Author: jvanzyl
Date: Sat Mar 17 07:23:06 2007
New Revision: 519324
URL: http://svn.apache.org/viewvc?view=rev&rev=519324
Log:
o adding Ralph's documentation for the new depMan behavior
Modified:
maven/site/trunk/src/site/apt/guides/introduction/introduction-to-dependency-mechanism.apt
Modified:
maven/site/trunk/src/site/apt/guides/introduction/introduction-to-dependency-mechanism.apt
URL:
http://svn.apache.org/viewvc/maven/site/trunk/src/site/apt/guides/introduction/introduction-to-dependency-mechanism.apt?view=diff&rev=519324&r1=519323&r2=519324
==============================================================================
---
maven/site/trunk/src/site/apt/guides/introduction/introduction-to-dependency-mechanism.apt
(original)
+++
maven/site/trunk/src/site/apt/guides/introduction/introduction-to-dependency-mechanism.apt
Sat Mar 17 07:23:06 2007
@@ -51,6 +51,13 @@
then D 1.0 will be used when building A because the path from A to D
through E is shorter.
You could explicitly add a dependency to D 2.0 in A to force the use
of D 2.0
+ * <Dependency management>
+ - this allows project authors to directly specify the versions of
artifiacts to be used when they are encountered
+ in transitive dependencies or in dependencies where no version has been
specified. In the example in
+ the preceding section a dependency was directly added to A even though it
is not directly used by A. Instead,
+ A can include D as a dependency in its dependencyManagement section and
directly control which version of
+ D is used when, or if, it is ever referenced.
+
* <Dependency scope>
- this allows you to only include dependencies appropriate for the current
stage
of the build. This is described in more detail below.
@@ -271,9 +278,111 @@
identity set to <<\{groupId, artifactId\}>>, since the default for the type
field
is <<<jar>>>, and the default classifier is null.
+ A second, and very important use of the dependency management section is to
control the versions
+ of artifacts used in transitive dependencies. As an example consider these
projects:
+
+ Project A:
+
++----+
+
+<project>
+ <modelVersion>4.0.0</modelVersion>
+ <groupId>maven</groupId>
+ <artifactId>A</artifactId>
+ <packaging>pom</packaging>
+ <name>A</name>
+ <version>1.0</version>
+ <dependencyManagement>
+ <dependencies>
+ <dependency>
+ <groupId>test</groupId>
+ <artifactId>a</artifactId>
+ <version>1.2</version>
+ </dependency>
+ <dependency>
+ <groupId>test</groupId>
+ <artifactId>b</artifactId>
+ <version>1.0</version>
+ <scope>compile</scope>
+ </dependency>
+ <dependency>
+ <groupId>test</groupId>
+ <artifactId>c</artifactId>
+ <version>1.0</version>
+ <scope>compile</scope>
+ </dependency>
+ <dependency>
+ <groupId>test</groupId>
+ <artifactId>d</artifactId>
+ <version>1.2</version>
+ </dependency>
+ </dependencies>
+ </dependencyManagement>
+</project>
+
++----+
+
+ Project B:
+
++----+
+
+<project>
+ <parent>
+ <artifactId>A</artifactId>
+ <groupId>maven</groupId>
+ <version>1.0</version>
+ </parent>
+ <modelVersion>4.0.0</modelVersion>
+ <groupId>maven</groupId>
+ <artifactId>B</artifactId>
+ <packaging>pom</packaging>
+ <name>B</name>
+ <version>1.0</version>
+ <dependencyManagement>
+ <dependencies>
+ <dependency>
+ <groupId>test</groupId>
+ <artifactId>d</artifactId>
+ <version>1.0</version>
+ </dependency>
+ </dependencies>
+ </dependencyManagement>
+ <dependencies>
+ <dependency>
+ <groupId>maven-test</groupId>
+ <artifactId>a</artifactId>
+ <version>1.0</version>
+ <scope>runtime</scope>
+ </dependency>
+ <dependency>
+ <groupId>maven-test</groupId>
+ <artifactId>c</artifactId>
+ <scope>runtime</scope>
+ </dependency>
+ </dependencies>
+</project>
+
++----+
+
+ When maven is run on project B version 1.0 of artifacts a, b, c, and d will
be used regardless of
+ the version specified in their pom.
+
+ * a and c both are declared as dependencies of the project so version 1.0 is
used due to
+ dependency mediation. Both will also have runtime scope since it is directly
specified.
+
+ * b is defined in B's parent's dependency managemnet section and since
dependency management
+ takes precedence over dependency mediation for transitive dependencies,
version 1.0 will be
+ selected should it be referenced in a or c's pom. b will also have compile
scope.
+
+ * Finally, since d is specified in B's dependency management section, should
d be a dependency
+ (or transitive dependency) of a or c, version 1.0 will be chosen - again
because dependency
+ management takes precedence over dependency mediation and also because the
current pom's
+ declaration takes precedence over its parent's declaration.
+
+ []
The reference information about the dependency management tags is available
from the
- {{{maven-model/maven.html#class_DependencyManagement}project descriptor
reference}}. -----
+
{{{../../ref/current/maven-model/maven.html#class_DependencyManagement}project
descriptor reference}}.
* System Dependencies
