public void executeMojo()

in maven-core/src/main/java/org/apache/maven/plugin/DefaultPluginManager.java [411:573]
129 lines of code
20 McCabe index (conditional complexity)

    public void executeMojo( MavenProject project,
                             MojoExecution mojoExecution,
                             MavenSession session )
        throws ArtifactResolutionException, MojoExecutionException, MojoFailureException, ArtifactNotFoundException,
        InvalidDependencyVersionException, PluginManagerException, PluginConfigurationException
    {
        MojoDescriptor mojoDescriptor = mojoExecution.getMojoDescriptor();

        // NOTE: I'm putting these checks in here, since this is the central point of access for
        // anything that wants to execute a mojo.
        if ( mojoDescriptor.isProjectRequired() && !session.isUsingPOMsFromFilesystem() )
        {
            throw new MojoExecutionException( "Cannot execute mojo: " + mojoDescriptor.getGoal()
                + ". It requires a project with an existing pom.xml, but the build is not using one." );
        }

        if ( mojoDescriptor.isOnlineRequired() && session.getSettings().isOffline() )
        {
            // TODO: Should we error out, or simply warn and skip??
            throw new MojoExecutionException( "Mojo: " + mojoDescriptor.getGoal()
                + " requires online mode for execution. Maven is currently offline." );
        }

        if ( mojoDescriptor.isDependencyResolutionRequired() != null )
        {
            Collection projects;

            if ( mojoDescriptor.isAggregator() )
            {
                projects = session.getSortedProjects();
            }
            else
            {
                projects = Collections.singleton( project );
            }

            for ( Iterator i = projects.iterator(); i.hasNext(); )
            {
                MavenProject p = (MavenProject) i.next();

                resolveTransitiveDependencies( session, artifactResolver,
                                               mojoDescriptor.isDependencyResolutionRequired(), artifactFactory, p, mojoDescriptor.isAggregator() );
            }

            downloadDependencies( project, session, artifactResolver );
        }

        String goalName = mojoDescriptor.getFullGoalName();

        Mojo plugin;

        PluginDescriptor pluginDescriptor = mojoDescriptor.getPluginDescriptor();

        String goalId = mojoDescriptor.getGoal();
        String groupId = pluginDescriptor.getGroupId();
        String artifactId = pluginDescriptor.getArtifactId();
        String executionId = mojoExecution.getExecutionId();

        Xpp3Dom dom = project.getGoalConfiguration( groupId, artifactId, executionId, goalId );
        Xpp3Dom reportDom = project.getReportConfiguration( groupId, artifactId, executionId );
        dom = Xpp3Dom.mergeXpp3Dom( dom, reportDom );
        if ( mojoExecution.getConfiguration() != null )
        {
            dom = Xpp3Dom.mergeXpp3Dom( dom, mojoExecution.getConfiguration() );
        }

        plugin = getConfiguredMojo( session, dom, project, false, mojoExecution );

        // Event monitoring.
        String event = MavenEvents.MOJO_EXECUTION;
        EventDispatcher dispatcher = session.getEventDispatcher();

        String goalExecId = goalName;

        if ( mojoExecution.getExecutionId() != null )
        {
            goalExecId += " {execution: " + mojoExecution.getExecutionId() + "}";
        }

        dispatcher.dispatchStart( event, goalExecId );

        ClassLoader oldClassLoader = Thread.currentThread().getContextClassLoader();

        try
        {
            Thread.currentThread().setContextClassLoader(
                mojoDescriptor.getPluginDescriptor().getClassRealm().getClassLoader() );

            plugin.execute();

            dispatcher.dispatchEnd( event, goalExecId );
        }
        catch ( MojoExecutionException e )
        {
            session.getEventDispatcher().dispatchError( event, goalExecId, e );

            throw e;
        }
        catch ( MojoFailureException e )
        {
            session.getEventDispatcher().dispatchError( event, goalExecId, e );

            throw e;
        }
        catch ( LinkageError e )
        {
            if ( getLogger().isFatalErrorEnabled() )
            {
                getLogger().fatalError(
                                        plugin.getClass().getName() + "#execute() caused a linkage error ("
                                            + e.getClass().getName() + ") and may be out-of-date. Check the realms:" );

                ClassRealm pluginRealm = mojoDescriptor.getPluginDescriptor().getClassRealm();
                StringBuffer sb = new StringBuffer();
                sb.append( "Plugin realm = " + pluginRealm.getId() ).append( '\n' );
                for ( int i = 0; i < pluginRealm.getConstituents().length; i++ )
                {
                    sb.append( "urls[" + i + "] = " + pluginRealm.getConstituents()[i] );
                    if ( i != ( pluginRealm.getConstituents().length - 1 ) )
                    {
                        sb.append( '\n' );
                    }
                }
                getLogger().fatalError( sb.toString() );

                ClassRealm containerRealm = container.getContainerRealm();
                sb = new StringBuffer();
                sb.append( "Container realm = " + containerRealm.getId() ).append( '\n' );
                for ( int i = 0; i < containerRealm.getConstituents().length; i++ )
                {
                    sb.append( "urls[" + i + "] = " + containerRealm.getConstituents()[i] );
                    if ( i != ( containerRealm.getConstituents().length - 1 ) )
                    {
                        sb.append( '\n' );
                    }
                }
                getLogger().fatalError( sb.toString() );
            }

            session.getEventDispatcher().dispatchError( event, goalExecId, e );

            throw e;
        }
        finally
        {

            Thread.currentThread().setContextClassLoader( oldClassLoader );

            try
            {
                PlexusContainer pluginContainer = getPluginContainer( mojoDescriptor.getPluginDescriptor() );

                pluginContainer.release( plugin );
            }
            catch ( ComponentLifecycleException e )
            {
                if ( getLogger().isErrorEnabled() )
                {
                    getLogger().error( "Error releasing plugin - ignoring.", e );
                }
            }
        }
    }