src/site/apt/comparison.apt

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 Comparison: Dependency vs Artifact vs MavenProject
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 Robert Scholte
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 2015-12-28
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Comparison: Dependency vs Artifact vs MavenProject

  Here's a small matrix which should help you choosing the right instance.

  In general:

  * an Artifact holds a file mapped on a certain coordinate (GAV + classifier + extension),

  * a {{{/ref/current/maven-model/maven.html#class_dependency}Dependency}} contains an artifact and has transitive information,

  * a MavenProject holds a pom-file, an optional main file derived from the packaging, and can have attached files (= with classifier and extension), all using the same GAV.

  []

*--------------------+-------------+----------------+---------------+
||                   || Dependency || Artifact      || MavenProject ||
*--------------------+-------------+----------------+---------------+
| Has dependencies   | yes         | no             | yes           |
*--------------------+-------------+----------------+---------------+
| filetype reference | {{{/ref/current/maven-core/artifact-handlers.html}type}} | file extension | packaging     |
*--------------------+-------------+----------------+---------------+
| version ranges     | yes         | no             | no            |
*--------------------+-------------+----------------+---------------+
| scope              | yes         | no             | no            |
*--------------------+-------------+----------------+---------------+
| attached artifacts | no          | no             | yes           |
*--------------------+-------------+----------------+---------------+

  This implies the following:

  * From dependency to artifact is possible, since you can map a type to an extension (see {{{/ref/current/maven-core/artifact-handlers.html}default dependency types}}).
    However, it is not possible to go from artifact back to dependency, there are several types which have jar as file extension for example.

  * There's no such thing as transitive artifacts. Filtering during resolution is based on DependencyFilters,
    ArtifactFilters can only be applied afterwards, hence are less powerful.

  []

  Notice that for historical reasons, Maven internal {{{/ref/current/maven-artifact/apidocs/org/apache/maven/artifact/Artifact.html}Artifact API}}
  mixes dependency and artifact concepts.