[MNG-1903] Adding support for optional mojos within a lifecycle mapping.

git-svn-id: https://svn.apache.org/repos/asf/maven/components/trunk@367962 13f79535-47bb-0310-9956-ffa450edef68

maven-core/src/main/java/org/apache/maven/lifecycle/DefaultLifecycleExecutor.java

@@ -375,7 +375,7 @@ public class DefaultLifecycleExecutor
                     try
                     {
                         // definitely a CLI goal, can use prefix
-                        mojo = getMojoDescriptor( task, session, project, task, true );
+                        mojo = getMojoDescriptor( task, session, project, task, true, false );
                     }
                     catch ( PluginNotFoundException e )
                     {
@@ -481,7 +481,7 @@ public class DefaultLifecycleExecutor
         throws LifecycleExecutionException, BuildFailureException, PluginNotFoundException
     {
         // guaranteed to come from the CLI and not be part of a phase
-        MojoDescriptor mojoDescriptor = getMojoDescriptor( task, session, project, task, true );
+        MojoDescriptor mojoDescriptor = getMojoDescriptor( task, session, project, task, true, false );
         executeGoals( Collections.singletonList( new MojoExecution( mojoDescriptor ) ), forkEntryPoints, session,
                       project );
     }
@@ -959,6 +959,8 @@ public class DefaultLifecycleExecutor
     {
         Map mappings = findMappingsForLifecycle( session, project, lifecycle );
         
+        List optionalMojos = findOptionalMojosForLifecycle( session, project, lifecycle );
+        
         Map lifecycleMappings = new HashMap();
 
         for ( Iterator i = lifecycle.getPhases().iterator(); i.hasNext(); )
@@ -974,7 +976,12 @@ public class DefaultLifecycleExecutor
                     String goal = tok.nextToken().trim();
 
                     // Not from the CLI, don't use prefix
-                    MojoDescriptor mojoDescriptor = getMojoDescriptor( goal, session, project, selectedPhase, false );
+                    MojoDescriptor mojoDescriptor = getMojoDescriptor( goal, session, project, selectedPhase, false, optionalMojos.contains( goal ) );
+                    
+                    if ( mojoDescriptor == null )
+                    {
+                        continue;
+                    }
 
                     if ( mojoDescriptor.isDirectInvocationOnly() )
                     {
@@ -1045,6 +1052,41 @@ public class DefaultLifecycleExecutor
         return mappings;
     }
 
+    private List findOptionalMojosForLifecycle( MavenSession session, MavenProject project, Lifecycle lifecycle )
+        throws LifecycleExecutionException, PluginNotFoundException
+    {
+        String packaging = project.getPackaging();
+        List optionalMojos = null;
+
+        LifecycleMapping m = (LifecycleMapping) findExtension( project, LifecycleMapping.ROLE, packaging, session
+            .getSettings(), session.getLocalRepository() );
+        
+        if ( m != null )
+        {
+            optionalMojos = m.getOptionalMojos( lifecycle.getId() );
+        }
+
+        if ( optionalMojos == null )
+        {
+            try
+            {
+                m = (LifecycleMapping) session.lookup( LifecycleMapping.ROLE, packaging );
+                optionalMojos = m.getOptionalMojos( lifecycle.getId() );
+            }
+            catch ( ComponentLookupException e )
+            {
+                getLogger().debug( "Error looking up lifecycle mapping to retrieve optional mojos. Lifecycle ID: " + lifecycle.getId() + ". Error: " + e.getMessage(), e );
+            }
+        }
+        
+        if ( optionalMojos == null )
+        {
+            optionalMojos = Collections.EMPTY_LIST;
+        }
+
+        return optionalMojos;
+    }
+
     private Object findExtension( MavenProject project, String role, String roleHint, Settings settings,
                                   ArtifactRepository localRepository )
         throws LifecycleExecutionException, PluginNotFoundException
@@ -1334,7 +1376,7 @@ public class DefaultLifecycleExecutor
     }
 
     private MojoDescriptor getMojoDescriptor( String task, MavenSession session, MavenProject project,
-                                              String invokedVia, boolean canUsePrefix )
+                                              String invokedVia, boolean canUsePrefix, boolean isOptionalMojo )
         throws BuildFailureException, LifecycleExecutionException, PluginNotFoundException
     {
         String goal;
@@ -1342,6 +1384,8 @@ public class DefaultLifecycleExecutor
 
         PluginDescriptor pluginDescriptor = null;
 
+        try
+        {
             StringTokenizer tok = new StringTokenizer( task, ":" );
             int numTokens = tok.countTokens();
 
@@ -1349,9 +1393,9 @@ public class DefaultLifecycleExecutor
             {
                 if ( !canUsePrefix )
                 {
-                String msg = "Mapped-prefix lookup of mojos are only supported from direct invocation. " +
+                    String msg = "Mapped-prefix lookup of mojos are only supported from direct invocation. "
-                    "Please use specification of the form groupId:artifactId[:version]:goal instead. " +
+                        + "Please use specification of the form groupId:artifactId[:version]:goal instead. "
-                    "(Offending mojo: \'" + task + "\', invoked via: \'" + invokedVia + "\')";
+                        + "(Offending mojo: \'" + task + "\', invoked via: \'" + invokedVia + "\')";
                     throw new LifecycleExecutionException( msg );
                 }
 
@@ -1383,8 +1427,8 @@ public class DefaultLifecycleExecutor
                     {
                         Plugin buildPlugin = (Plugin) i.next();
 
-                    PluginDescriptor desc =
+                        PluginDescriptor desc = verifyPlugin( buildPlugin, project, session.getSettings(), session
-                        verifyPlugin( buildPlugin, project, session.getSettings(), session.getLocalRepository() );
+                            .getLocalRepository() );
                         if ( prefix.equals( desc.getGoalPrefix() ) )
                         {
                             plugin = buildPlugin;
@@ -1427,8 +1471,8 @@ public class DefaultLifecycleExecutor
             }
             else
             {
-            String message = "Invalid task '" + task + "': you must specify a valid lifecycle phase, or" +
+                String message = "Invalid task '" + task + "': you must specify a valid lifecycle phase, or"
-                " a goal in the format plugin:goal or pluginGroupId:pluginArtifactId:pluginVersion:goal";
+                    + " a goal in the format plugin:goal or pluginGroupId:pluginArtifactId:pluginVersion:goal";
                 throw new BuildFailureException( message );
             }
 
@@ -1445,12 +1489,34 @@ public class DefaultLifecycleExecutor
 
             MojoDescriptor mojoDescriptor = pluginDescriptor.getMojo( goal );
             if ( mojoDescriptor == null )
+            {
+                if ( isOptionalMojo )
+                {
+                    getLogger().info( "Skipping missing optional mojo: " + task );
+                }
+                else
                 {
                     throw new BuildFailureException( "Required goal not found: " + task );
                 }
+            }
 
             return mojoDescriptor;
         }
+        catch ( PluginNotFoundException e )
+        {
+            if ( isOptionalMojo )
+            {
+                getLogger().info( "Skipping missing optional mojo: " + task );
+                getLogger().debug( "Mojo: " + task + " could not be found. Reason: " + e.getMessage(), e );
+            }
+            else
+            {
+                throw e;
+            }
+        }
+        
+        return null;
+    }
 
     protected void line()
     {

maven-core/src/main/java/org/apache/maven/lifecycle/mapping/DefaultLifecycleMapping.java

@@ -37,6 +37,33 @@ public class DefaultLifecycleMapping
     /** @deprecated use lifecycles instead */
     private Map phases;
     
+    public List getOptionalMojos( String lifecycle )
+    {
+        if ( lifecycleMap == null )
+        {
+            lifecycleMap = new HashMap();
+
+            if ( lifecycles != null )
+            {
+                for ( Iterator i = lifecycles.iterator(); i.hasNext(); )
+                {
+                    Lifecycle l = (Lifecycle) i.next();
+                    lifecycleMap.put( l.getId(), l );
+                }
+            }
+        }
+        Lifecycle l = (Lifecycle) lifecycleMap.get( lifecycle );
+
+        if ( l != null )
+        {
+            return l.getOptionalMojos();
+        }
+        else
+        {
+            return null;
+        }
+    }
+
     public Map getPhases( String lifecycle )
     {
         if ( lifecycleMap == null )

maven-core/src/main/java/org/apache/maven/lifecycle/mapping/Lifecycle.java

@@ -16,6 +16,8 @@ package org.apache.maven.lifecycle.mapping;
  * limitations under the License.
  */
 
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Map;
 
 /**
@@ -33,6 +35,8 @@ public class Lifecycle
      */
     private Map phases;
     
+    private List optionalMojos = new ArrayList();
+
     /**
      * Method getId
      */
@@ -58,4 +62,19 @@ public class Lifecycle
     {
         this.id = id;
     } //-- void setId(String) 
+    
+    public void addOptionalMojo( String optionalMojo )
+    {
+        this.optionalMojos.add( optionalMojo );
+    }
+    
+    public void setOptionalMojos( List optionalMojos )
+    {
+        this.optionalMojos = optionalMojos;
+    }
+    
+    public List getOptionalMojos()
+    {
+        return this.optionalMojos;
+    }
 }

maven-core/src/main/java/org/apache/maven/lifecycle/mapping/LifecycleMapping.java

@@ -16,6 +16,7 @@ package org.apache.maven.lifecycle.mapping;
  * limitations under the License.
  */
 
+import java.util.List;
 import java.util.Map;
 
 /**
@@ -26,5 +27,7 @@ public interface LifecycleMapping
 {
     String ROLE = LifecycleMapping.class.getName();
 
+    List getOptionalMojos( String lifecycle );
+    
     Map getPhases( String lifecycle );
 }

maven-core/src/main/resources/META-INF/plexus/components.xml

@@ -306,6 +306,9 @@
               <install>org.apache.maven.plugins:maven-install-plugin:install</install>
               <deploy>org.apache.maven.plugins:maven-deploy-plugin:deploy</deploy>
             </phases>
+            <optional-mojos>
+              <optional-mojo>org.apache.maven.plugins:maven-site-plugin:attach-descriptor</optional-mojo>
+            </optional-mojos>
             <!-- END SNIPPET: pom-lifecycle -->
           </lifecycle>
         </lifecycles>