goals you want to run as part of your build.
The goals that are configured will be added to the goals already bound to the lifecycle from the packaging selected. If more than one goal is bound to a particular phase, the order used is that those from the packaging are executed first, followed by those configured in the POM. Note that you can use the  element to gain more control over the order of particular goals.
For example, the Modello plugin binds by default its goal modello:java to the generate-sources phase (Note: The modello:java goal generates Java source codes). So to use the Modello plugin and have it generate sources from a model and incorporate that into the build, you would add the following to your POM in the  section of :
...
 
   org.codehaus.modello
   modello-maven-plugin
   1.4
   
     
       
         
           src/main/mdo/maven.mdo
         
         4.0.0
       
       
         java
       
     
   
 
...
You might be wondering why that  element is there. That is so that you can run the same goal multiple times with different configuration if needed. Separate executions can also be given an ID so that during inheritance or the application of profiles you can control whether goal configuration is merged or turned into an additional execution.
When multiple executions are given that match a particular phase, they are executed in the order specified in the POM, with inherited executions running first.
Now, in the case of modello:java, it only makes sense in the generate-sources phase. But some goals can be used in more than one phase, and there may not be a sensible default. For those, you can specify the phase yourself. For example, let's say you have a goal display:time that echos the current time to the commandline, and you want it to run in the process-test-resources phase to indicate when the tests were started. This would be configured like so:
...
 
   com.mycompany.example
   display-maven-plugin
   1.0
   
     
       process-test-resources
       
         time
       
     
   
 
...

Lifecycle Reference

The following lists all build phases of the default, clean and site lifecycle, which are executed in the order given up to the point of the one specified.
Clean Lifecycle
pre-cleanexecutes processes needed prior to the actual project cleaning
cleanremove all files generated by the previous build
post-cleanexecutes processes needed to finalize the project cleaning
Default Lifecycle
validatevalidate the project is correct and all necessary information is available.
initializeinitialize build state, e.g. set properties or create directories.
generate-sourcesgenerate any source code for inclusion in compilation.
process-sourcesprocess the source code, for example to filter any values.
generate-resourcesgenerate resources for inclusion in the package.
process-resourcescopy and process the resources into the destination directory, ready for packaging.
compilecompile the source code of the project.
process-classespost-process the generated files from compilation, for example to do bytecode enhancement on Java classes.
generate-test-sourcesgenerate any test source code for inclusion in compilation.
process-test-sourcesprocess the test source code, for example to filter any values.
generate-test-resourcescreate resources for testing.
process-test-resourcescopy and process the resources into the test destination directory.
test-compilecompile the test source code into the test destination directory
process-test-classespost-process the generated files from test compilation, for example to do bytecode enhancement on Java classes. For Maven 2.0.5 and above.
testrun tests using a suitable unit testing framework. These tests should not require the code be packaged or deployed.
prepare-packageperform any operations necessary to prepare a package before the actual packaging. This often results in an unpacked, processed version of the package. (Maven 2.1 and above)
packagetake the compiled code and package it in its distributable format, such as a JAR.
pre-integration-testperform actions required before integration tests are executed. This may involve things such as setting up the required environment.
integration-testprocess and deploy the package if necessary into an environment where integration tests can be run.
post-integration-testperform actions required after integration tests have been executed. This may including cleaning up the environment.
verifyrun any checks to verify the package is valid and meets quality criteria.
installinstall the package into the local repository, for use as a dependency in other projects locally.
deploydone in an integration or release environment, copies the final package to the remote repository for sharing with other developers and projects.
Site Lifecycle
pre-siteexecutes processes needed prior to the actual project site generation
sitegenerates the project's site documentation
post-siteexecutes processes needed to finalize the site generation, and to prepare for site deployment
site-deploydeploys the generated site documentation to the specified web server

Built-in Lifecycle Bindings

Some phases have goals bound to them by default. And for the default lifecycle, these bindings depend on the packaging value. Here are some of the goal-to-build-phase bindings.

Clean Lifecycle Bindings

cleanclean:clean

Default Lifecycle Bindings - Packaging ejb / ejb3 / jar / par / rar / war

process-resourcesresources:resources
compilecompiler:compile
process-test-resourcesresources:testResources
test-compilecompiler:testCompile
testsurefire:test
packageejb:ejb or ejb3:ejb3 or jar:jar or par:par or rar:rar or war:war
installinstall:install
deploydeploy:deploy

Default Lifecycle Bindings - Packaging ear

generate-resourcesear:generate-application-xml
process-resourcesresources:resources
packageear:ear
installinstall:install
deploydeploy:deploy

Default Lifecycle Bindings - Packaging maven-plugin

generate-resourcesplugin:descriptor
process-resourcesresources:resources
compilecompiler:compile
process-test-resourcesresources:testResources
test-compilecompiler:testCompile
testsurefire:test
packagejar:jar and plugin:addPluginArtifactMetadata
installinstall:install
deploydeploy:deploy

Default Lifecycle Bindings - Packaging pom

packagesite:attach-descriptor
installinstall:install
deploydeploy:deploy

Site Lifecycle Bindings

sitesite:site
site-deploysite:deploy

References

The full Maven lifecycle is defined by the file components.xml in the module maven-core and viewable from SVN in the branch for Maven 2.2.1 and Git for Maven 3.x.
In Maven 2.x, default lifecycle bindings were included in components.xml, but in Maven 3.x, they are defined in a separate default-bindings.xml descriptor.
See Lifecycles Reference and Plugin Bindings for default Lifecycle Reference for latest documentation taken directly from source code.

9 comments:

oakleyses said...

louis vuitton handbags, oakley sunglasses, louboutin, longchamp outlet, nike shoes, louis vuitton outlet stores, chanel handbags, burberry outlet, prada outlet, jordan shoes, tiffany and co, michael kors outlet, tory burch outlet, louis vuitton outlet, longchamp handbags, nike free, true religion jeans, michael kors outlet, kate spade outlet, polo ralph lauren outlet, tiffany and co, prada handbags, polo ralph lauren outlet, michael kors outlet, michael kors outlet, longchamp handbags, oakley sunglasses, ray ban sunglasses, kate spade handbags, burberry outlet, louis vuitton outlet, louboutin outlet, louboutin, coach factory outlet, air max, air max, coach outlet, gucci outlet, christian louboutin shoes, michael kors outlet, coach purses, ray ban sunglasses, michael kors outlet, louis vuitton, coach outlet store online, true religion jeans, oakley sunglasses cheap

oakleyses said...

ralph lauren, lululemon, air max, hollister, north face, nike air max, polo lacoste, vanessa bruno, timberland, vans pas cher, louboutin, louis vuitton, oakley pas cher, air max pas cher, nike roshe run, air max, true religion outlet, barbour, sac longchamp, air force, hollister, sac louis vuitton, nike free, polo ralph lauren, nike trainers, louis vuitton uk, nike roshe, sac hermes, longchamp, michael kors, sac burberry, sac guess, mulberry, new balance pas cher, converse pas cher, sac louis vuitton, hogan outlet, nike tn, north face, true religion outlet, ray ban pas cher, michael kors, air jordan, nike blazer, nike free pas cher, michael kors pas cher, abercrombie and fitch, ray ban sunglasses

oakleyses said...

mac cosmetics, mont blanc, marc jacobs, canada goose outlet, nike huarache, vans shoes, soccer jerseys, hollister, giuseppe zanotti, beats by dre, abercrombie and fitch, longchamp, insanity workout, celine handbags, bottega veneta, ghd, nfl jerseys, north face outlet, chi flat iron, ugg boots, birkin bag, ugg australia, canada goose, herve leger, ugg pas cher, rolex watches, valentino shoes, canada goose uk, canada goose, ferragamo shoes, canada goose, ugg boots, uggs outlet, north face jackets, soccer shoes, asics running shoes, new balance shoes, p90x, lululemon outlet, canada goose jackets, mcm handbags, instyler, babyliss pro, ugg, wedding dresses, jimmy choo outlet, reebok outlet, nike roshe run

oakleyses said...

parajumpers, karen millen, air max, converse, pandora charms, moncler, louboutin, moncler, links of london, lancel, juicy couture outlet, oakley, hollister, pandora charms, supra shoes, thomas sabo, canada goose, gucci, wedding dresses, timberland boots, swarovski crystal, air max, coach outlet store online, moncler, ray ban, canada goose, moncler, ugg, louis vuitton, swarovski, hollister, montre homme, moncler, hollister clothing store, ralph lauren, rolex watches, moncler outlet, moncler, iphone 6 cases, baseball bats, juicy couture outlet, toms shoes, vans, pandora jewelry, ugg, converse shoes

oakleyses said...

jordan pas cher, chanel handbags, nike outlet, michael kors pas cher, kate spade outlet, replica watches, longchamp pas cher, nike free, jordan shoes, christian louboutin shoes, nike free run, louis vuitton outlet, oakley sunglasses, ray ban sunglasses, polo ralph lauren, ugg boots, christian louboutin uk, air max, louis vuitton outlet, ugg boots, tiffany jewelry, polo ralph lauren outlet online, burberry pas cher, prada outlet, nike air max, gucci handbags, sac longchamp pas cher, ray ban sunglasses, louboutin pas cher, louis vuitton, uggs on sale, tiffany and co, oakley sunglasses, louis vuitton outlet, ray ban sunglasses, longchamp outlet, louis vuitton, longchamp outlet, replica watches, nike roshe, polo outlet, oakley sunglasses, cheap oakley sunglasses, oakley sunglasses wholesale, christian louboutin, christian louboutin outlet, tory burch outlet

oakleyses said...

lululemon canada, nike air max, burberry outlet, oakley pas cher, burberry handbags, coach outlet store online, kate spade, michael kors outlet, michael kors, nike air force, true religion jeans, true religion outlet, michael kors, polo lacoste, nike tn, new balance, abercrombie and fitch uk, michael kors outlet, uggs outlet, michael kors outlet, ralph lauren uk, michael kors outlet online, replica handbags, coach outlet, true religion outlet, coach purses, nike free uk, sac vanessa bruno, mulberry uk, michael kors outlet online, michael kors outlet online, michael kors outlet online, north face, uggs outlet, converse pas cher, hogan outlet, nike air max uk, hollister pas cher, sac hermes, nike roshe run uk, hollister uk, nike air max uk, true religion outlet, timberland pas cher, vans pas cher, ray ban pas cher, guess pas cher, ray ban uk

oakleyses said...

ipad cases, beats by dre, iphone 6 cases, ferragamo shoes, wedding dresses, hollister clothing, p90x workout, instyler, asics running shoes, nike huaraches, hermes belt, north face outlet, s6 case, babyliss, nfl jerseys, hollister, iphone 6 plus cases, insanity workout, ralph lauren, iphone cases, iphone 6s plus cases, bottega veneta, new balance shoes, longchamp uk, iphone 6s cases, giuseppe zanotti outlet, nike roshe run, mont blanc pens, herve leger, oakley, lululemon, timberland boots, nike air max, iphone 5s cases, ghd hair, valentino shoes, louboutin, nike trainers uk, celine handbags, north face outlet, baseball bats, vans outlet, abercrombie and fitch, chi flat iron, soccer jerseys, mac cosmetics, mcm handbags, soccer shoes, jimmy choo outlet, reebok outlet

oakleyses said...

supra shoes, marc jacobs, canada goose, converse outlet, toms shoes, ugg uk, ugg pas cher, canada goose outlet, canada goose, nike air max, louis vuitton, karen millen uk, doudoune moncler, converse, louis vuitton, vans, gucci, montre pas cher, moncler outlet, canada goose uk, canada goose outlet, moncler, pandora jewelry, barbour uk, moncler outlet, juicy couture outlet, louis vuitton, canada goose, pandora uk, coach outlet, swarovski crystal, ugg,uggs,uggs canada, juicy couture outlet, links of london, louis vuitton, louis vuitton, hollister, swarovski, canada goose outlet, ray ban, moncler, ugg, barbour, ugg,ugg australia,ugg italia, replica watches, pandora charms, moncler uk, pandora jewelry, wedding dresses, canada goose jackets, hollister, lancel

Mie Helal said...



I was excited to discover this website
http://www.kuwait.prokr.net/
http://www.emirates.prokr.net/