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~~ under the License.

-----

Introduction

-----

Hervé Boutemy

-----

2013-03-19

-----

Maven Model Builder

The effective model builder, with profile activation, inheritance, interpolation, ...

The main component is <<<ModelBuilder>>>

({{{./apidocs/org/apache/maven/model/building/ModelBuilder.html}javadoc}},

{{{./xref/org/apache/maven/model/building/ModelBuilder.html}source}}),

with its <<<DefaultModelBuilder>>> implementation

({{{./apidocs/org/apache/maven/model/building/DefaultModelBuilder.html}javadoc}},

{{{./xref/org/apache/maven/model/building/DefaultModelBuilder.html}source}})

that manages the steps sequence.

The sequence is divided into 2 phases:

* phase 1

** profile activation: see {{{./apidocs/org/apache/maven/model/profile/activation/package-summary.html}available activators}}.

Notice that model interpolation hasn't happened yet, then interpolation for file-based activation is limited to

<<<$\{basedir}>>> (since Maven 3), system properties and user properties

** raw model validation: <<<ModelValidator>>> ({{{./apidocs/org/apache/maven/model/validation/ModelValidator.html}javadoc}}),

with its <<<DefaultModelValidator>>> implementation

({{{./xref/org/apache/maven/model/validation/DefaultModelValidator.html}source}})

** model normalization - merge duplicates: <<<ModelNormalizer>>> ({{{./apidocs/org/apache/maven/model/normalization/ModelNormalizer.html}javadoc}}),

with its <<<DefaultModelNormalizer>>> implementation

({{{./xref/org/apache/maven/model/normalization/DefaultModelNormalizer.html}source}})

** profile injection: <<<ProfileInjector>>> ({{{./apidocs/org/apache/maven/model/profile/ProfileInjector.html}javadoc}}),

with its <<<DefaultProfileInjector>>> implementation

({{{./xref/org/apache/maven/model/profile/DefaultProfileInjector.html}source}})

** parent resolution until {{{./super-pom.html}super-pom}}

** inheritance assembly (see {{{./index.html#Inheritance_Assembly}below}})

** model interpolation (see {{{./index.html#Model_Interpolation}below}})

** url normalization: <<<UrlNormalizer>>> ({{{./apidocs/org/apache/maven/model/path/UrlNormalizer.html}javadoc}}),

with its <<<DefaultUrlNormalizer>>> implementation

({{{./xref/org/apache/maven/model/path/DefaultUrlNormalizer.html}source}})

[]

* phase 2, with optional plugin processing

** model path translation: <<<ModelPathTranslator>>> ({{{./apidocs/org/apache/maven/model/path/ModelPathTranslator.html}javadoc}}),

with its <<<DefaultModelPathTranslator>>> implementation

({{{./xref/org/apache/maven/model/path/DefaultModelPathTranslator.html}source}})

** plugin management injection: <<<PluginManagementInjector>>> ({{{./apidocs/org/apache/maven/model/management/PluginManagementInjector.html}javadoc}}),

with its <<<DefaultPluginManagementInjector>>> implementation

({{{./xref/org/apache/maven/model/management/DefaultPluginManagementInjector.html}source}})

** <(optional)> lifecycle bindings injection: <<<LifecycleBindingsInjector>>> ({{{./apidocs/org/apache/maven/model/plugin/LifecycleBindingsInjector.html}javadoc}}),

with its <<<DefaultLifecycleBindingsInjector>>> implementation in maven-core

({{{./maven-core/xref/org/apache/maven/model/plugin/DefaultLifecycleBindingsInjector.html}source}})

** dependency management import (for dependencies of type <<<pom>>> and scope <<<import>>> in the <<<\<dependencyManagement\>>>> section)

** dependency management injection: <<<DependencyManagementInjector>>> ({{{./apidocs/org/apache/maven/model/management/DependencyManagementInjector.html}javadoc}}),

with its <<<DefaultDependencyManagementInjector>>> implementation

({{{./xref/org/apache/maven/model/management/DefaultDependencyManagementInjector.html}source}})

** model normalization - inject default values: <<<ModelNormalizer>>> ({{{./apidocs/org/apache/maven/model/normalization/ModelNormalizer.html}javadoc}}),

with its <<<DefaultModelNormalizer>>> implementation

({{{./xref/org/apache/maven/model/normalization/DefaultModelNormalizer.html}source}})

** <(optional)> reports configuration: <<<ReportConfigurationExpander>>> ({{{./apidocs/org/apache/maven/model/plugin/ReportConfigurationExpander.html}javadoc}}),

with its <<<DefaultReportConfigurationExpander>>> implementation

({{{./xref/org/apache/maven/model/plugin/DefaultReportConfigurationExpander.html}source}})

** <(optional)> reports conversion to decoupled site plugin: <<<ReportingConverter>>> ({{{./apidocs/org/apache/maven/model/plugin/ReportingConverter.html}javadoc}}),

with its <<<DefaultReportingConverter>>> implementation

({{{./xref/org/apache/maven/model/plugin/DefaultReportingConverter.html}source}})

** <(optional)> plugins configuration: <<<PluginConfigurationExpander>>> ({{{./apidocs/org/apache/maven/model/plugin/PluginConfigurationExpander.html}javadoc}}),

with its <<<DefaultPluginConfigurationExpander>>> implementation

({{{./xref/org/apache/maven/model/plugin/DefaultPluginConfigurationExpander.html}source}})

** effective model validation: <<<ModelValidator>>> ({{{./apidocs/org/apache/maven/model/validation/ModelValidator.html}javadoc}}),

with its <<<DefaultModelValidator>>> implementation

({{{./xref/org/apache/maven/model/validation/DefaultModelValidator.html}source}})

[]

[]

* Inheritance Assembly

Inheritance Assembly consists in filling current model empty fields with values taken from parent model.

It is done in <<<InheritanceAssembler>>> ({{{./apidocs/org/apache/maven/model/inheritance/InheritanceAssembler.html}javadoc}}),

with its <<<DefaultInheritanceAssembler>>> implementation

({{{./xref/org/apache/maven/model/inheritance/DefaultInheritanceAssembler.html}source}}).

By default, every model field is inherited as-is from parent, with a few exceptions that are intentionally not inherited:

<<<modelVersion>>>, <<<artifactId>>>, <<<profiles>>> (injected in phase 1) and <<<prerequisites>>>.

Notice that the 5 URLs from the model (<<<project.url>>>, <<<project.scm.connection>>>, <<<project.scm.developerConnection>>>,

<<<project.scm.url>>> and <<<project.distributionManagement.site.url>>>) have a special inheritance handling:

** if not configured in current model, the inherited value is the parent's one with current artifact id appended,

** since Maven 3.5.0, if <<<project.directory>>> POM property value is defined, it is used instead of artifact id:

this permits default inheritance calculations when module directory name is not equal to artifact id. Notice that this

property is not inherited from a POM to its child: childs POM will use child artifact id if property is not

set.

** since Maven 3.6.1, inheritance can avoid appending any path to parent value by setting model attribute value to

<<<false>>> for each url:

<<<project/@child.project.url.inherit.append.path>>>,

<<<project/distributionManagement/site/@child.site.url.inherit.append.path>>>,

<<<project/scm/@child.scm.connection.inherit.append.path>>>,

<<<project/scm/@child.scm.developerConnection.inherit.append.path>>> and

<<<project/scm/@child.scm.url.inherit.append.path>>>.

[]

* Model Interpolation

Model Interpolation consists in replacing <<<$\{...\}>>> with calculated value. It is done in <<<StringSearchModelInterpolator>>>

({{{./apidocs/org/apache/maven/model/interpolation/StringSearchModelInterpolator.html}javadoc}},

{{{./xref/org/apache/maven/model/interpolation/StringSearchModelInterpolator.html}source}}).

Notice that model interpolation happens <after> profile activation, then profile activation doesn't benefit from every values:

interpolation for file-based activation is limited to <<<$\{basedir}>>> (which was introduced in Maven 3 and is not deprecated

in this context), system properties and user properties.

Values are evaluated in sequence from different syntaxes:

*----+------+------+

|| value || evaluation result || common examples ||

*----+------+------+

| <<<project.*>>>\

<<<pom.*>>> (<deprecated>)\

<<<*>>> (<deprecated>) | POM content (see {{{../maven-model/maven.html}POM reference}}) | <<<$\{project.version\}>>>\

| | <<<$\{project.build.finalName\}>>>\

| | <<<$\{project.artifactId\}>>>\

| | <<<$\{project.build.directory\}>>> |

*----+------+------+

| <<<project.basedir>>>\

<<<pom.basedir>>> (<deprecated>)\

<<<basedir>>> (<deprecated>) | the directory containing the <<<pom.xml>>> file | <<<$\{project.basedir\}>>> |

*----+------+------+

| <<<project.baseUri>>>\

<<<pom.baseUri>>> (<deprecated>) | the directory containing the <<<pom.xml>>> file as URI | <<<$\{project.baseUri\}>>> |

*----+------+------+

| <<<build.timestamp>>>\

<<<maven.build.timestamp>>> | the UTC timestamp of build start, in <<<yyyy-MM-dd'T'HH:mm:ss'Z'>>> default format, which can be overridden with <<<maven.build.timestamp.format>>> POM property | <<<$\{maven.build.timestamp\}>>> |

*----+------+------+

| <<<*>>> | user properties, set from CLI with <<<-Dproperty=value>>> | <<<$\{skipTests\}>>> |

*----+------+------+

| <<<*>>> | model properties, such as project properties set in the pom | <<<$\{any.key\}>>> |

*----+------+------+

| <<<maven.home>>> | The path to the current Maven home. | <<<$\{maven.home\}>>> |

*----+------+------+

| <<<maven.version>>> | The version number of the current Maven execution <(since 3.0.4)>. For example, "<<<3.0.5>>>". | <<<$\{maven.version\}>>> |

*----+------+------+

| <<<maven.build.version>>> | The full build version of the current Maven execution <(since 3.0.4)>. For example, "<<<Apache Maven 3.2.2 (r01de14724cdef164cd33c7c8c2fe155faf9602da; 2013-02-19T14:51:28+01:00)>>>". | <<<$\{maven.build.version\}>>> |

*----+------+------+

| <<<maven.repo.local>>> | The repository on the local machine Maven shall use to store installed and downloaded artifacts (POMs, JARs, etc). | <<<$\{user.home\}/.m2/repository>>> |

*----+------+------+

| <<<*>>> | Java system properties (see {{{https://docs.oracle.com/javase/8/docs/api/java/lang/System.html#getProperties()}JDK reference}}) | <<<$\{user.home\}>>>\

| | <<<$\{java.home\}>>> |

*----+------+------+

| <<<*>>> | User properties | <<<$\{foo\}>>> |

*----+------+------+

| <<<env.*>>>\

<<<*>>> | environment variables | <<<$\{env.PATH\}>>> |

*----+------+------+

| <<<settings.*>>> | Local user settings (see {{{../maven-settings/settings.html}settings reference}}) | <<<$\{settings.localRepository\}>>> |

*----+------+------+

** Notice

* after model interpolation, <<<$\{...\}>>> content can remain in the model that will be evaluated later

when setting plugin parameters. This happens in particular with <<<settings.*>>> values for

{{{../maven-settings/settings.html}Settings Model}},

* encoding configuration have been defined as POM properties looking like POM content but not added to POM model to maintain

compatibility with previous Maven versions:

* <<<$\{project.build.sourceEncoding\}>>> for

{{{https://cwiki.apache.org/confluence/display/MAVEN/POM+Element+for+Source+File+Encoding}source files encoding}}

(defaults to platform encoding)

* <<<$\{project.reporting.outputEncoding\}>>> for

{{{https://cwiki.apache.org/confluence/display/MAVENOLD/Reporting+Encoding+Configuration}reporting output files encoding}}

(defaults to <<<UTF-8>>>)

[]

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