Removes the jpa facet when it's not used.

README.md

@@ -33,6 +33,10 @@ Please provide a unit test(s) for any patch and if one doesn't exist it may not
 * 2/2 spacing
 * 120 characters for lines and comments
 
+##Flags
+
+* Jpa facet will turn on if the artifact `<groupId>javax.jdo</groupId> <artifactId>jdo-api</artifactId>` exists.
+
 #GPE V1
 
 ##Links

plugins/com.google.appengine.eclipse.wtp.maven/.settings/org.eclipse.jdt.core.prefs

@@ -398,7 +398,7 @@ org.eclipse.jdt.core.formatter.keep_else_statement_on_same_line=false
 org.eclipse.jdt.core.formatter.keep_empty_array_initializer_on_one_line=false
 org.eclipse.jdt.core.formatter.keep_imple_if_on_one_line=true
 org.eclipse.jdt.core.formatter.keep_then_statement_on_same_line=false
-org.eclipse.jdt.core.formatter.lineSplit=100
+org.eclipse.jdt.core.formatter.lineSplit=120
 org.eclipse.jdt.core.formatter.never_indent_block_comments_on_first_column=false
 org.eclipse.jdt.core.formatter.never_indent_line_comments_on_first_column=false
 org.eclipse.jdt.core.formatter.number_of_blank_lines_at_beginning_of_method_body=0

plugins/com.google.appengine.eclipse.wtp.maven/.settings/org.eclipse.jdt.ui.prefs

@@ -10,7 +10,7 @@ comment_new_line_for_parameter=false
 comment_separate_root_tags=true
 eclipse.preferences.version=1
 editor_save_participant_org.eclipse.jdt.ui.postsavelistener.cleanup=true
-formatter_profile=_GPE
+formatter_profile=_GWT-Plugin
 formatter_settings_version=12
 org.eclipse.jdt.ui.exception.name=e
 org.eclipse.jdt.ui.gettersetter.use.is=true

plugins/com.google.appengine.eclipse.wtp.maven/src/com/google/appengine/eclipse/wtp/maven/Constants.java

@@ -21,14 +21,17 @@ public class Constants {
   // Components of appengine-maven-plugin Maven coordinates:
   public static final String APPENGINE_GROUP_ID = "com.google.appengine";
   public static final String APPENGINE_MAVEN_PLUGIN_ARTIFACT_ID = "appengine-maven-plugin";
-  
+
   // Components of datanucleus-maven-plugin coordinates:
   public static final String DATANUCLEUS_GROUP_ID = "org.datanucleus";
   public static final String DATANUCLEUS_MAVEN_PLUGIN_ARTIFACT_ID = "datanucleus-maven-plugin";
-  
+
   // Facet IDs:
   public static final String GAE_WAR_FACET_ID = IGaeFacetConstants.GAE_FACET_ID;
   public static final String GAE_EAR_FACET_ID = IGaeFacetConstants.GAE_EAR_FACET_ID;
   public static final String JPA_FACET_ID = "jpt.jpa";
 
+  // JPA artifact <groupId>javax.jdo</groupId> <artifactId>jdo-api</artifactId>
+  public static final String JPA_ARTIFACT = "jdo-api";
+
 }

plugins/com.google.appengine.eclipse.wtp.maven/src/com/google/appengine/eclipse/wtp/maven/GaeProjectConfigurator.java

@@ -14,8 +14,6 @@
  *******************************************************************************/
 package com.google.appengine.eclipse.wtp.maven;
 
-import java.util.List;
-
 import org.apache.maven.model.Model;
 import org.apache.maven.model.Plugin;
 import org.apache.maven.plugin.MojoExecution;
@@ -30,10 +28,13 @@
 import org.eclipse.wst.common.project.facet.core.IFacetedProject;
 import org.eclipse.wst.common.project.facet.core.ProjectFacetsManager;
 
+import java.util.List;
+
 /**
  * A {@link WTPProjectConfigurator} that adds GAE and JPA facets to GAE projects.
  */
-@SuppressWarnings("restriction") // WTPProjectConfigurator
+@SuppressWarnings("restriction")
+// WTPProjectConfigurator
 public class GaeProjectConfigurator extends WTPProjectConfigurator {
 
   @Override
@@ -44,18 +45,19 @@ public void configure(ProjectConfigurationRequest request, IProgressMonitor moni
       IProject eclipseProject = request.getProject();
       IFacetedProject facetedProject = ProjectFacetsManager.create(eclipseProject);
       new GaeFacetManager().addGaeFacet(pom, facetedProject, monitor);
-      new JpaFacetManager().configureJpaFacet(facetedProject, monitor);
+
+      // Only turn on the facet if the jpa artifact exists
+      new JpaFacetManager().configureJpaFacet(facetedProject, monitor, isJpaProject(pom));
     }
   }
 
   @Override
-  public AbstractBuildParticipant getBuildParticipant(
-      IMavenProjectFacade projectFacade, MojoExecution execution,
-      IPluginExecutionMetadata executionMetadata) {
+  public AbstractBuildParticipant getBuildParticipant(IMavenProjectFacade projectFacade,
+      MojoExecution execution, IPluginExecutionMetadata executionMetadata) {
     AppEngineMavenPlugin.logInfo("GaeProjectConfigurator.getBuildParticipant invoked");
     return super.getBuildParticipant(projectFacade, execution, executionMetadata);
   }
-  
+
   private static boolean isGaeProject(Model pom) {
     List<Plugin> plugins = pom.getBuild().getPlugins();
     for (Plugin plugin : plugins) {
@@ -67,4 +69,17 @@ private static boolean isGaeProject(Model pom) {
     return false;
   }
 
+  /**
+   * If there is a JPA artifact, turn on JPA or turn it off
+   */
+  private boolean isJpaProject(Model pom) {
+    List<Plugin> plugins = pom.getBuild().getPlugins();
+    for (Plugin plugin : plugins) {
+      if (Constants.JPA_ARTIFACT.equals(plugin.getArtifactId())) {
+        return true;
+      }
+    }
+    return false;
+  }
+
 }

plugins/com.google.appengine.eclipse.wtp.maven/src/com/google/appengine/eclipse/wtp/maven/JpaFacetManager.java

@@ -31,52 +31,71 @@
  */
 public class JpaFacetManager {
 
-  private static final String APP_ENGINE_JPA_PLATFORM_ID =
-      "com.google.appengine.eclipse.wtp.jpa.GaePlatform";
-      // Defined in the org.eclipse.jpt.jpa.core.jpaPlatforms extension point in
-      // com.google.appengine.eclipse.wtp.jpa.e43/plugin.xml
+  private static final String APP_ENGINE_JPA_PLATFORM_ID = "com.google.appengine.eclipse.wtp.jpa.GaePlatform";
+
+  // Defined in the org.eclipse.jpt.jpa.core.jpaPlatforms extension point in
+  // com.google.appengine.eclipse.wtp.jpa.e43/plugin.xml
 
   /**
    * Configures the JPA facet of a specified faceted project to use the implementation of JPA
    * bundled with App Engine, by ensuring that the latest JPA project facet is installed, setting
-   * the JPA platform in project preferences to App Engine, and adding the builder for the
-   * App Engine Datanucleus enhancer to the project.
+   * the JPA platform in project preferences to App Engine, and adding the builder for the App
+   * Engine Datanucleus enhancer to the project.
    *
    * @param facetedProject the specified faceted project
    * @param monitor a progress monitor for the operation
+   * @param enableFacet
    * @throws CoreException if there is an error adding the builder
    */
-  public void configureJpaFacet(
-      IFacetedProject facetedProject, IProgressMonitor monitor) throws CoreException {
-    IProjectFacetVersion installedVersion =
-        ensureLatestJpaFacetVersionInstalled(facetedProject, monitor);
-    if (installedVersion != null) {
-      JpaFacetHelper.setJpaPlatformId(facetedProject.getProject(), APP_ENGINE_JPA_PLATFORM_ID);
-      BuilderUtilities.addBuilderToProject(
-          facetedProject.getProject(), AppEnginePlugin.PLUGIN_ID + ".enhancerbuilder");
+  public void configureJpaFacet(IFacetedProject facetedProject, IProgressMonitor monitor, boolean enableFacet)
+      throws CoreException {
+    if (enableFacet) {
+      IProjectFacetVersion installedVersion = ensureLatestJpaFacetVersionInstalled(facetedProject, monitor);
+      if (installedVersion != null) {
+        JpaFacetHelper.setJpaPlatformId(facetedProject.getProject(), APP_ENGINE_JPA_PLATFORM_ID);
+        BuilderUtilities.addBuilderToProject(facetedProject.getProject(), AppEnginePlugin.PLUGIN_ID
+            + ".enhancerbuilder");
+      }
+    } else {
+      removeProjectFacet(facetedProject, monitor);
+      BuilderUtilities.removeBuilderFromProject(facetedProject.getProject(), AppEnginePlugin.PLUGIN_ID
+          + ".enhancerbuilder");
     }
   }
 
+  /**
+   * Remove jpaFacet
+   *
+   * @param facetedProject
+   * @param monitor
+   * @throws CoreException
+   */
+  private void removeProjectFacet(IFacetedProject facetedProject, IProgressMonitor monitor) throws CoreException {
+    IProjectFacet jpaFacet = ProjectFacetsManager.getProjectFacet(Constants.JPA_FACET_ID);
+    IFacetedProjectWorkingCopy workingCopy = facetedProject.createWorkingCopy();
+    workingCopy.removeProjectFacet(jpaFacet);
+    workingCopy.commitChanges(monitor);
+  }
+
   /**
    * Ensure that the latest available JPA facet version is installed in a specified faceted project.
    * If no JPA facet is installed, the latest JPA facet version is installed. If an earlier JPA
    * facet version is installed, it is upgraded to the latest version.
    *
    * @param facetedProject the specified faceted project
    * @param monitor a progress monitor for the operation
-   * @return
-   *     the installed version, or {@code null} in the event (which is supposed to be impossible)
-   *     that no JPA facet version can be found
+   * @return the installed version, or {@code null} in the event (which is supposed to be
+   *         impossible) that no JPA facet version can be found
    */
-  private IProjectFacetVersion ensureLatestJpaFacetVersionInstalled(
-      IFacetedProject facetedProject, IProgressMonitor monitor) {
+  private IProjectFacetVersion ensureLatestJpaFacetVersionInstalled(IFacetedProject facetedProject,
+      IProgressMonitor monitor) {
     IProjectFacet jpaFacet = ProjectFacetsManager.getProjectFacet(Constants.JPA_FACET_ID);
     IFacetedProjectWorkingCopy workingCopy = facetedProject.createWorkingCopy();
+
     IProjectFacetVersion latestVersion = workingCopy.getHighestAvailableVersion(jpaFacet);
     if (latestVersion == null) {
       // This shouldn't happen.
-      AppEngineMavenPlugin.logError(
-          "Unable to find an available version of the JPA facet", null);
+      AppEngineMavenPlugin.logError("Unable to find an available version of the JPA facet", null);
       return null;
     }
     // Although it's not documented, the source code of the class implementing IFacetedProject