From e095874576ce8ee75817338aded5a47525020277 Mon Sep 17 00:00:00 2001 From: John Dennis Casey Date: Thu, 5 May 2005 01:33:42 +0000 Subject: [PATCH] Cleaned up plugin descriptor generation/reading to be more consistent, and to include some things that were being left out. Removed more deprecated behavior from annotations support and expression support. Wrote up the first pass on the mojo api and annotations spec. Fixed the mmld-mojo suppport to accommodate the new expression syntax and collisions with the default expression evaluator for mmld. Added an exception to plugin configuration in DefaultPluginManager to not look for a Field when the configurator == map-oriented. git-svn-id: https://svn.apache.org/repos/asf/maven/components/trunk@168233 13f79535-47bb-0310-9956-ffa450edef68 --- .../org/apache/maven/it0015/it0015.mmld | 2 +- .../maven/plugin/DefaultPluginManager.java | 4 +- .../plugin/descriptor/MojoDescriptor.java | 2 +- .../descriptor/PluginDescriptorBuilder.java | 25 +- .../generator/PluginDescriptorGenerator.java | 48 +- .../maven/tools/plugin/util/PluginUtils.java | 17 +- .../java/JavaMojoDescriptorExtractor.java | 45 +- .../tags/AbstractStringValuedBodyTag.java | 2 +- .../developing-plugins-with-marmalade.xml | 0 .../developers/mojo-api-specification.xml | 459 ++++++++++++++++++ maven-site/src/site/xdoc/index.xml | 2 +- maven-site/src/site/xdoc/navigation.xml | 2 +- 12 files changed, 556 insertions(+), 52 deletions(-) rename maven-site/src/site/xdoc/{ => developers}/developing-plugins-with-marmalade.xml (100%) create mode 100644 maven-site/src/site/xdoc/developers/mojo-api-specification.xml diff --git a/maven-core-it/it0015/src/main/scripts/org/apache/maven/it0015/it0015.mmld b/maven-core-it/it0015/src/main/scripts/org/apache/maven/it0015/it0015.mmld index 7bdf326a2e..d4a6b9bde8 100644 --- a/maven-core-it/it0015/src/main/scripts/org/apache/maven/it0015/it0015.mmld +++ b/maven-core-it/it0015/src/main/scripts/org/apache/maven/it0015/it0015.mmld @@ -5,8 +5,8 @@ outDir + java.lang.String ${project.build.directory} - target Output directory for files. diff --git a/maven-core/src/main/java/org/apache/maven/plugin/DefaultPluginManager.java b/maven-core/src/main/java/org/apache/maven/plugin/DefaultPluginManager.java index 93371babb5..69c43ec7a5 100644 --- a/maven-core/src/main/java/org/apache/maven/plugin/DefaultPluginManager.java +++ b/maven-core/src/main/java/org/apache/maven/plugin/DefaultPluginManager.java @@ -654,10 +654,10 @@ public class DefaultPluginManager Object value = expressionEvaluator.evaluate( expression ); - getLogger().debug( "Evaluated mojo parameter expression: \'" + expression + "\' to: " + value ); + getLogger().debug( "Evaluated mojo parameter expression: \'" + expression + "\' to: " + value + " for parameter: \'" + key + "\'" ); // TODO: remove. If there is a default value, required should have been removed by the descriptor generator - if ( value == null ) + if ( value == null && !"map-oriented".equals( goal.getComponentConfigurator() ) ) { Object defaultValue; try diff --git a/maven-plugin-descriptor/src/main/java/org/apache/maven/plugin/descriptor/MojoDescriptor.java b/maven-plugin-descriptor/src/main/java/org/apache/maven/plugin/descriptor/MojoDescriptor.java index e87cb8bc1d..9fbb95be60 100755 --- a/maven-plugin-descriptor/src/main/java/org/apache/maven/plugin/descriptor/MojoDescriptor.java +++ b/maven-plugin-descriptor/src/main/java/org/apache/maven/plugin/descriptor/MojoDescriptor.java @@ -154,7 +154,7 @@ public class MojoDescriptor this.requiresProject = requiresProject; } - public boolean isRequiresProject() + public boolean getRequiresProject() { return requiresProject; } diff --git a/maven-plugin-descriptor/src/main/java/org/apache/maven/plugin/descriptor/PluginDescriptorBuilder.java b/maven-plugin-descriptor/src/main/java/org/apache/maven/plugin/descriptor/PluginDescriptorBuilder.java index 02189811ee..80f66bd0df 100755 --- a/maven-plugin-descriptor/src/main/java/org/apache/maven/plugin/descriptor/PluginDescriptorBuilder.java +++ b/maven-plugin-descriptor/src/main/java/org/apache/maven/plugin/descriptor/PluginDescriptorBuilder.java @@ -100,6 +100,13 @@ public class PluginDescriptorBuilder mojo.setComponentConfigurator( configuratorConfig.getValue() ); } + PlexusConfiguration composerConfig = c.getChild( "composer" ); + + if ( composerConfig != null ) + { + mojo.setComponentComposer( composerConfig.getValue() ); + } + String phase = c.getChild( "phase" ).getValue(); if ( phase != null ) @@ -125,6 +132,20 @@ public class PluginDescriptorBuilder mojo.setRequiresDependencyResolution( dependencyResolution ); } + String requiresProject = c.getChild( "requiresProject" ).getValue(); + + if ( requiresProject != null ) + { + mojo.setRequiresProject( "true".equals( requiresProject ) ); + } + + String requiresOnline = c.getChild( "requiresOnline" ).getValue(); + + if ( requiresOnline != null ) + { + mojo.setRequiresOnline( "true".equals( requiresOnline ) ); + } + // ---------------------------------------------------------------------- // Parameters // ---------------------------------------------------------------------- @@ -163,12 +184,8 @@ public class PluginDescriptorBuilder parameter.setDescription( d.getChild( "description" ).getValue() ); - // TODO: remove parameter.setExpression( d.getChild( "expression" ).getValue() ); - // TODO: remove - parameter.setDefaultValue( d.getChild( "default" ).getValue() ); - parameter.setDeprecated( d.getChild( "deprecated" ).getValue() ); parameters.add( parameter ); diff --git a/maven-plugin-tools/maven-plugin-tools-api/src/main/java/org/apache/maven/tools/plugin/generator/PluginDescriptorGenerator.java b/maven-plugin-tools/maven-plugin-tools-api/src/main/java/org/apache/maven/tools/plugin/generator/PluginDescriptorGenerator.java index 38bd713b20..124be80826 100644 --- a/maven-plugin-tools/maven-plugin-tools-api/src/main/java/org/apache/maven/tools/plugin/generator/PluginDescriptorGenerator.java +++ b/maven-plugin-tools/maven-plugin-tools-api/src/main/java/org/apache/maven/tools/plugin/generator/PluginDescriptorGenerator.java @@ -71,9 +71,7 @@ public class PluginDescriptorGenerator element( w, "goalPrefix", goalPrefix ); - element( w, "isolatedRealm", "true" ); - - w.startElement( "mojos" ); + w.startElement( "mojos" ); for ( Iterator it = mavenMojoDescriptors.iterator(); it.hasNext(); ) { @@ -122,6 +120,18 @@ public class PluginDescriptorGenerator // // ---------------------------------------------------------------------- + element( w, "requiresProject", "" + mojoDescriptor.getRequiresProject() ); + + // ---------------------------------------------------------------------- + // + // ---------------------------------------------------------------------- + + element( w, "requiresOnline", "" + mojoDescriptor.requiresOnline() ); + + // ---------------------------------------------------------------------- + // + // ---------------------------------------------------------------------- + if ( mojoDescriptor.getPhase() != null ) { element( w, "phase", mojoDescriptor.getPhase() ); @@ -173,6 +183,19 @@ public class PluginDescriptorGenerator // // ---------------------------------------------------------------------- + if ( mojoDescriptor.getComponentComposer() != null ) + { + w.startElement( "composer" ); + + w.writeText( mojoDescriptor.getComponentComposer() ); + + w.endElement(); + } + + // ---------------------------------------------------------------------- + // + // ---------------------------------------------------------------------- + w.startElement( "instantiationStrategy" ); w.writeText( mojoDescriptor.getInstantiationStrategy() ); @@ -205,8 +228,7 @@ public class PluginDescriptorGenerator String expression = parameter.getExpression(); - if ( StringUtils.isNotEmpty( expression ) && - ( expression.startsWith( "${component." ) || expression.startsWith( "#component." ) ) ) + if ( StringUtils.isNotEmpty( expression ) && expression.startsWith( "${component." ) ) { // treat it as a component...a requirement, in other words. @@ -241,11 +263,6 @@ public class PluginDescriptorGenerator element( w, "description", parameter.getDescription() ); - if ( StringUtils.isEmpty( expression ) ) - { - expression = parameter.getDefaultValue(); - } - if ( expression != null && expression.length() > 0 ) { configuration.put( parameter, expression ); @@ -300,17 +317,10 @@ public class PluginDescriptorGenerator w.startElement( "requirement" ); - String role; // remove "component." plus expression delimiters String expression = requirement.getExpression(); - if ( expression.startsWith( "${" ) ) - { - role = expression.substring( "${component.".length(), expression.length() - 1 ); - } - else - { - role = expression.substring( "#component.".length() ); - } + String role = expression.substring( "${component.".length(), expression.length() - 1 ); + element( w, "role", role ); element( w, "field-name", requirement.getName() ); diff --git a/maven-plugin-tools/maven-plugin-tools-api/src/main/java/org/apache/maven/tools/plugin/util/PluginUtils.java b/maven-plugin-tools/maven-plugin-tools-api/src/main/java/org/apache/maven/tools/plugin/util/PluginUtils.java index 48ec622fd9..e03761c9b8 100644 --- a/maven-plugin-tools/maven-plugin-tools-api/src/main/java/org/apache/maven/tools/plugin/util/PluginUtils.java +++ b/maven-plugin-tools/maven-plugin-tools-api/src/main/java/org/apache/maven/tools/plugin/util/PluginUtils.java @@ -16,6 +16,7 @@ package org.apache.maven.tools.plugin.util; * limitations under the License. */ +import org.apache.maven.artifact.Artifact; import org.apache.maven.model.Dependency; import org.apache.maven.project.MavenProject; import org.codehaus.plexus.util.DirectoryScanner; @@ -67,17 +68,21 @@ public final class PluginUtils for ( Iterator it = project.getDependencies().iterator(); it.hasNext(); ) { Dependency dep = (Dependency) it.next(); - w.startElement( "dependency" ); + + if ( !Artifact.SCOPE_TEST.equals( dep.getScope() ) ) + { + w.startElement( "dependency" ); - PluginUtils.element( w, "groupId", dep.getGroupId() ); + PluginUtils.element( w, "groupId", dep.getGroupId() ); - PluginUtils.element( w, "artifactId", dep.getArtifactId() ); + PluginUtils.element( w, "artifactId", dep.getArtifactId() ); - PluginUtils.element( w, "type", dep.getType() ); + PluginUtils.element( w, "type", dep.getType() ); - PluginUtils.element( w, "version", dep.getVersion() ); + PluginUtils.element( w, "version", dep.getVersion() ); - w.endElement(); + w.endElement(); + } } w.endElement(); diff --git a/maven-plugin-tools/maven-plugin-tools-java/src/main/java/org/apache/maven/tools/plugin/extractor/java/JavaMojoDescriptorExtractor.java b/maven-plugin-tools/maven-plugin-tools-java/src/main/java/org/apache/maven/tools/plugin/extractor/java/JavaMojoDescriptorExtractor.java index f5b954743a..9a88d17198 100644 --- a/maven-plugin-tools/maven-plugin-tools-java/src/main/java/org/apache/maven/tools/plugin/extractor/java/JavaMojoDescriptorExtractor.java +++ b/maven-plugin-tools/maven-plugin-tools-java/src/main/java/org/apache/maven/tools/plugin/extractor/java/JavaMojoDescriptorExtractor.java @@ -50,13 +50,7 @@ public class JavaMojoDescriptorExtractor extends AbstractLogEnabled implements MojoDescriptorExtractor { - public static final String MAVEN_PLUGIN_ID = "maven.plugin.id"; - - public static final String MAVEN_PLUGIN_DESCRIPTION = "maven.plugin.description"; - - public static final String MAVEN_PLUGIN_INSTANTIATION = "maven.plugin.instantiation"; - - public static final String MAVEN_PLUGIN_MODE = "maven.plugin.mode"; + public static final String MAVEN_PLUGIN_INSTANTIATION = "instantiationStrategy"; public static final String PARAMETER = "parameter"; @@ -78,6 +72,10 @@ public class JavaMojoDescriptorExtractor public static final String GOAL_REQUIRES_DEPENDENCY_RESOLUTION = "requiresDependencyResolution"; + public static final String GOAL_REQUIRES_PROJECT = "requiresProject"; + + public static final String GOAL_REQUIRES_ONLINE = "requiresOnline"; + public static final String GOAL_MULTI_EXECUTION_STRATEGY = "attainAlways"; protected void validateParameter( Parameter parameter, int i ) @@ -123,16 +121,9 @@ public class JavaMojoDescriptorExtractor mojoDescriptor.setImplementation( javaClass.getFullyQualifiedName() ); - DocletTag tag; + mojoDescriptor.setDescription( javaClass.getComment() ); - tag = findInClassHierarchy( javaClass, MAVEN_PLUGIN_DESCRIPTION ); - - if ( tag != null ) - { - mojoDescriptor.setDescription( tag.getValue() ); - } - - tag = findInClassHierarchy( javaClass, MAVEN_PLUGIN_INSTANTIATION ); + DocletTag tag = findInClassHierarchy( javaClass, MAVEN_PLUGIN_INSTANTIATION ); if ( tag != null ) { @@ -199,6 +190,28 @@ public class JavaMojoDescriptorExtractor mojoDescriptor.setRequiresDependencyResolution( value ); } + // ---------------------------------------------------------------------- + // Project flag + // ---------------------------------------------------------------------- + + DocletTag requiresProject = findInClassHierarchy( javaClass, GOAL_REQUIRES_PROJECT ); + + if ( requiresProject != null ) + { + mojoDescriptor.setRequiresProject( true ); + } + + // ---------------------------------------------------------------------- + // Online flag + // ---------------------------------------------------------------------- + + DocletTag requiresOnline = findInClassHierarchy( javaClass, GOAL_REQUIRES_ONLINE ); + + if ( requiresOnline != null ) + { + mojoDescriptor.setRequiresOnline( true ); + } + extractParameters( mojoDescriptor, javaClass ); return mojoDescriptor; diff --git a/maven-script/maven-script-marmalade/src/main/java/org/apache/maven/script/marmalade/tags/AbstractStringValuedBodyTag.java b/maven-script/maven-script-marmalade/src/main/java/org/apache/maven/script/marmalade/tags/AbstractStringValuedBodyTag.java index 713df27bf5..d203f412da 100644 --- a/maven-script/maven-script-marmalade/src/main/java/org/apache/maven/script/marmalade/tags/AbstractStringValuedBodyTag.java +++ b/maven-script/maven-script-marmalade/src/main/java/org/apache/maven/script/marmalade/tags/AbstractStringValuedBodyTag.java @@ -34,7 +34,7 @@ public abstract class AbstractStringValuedBodyTag protected void doExecute( MarmaladeExecutionContext context ) throws MarmaladeExecutionException { - String bodyValue = (String) getBody( context, String.class ); + String bodyValue = getRawBody( context ); setValue( bodyValue ); } diff --git a/maven-site/src/site/xdoc/developing-plugins-with-marmalade.xml b/maven-site/src/site/xdoc/developers/developing-plugins-with-marmalade.xml similarity index 100% rename from maven-site/src/site/xdoc/developing-plugins-with-marmalade.xml rename to maven-site/src/site/xdoc/developers/developing-plugins-with-marmalade.xml diff --git a/maven-site/src/site/xdoc/developers/mojo-api-specification.xml b/maven-site/src/site/xdoc/developers/mojo-api-specification.xml new file mode 100644 index 0000000000..ed9b75b709 --- /dev/null +++ b/maven-site/src/site/xdoc/developers/mojo-api-specification.xml @@ -0,0 +1,459 @@ + + + + + + Maven 2.0 - Mojo API Specification + John Casey + + +
+

Starting with Maven 2.0, plugins can be written in Java or any of a + number of scripting languages (currently just marmalade - we are + working to implement others). Additionally, Maven tries to stay out of + the way of the programmer with its new Mojo API. This opens up the + opportunity for many Mojos to be reused outside of Maven, or bridged + into Maven from external systems like Ant.

+

NOTE: For now, we will limit the discussion to Java-based mojos, since + each scripting language will present these same basic requirements with + various forms of implementation.

+

Although the requirements on Mojos are minimal by design, there are + still a very few requirements that Mojo developers must keep in mind. Basically, these Mojo requirements are embodied by the + org.apache.maven.plugin.Mojo interface, which the Mojo + must implement (or else extend its abstract base class counterpart + org.apache.maven.plugin.AbstractMojo). This interface + guarantees the correct execution contract for the mojo: no parameters, + void return type, and a throws clause that allows only + org.apache.maven.plugin.MojoExecutionException and its + derivatives. It also guarantees that the Mojo will have access to the + standard Maven user-feedback mechanism, + org.apache.maven.monitor.logging.Log, so the Mojo can + communicate important events to the console or other log sink.

+

As mentioned before, each Plugin - or packaged set of Mojos - must + provide a descriptor called plugin.xml under the path + META-INF/maven inside the Plugin jar file. Fortunately, + Maven also provides a set of javadoc annotations and tools to generate + this descriptor, so developers don't have to worry about directly + authoring or maintaining a separate XML metadata file.

+

To serve as a quick reference for the developer, the rest of this page + will document these features (the API, along with the annotations) + which are considered the best practice for developing Mojos.

+
+
+ +

This interface forms the contract required for Mojos to interact + with the Maven infrastructure. It features an execute() + method, which trigger's the Mojo's build-process behavior, and can + throw a MojoExecutionException if an error condition + occurs. See below for a discussion on proper use of this + Exception class. Also included is the + setLog(..) method, which simply allows Maven to inject a + logging mechanism which will allow the Mojo to communicate to the + outside world through standard Maven channels.

+

+

    + + Method Summary: + +
  • + + void setLog( org.apache.maven.monitor.logging.Log ) + +

    Inject a standard Maven logging mechanism to allow this Mojo + to communicate events and feedback to the user.

    +
    • +
  • + + void execute() throws org.apache.maven.plugin.MojoExecutionException + +

    Perform whatever build-process behavior this Mojo implements. + This is the main trigger for the Mojo inside the Maven system, + and allows the Mojo to communicate fatal errors by throwing an + instance of MojoExecutionException.

    +

    The MojoExecutionException (and all error + conditions inside the Mojo) should be handled very carefully. + The simple wrapping of lower-level exceptions without providing + any indication of a user-friendly probable cause is strictly + discouraged. In fact, a much better course of action is to + provide error handling code (try/catch stanzas) for each + coherent step within the Mojo's execution. Developers are then + in a much better position to diagnose the cause of any error, + and provide user-friendly feedback in the message of the + MojoExecutionException.

    +
    • +
+

+ + +

Currently, this abstract base class simply takes care of managing + the Maven log for concrete derivations. In keeping with this, it + provides a protected method, getLog():Log, + to furnish Log access to these concrete implementations.

+

+

    + + Method Summary: + +
  • + + public void setLog( org.apache.maven.monitor.logging.Log ) + +

    + [IMPLEMENTED] +

    +

    Inject a standard Maven logging mechanism to allow this Mojo + to communicate events and feedback to the user.

    +
    • +
  • + protected Log getLog() +

    + [IMPLEMENTED] +

    +

    Furnish access to the standard Maven logging mechanism which + is managed in this base class.

    +
    • +
  • + + void execute() throws org.apache.maven.plugin.MojoExecutionException + +

    + [ABSTRACT] +

    +

    Perform whatever build-process behavior this Mojo implements. + See the documentation for Mojo above for more + information.

    +
    • +
+

+ + +

This interface supplies the API for providing feedback to the user + from the Mojo, using standard Maven channels. There should be no big + surprises here, although you may notice that the methods accept + java.lang.CharSequence rather than + java.lang.String. This is provided mainly as a + convenience, to enable developers to pass things like + StringBuffer directly into the logger, rather than + formatting first by calling toString().

+

+

    + + Method Summary: + +
  • + void debug( java.lang.CharSequence ) +

    Send a message to the user in the debug error level.

    +
    • +
  • + + void debug( java.lang.CharSequence, java.lang.Throwable ) + +

    Send a message (and accompanying exception) to the user in the + debug error level. The error's stacktrace will be output + when this error level is enabled.

    +
    • +
  • + void debug( java.lang.Throwable ) +

    Send an exception to the user in the debug error level. + The stack trace for this exception will be output when this + error level is enabled.

    +
    • +
  • + void info( java.lang.CharSequence ) +

    Send a message to the user in the info error level.

    +
    • +
  • + + void info( java.lang.CharSequence, java.lang.Throwable ) + +

    Send a message (and accompanying exception) to the user in the + info error level. The error's stacktrace will be output + when this error level is enabled.

    +
    • +
  • + void info( java.lang.CharSequence ) +

    Send an exception to the user in the info error level. + The stack trace for this exception will be output when this + error level is enabled.

    +
    • +
  • + void warn( java.lang.CharSequence ) +

    Send a message to the user in the warn error level.

    +
    • +
  • + + void warn( java.lang.CharSequence, java.lang.Throwable ) + +

    Send a message (and accompanying exception) to the user in the + warn error level. The error's stacktrace will be output + when this error level is enabled.

    +
    • +
  • + void warn( java.lang.CharSequence ) +

    Send an exception to the user in the warn error level. + The stack trace for this exception will be output when this + error level is enabled.

    +
    • +
  • + void error( java.lang.CharSequence ) +

    Send a message to the user in the error error level.

    +
    • +
  • + + void error( java.lang.CharSequence, java.lang.Throwable ) + +

    Send a message (and accompanying exception) to the user in the + error error level. The error's stacktrace will be output + when this error level is enabled.

    +
    • +
  • + void error( java.lang.CharSequence ) +

    Send an exception to the user in the error error level. + The stack trace for this exception will be output when this + error level is enabled.

    +
    • +
+

+ +
+
+

In addition to the normal Java requirements in terms of interfaces + and/or abstract base classes which need to be implemented, a plugin + descriptor must accompany these classes inside the plugin jar. This + descriptor file is used to provide metadata about the parameters and + other component requirements for a set of Mojos so that Maven can + initialize the Mojo and validate it's configuration before executing + it. As such, the plugin descriptor has a certain set of information + that is required for each Mojo specification to be valid, as well as + requirements for the overall plugin descriptor itself.

+

NOTE: In the following discussion, bolded items are the descriptor's + element name along with a javadoc annotation (if applicable) supporting + that piece of the plugin descriptor. A couple of examples are: + someElement + (@annotation parameterName="parameterValue") or + someOtherElement (@annotation <rawAnnotationValue>).

+

The plugin descriptor must be provided in a jar resource with the + path: META-INF/maven/plugin.xml, and it must contain the + following:

+

+

    +
  • mojos - Descriptors for each Mojo provided by + the plugin, each inside a mojo sub-element. Mojo descriptors + are covered in detail below.
    • +
  • dependencies - A set of dependencies which the + plugin requires in order to function. Each dependency is provided + inside a dependency sub-element. Dependency specifications + are covered below. Using the plugin toolset, these dependencies + can be extracted from the POM's dependencies.
    • +
+

+

Each Mojo specified inside a plugin descriptor must provide the + following:

+

+

    +
  • goal. (@goal <goalName>) - The name for + the Mojo that users will reference from the command line to execute + the Mojo directly, or inside a POM in order to provide + Mojo-specific configuration.
    • +
  • implementation (detected) - The + Mojo's fully-qualified class name.
    • +
  • language (detected) - The implementation + language for this Mojo (marmalade, java, etc.). Optional, + default is java.
    • +
  • configurator (detected) - The configurator type + used to inject parameters into the Mojo. Optional; will only be + used in very special cases, with a highly controlled vocabulary of + possible values. (Elements like this are why it's a good idea to + use the descriptor tools.)
    • +
  • phase + (@phase <phaseName>) - Specifies to which + phase in the standard build lifecycle this Mojo binds. Optional; + only required if this Mojo participates in the standard build + process.
    • +
  • executePhase + (@executePhase <phaseName>) - Specifies + the last phase in the standard build lifecycle to execute before + executing this Mojo, when the Mojo's goal is invoked directly. + Optional.
    • +
  • instantiationStrategy + (@instantiationStrategy <strategyName>) - Specifies + the method Maven should use in instantiating this Mojo before it is + executed, which has implications for the Mojo's state and instance + reuse. Optional. Currently, only "per-lookup" is suppported. + (Brett: Can we deprecate this before alpha-2 + release?)
    • +
  • requiresDependencyResolution + (@requiresDependencyResolution <requiredScope>) - Flags + this Mojo as requiring the specified scope of dependencies to be + resolved before it can execute. Optional; Currently supports + "compile", "runtime", and "test" scopes.
    • +
  • description (detected) - The description of the + Mojo's functionality. Using the toolset, this will be the + class-level javadoc description provided.
    • +
  • parameters - Specifications for the parameters + which this Mojo uses. Each parameter is specified in a + parameter sub-element. Parameters are discusses in + detail below.
    • +
+

+

Each Mojo specifies the parameters that it expects to be able to work + with. These parameters are the Mojo's link to the outside world, and + will be satisfied through a combination of POM/project values, plugin + configurations (from the POM and configuration defaults), and System + properties.

+

NOTE[1]: For this discussion on Mojo parameters, a single + annotation may span multiple elements in the descriptor's specification + for that parameter. Duplicate annotation declarations in this section + will be used to detail each parameter of an annotation separately.

+

NOTE[2]: In many cases, simply annotating a Mojo field with + @parameter will be enough to allow injection of a value for that + parameter using POM configuration elements. The discussion below + shows advanced usage for this annotation, along with others.

+

Each parameter for a Mojo must be specified in the + plugin descriptor as follows:

+

+

    +
  • name (detected) - The name of the parameter, to + be used in configuring this parameter from the Mojo's declared + defaults (discussed below) or from the POM. Using the toolset, + this is detected as the java field name. It cannot be + specified in an annotation.
    • +
  • alias (@parameter alias="myAlias") - Specifies + an alias which can be used to configure this parameter from the + POM. This is primarily useful to improve user-friendliness, where + Mojo field names are not intuitive to the user. + Optional.
    • +
  • type (detected) - The type of this parameter. + This is used to validate the result of any expressions used to + calculate the value which should be injected into the Mojo for this + parameter. Using the toolset, this is detected as the class of + this parameter's java field. It cannot be specified in an + annotation.
    • +
  • required (@required) - Whether this parameter is + required for the Mojo to function. This is used to validate the + configuration for a Mojo before it is injected, and before the Mojo + is executed from some half-state. Optional. Specification of + this annotation flags the parameter as required; there is + no true/false value.
    • +
  • editable (@readonly) - Specifies that this + parameter cannot be configured directly by the user (as in the case + of POM-specified configuration). This is useful when you want to + force the user to use common POM elements rather than plugin + configurations, as in the case where you want to use the artifact's + final name as a parameter. In this case, you want the user to + modify <build><finalName/></build> rather than + specifying a value for finalName directly in the plugin + configuration section. It is also useful to ensure that - for + example - a List-typed parameter which expects items of type + Artifact doesn't get a List full of Strings. Optional. + Specification of this annotation flags the parameter as + non-editable; there is no true/false value.
    • +
  • description (detected) - The description for + what this parameter is used for inside the Mojo. Using the + toolset, this is detected as the javadoc description for + the field. It cannot be specified as an annotation.
    • +
  • expression + (@parameter expression="${someExpression}") - Specifies + the expression used to calculate the value to be injected into this + parameter of the Mojo at buildtime. This is commonly used to refer + to specific elements in the POM, such as + ${project.build.resources}, which refers to the List of resources + meant to accompany the classes in the resulting jar file. + Optional. If not specified, an expression of ${<name>} is + assumed, which can only be satisfied from POM configuration or + System properties. The use of '${' and '}' is required to + delimit actual expressions which may be evaluated.
    • +
  • deprecated (@deprecated) - Marks a parameter as + deprecated. The rules on deprecation are the same as normal java + with language elements. This will trigger a warning when a user + tries to configure a parameter marked as deprecated. + Optional.
    • +
+

+

The final component of a plugin descriptor is the dependencies. This + enables the plugin to function independently of it's POM (or at least + to declare the libraries it needs to run). Dependencies are taken from + the runtime scope of the plugin's calculated dependencies (from + the POM). Dependencies are specified in exactly the same manner as in + the POM, except for the <scope> element (all dependencies in the + plugin descriptor are assumed to be runtime, because this is a + runtime profile for the plugin).

+
+
+

By now, we've mentioned the plugin tools several times without telling + you what they are or how to use them. instead of writing (and + maintaining) this metadata file by hand, Maven 2.0 ships with some + tools to aid developers in this task. In fact, the only thing a plugin + developer needs to do is declare his project to be a plugin from within + the POM. Once this is done, Maven will call the appropriate descriptor + generators, etc. to produce an artifact that is ready for use within + Maven builds. The section below describes the changes to the POM + which are necessary to create plugin artifacts.

+
+
+

From the POM, Maven plugin projects look quite similar to any other + project. For pure java plugins, the differences are even smaller than + for script-based plugins. The following details the POM elements + which are necessary to build a Maven plugin artifact.

+

+

    +
  • packaging Element. The POM must declare a packaging + element which describes this project as a Maven plugin project. The + element is specified as: + <packaging>maven-plugin</packaging>
    • +
  • scriptSourceDirectory Element. In the case of script-based + Mojos (which are not covered in detail within this document), the + POM must include an additional element to distinguish script + sources from (optional) java supporting classes. This element is + the scriptSourceDirectory, inside the build section. It is + specified as: + <scriptSourceDirectory>src/main/scripts</scriptSourceDirectory>. + This directory is included in the list of resources which accompany + any compiled code in the resulting artifact. It is specified + separately from the resources in the build section to denote its + special status as an alternate source directory for scripts.
    • +
+

+

After making the changes above, the developer can simply call m2 + install to install the plugin to the local repository. (Any of + the other standard lifecycle targets like package, deploy, etc. are + also available in like fashion.)

+
+
+
+ + \ No newline at end of file diff --git a/maven-site/src/site/xdoc/index.xml b/maven-site/src/site/xdoc/index.xml index 3ef0984678..69470300d7 100644 --- a/maven-site/src/site/xdoc/index.xml +++ b/maven-site/src/site/xdoc/index.xml @@ -141,7 +141,7 @@ -->
  • - Developing Plugins with Marmalade + Developing Plugins with Marmalade
    • diff --git a/maven-site/src/site/xdoc/navigation.xml b/maven-site/src/site/xdoc/navigation.xml index 4c35885aab..ba63073135 100644 --- a/maven-site/src/site/xdoc/navigation.xml +++ b/maven-site/src/site/xdoc/navigation.xml @@ -17,7 +17,7 @@ - +