Enable m2e-apt by default

Also a small bugfix related to enabling spring-boot validation builder
on new projects.

Both of these contribute to make a smoother experience working with
JDT APT.

See: #822

Author: kdvolder

eclipse-extensions/org.springframework.ide.eclipse.boot.validation/src/org/springframework/ide/eclipse/boot/validation/BootValidationEnabler.java

@@ -109,7 +109,7 @@ private boolean hasBuilder(IProject p, String builderId) throws CoreException {
 	@Override
 	public void earlyStartup() {
 		//Don't do this stuff actually during startup. Its not critical and it can wait.
-		new ValidationEnablerStartupJob().schedule(Duration.ofMinutes(1).toMillis());
+		new ValidationEnablerStartupJob().schedule(Duration.ofSeconds(10).toMillis());
 	}
 
 }

eclipse-extensions/org.springframework.ide.eclipse.boot/plugin.xml

@@ -272,5 +272,7 @@
       point="org.springframework.ide.eclipse.boot.project">
       <project nature="org.eclipse.m2e.core.maven2Nature" projectClass="org.springframework.ide.eclipse.boot.core.internal.MavenSpringBootProject"></project>
 </extension>
-
+  <extension point="org.eclipse.ui.startup">
+     <startup class="org.springframework.ide.eclipse.boot.ui.preferences.MavenAptPreferenceInitializer"/>
+   </extension>
 </plugin>

eclipse-extensions/org.springframework.ide.eclipse.boot/src/org/springframework/ide/eclipse/boot/core/internal/MavenSpringBootProject.java

@@ -36,7 +36,6 @@
 import java.io.File;
 import java.lang.reflect.Constructor;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
@@ -337,7 +336,11 @@ public void updateProjectConfiguration() {
 			protected IStatus run(IProgressMonitor arg0) {
 				Job job = createUpdateMavenProjectJob(getProject());
 				if (job != null) {
-					job.schedule();
+					job.schedule(2000); //Without 2000ms delay, we tend to get deadlocks.
+					// TODO:              ^^^^ debug this and find a better solution (suspect this actually bug in m2e,
+					//                        but it rarely happens when a user invokes the operation from the UI.
+					//                        It happens here presumably because some updates happen in quick succession
+					//                        and this causes some sort of a race condition causing a deadlock situation.
 					return Status.OK_STATUS;
 				}
 				else {

eclipse-extensions/org.springframework.ide.eclipse.boot/src/org/springframework/ide/eclipse/boot/ui/preferences/MavenAptPreferenceInitializer.java

@@ -0,0 +1,34 @@
+package org.springframework.ide.eclipse.boot.ui.preferences;
+
+import org.eclipse.core.runtime.preferences.AbstractPreferenceInitializer;
+import org.eclipse.core.runtime.preferences.DefaultScope;
+import org.eclipse.core.runtime.preferences.IEclipsePreferences;
+import org.eclipse.core.runtime.preferences.InstanceScope;
+import org.eclipse.ui.IStartup;
+import org.osgi.service.prefs.BackingStoreException;
+import org.springframework.ide.eclipse.boot.core.BootActivator;
+import org.springsource.ide.eclipse.commons.livexp.util.Log;
+
+public class MavenAptPreferenceInitializer implements IStartup {
+
+	private static final String M2E_APT_PLUGIN_ID = "org.eclipse.m2e.apt";
+	private static final String PREF_MODE= M2E_APT_PLUGIN_ID+".mode";
+
+	private static final String PREF_STS_CUSTONISATIONS_APPLIED= BootActivator.PLUGIN_ID+".customised";
+	// ^^^ used to ensure we do not apply our customisations more than once (allows users to change the preference
+	// by themselves and not have us repeatedly return it back to our own default setting.
+
+	@Override
+	public void earlyStartup() {
+		try {
+			IEclipsePreferences prefs = InstanceScope.INSTANCE.getNode(M2E_APT_PLUGIN_ID);
+			if (!prefs.getBoolean(PREF_STS_CUSTONISATIONS_APPLIED, false)) {
+			    prefs.put(PREF_MODE, "jdt_apt");
+				prefs.putBoolean(PREF_STS_CUSTONISATIONS_APPLIED, true);
+			}
+			prefs.flush();
+		} catch (BackingStoreException e) {
+			Log.log(e);
+		}
+	}
+}

eclipse-language-servers/org.springsource.ide.eclipse.commons.frameworks.core/src/org/springsource/ide/eclipse/commons/frameworks/core/workspace/ClasspathListenerManager.java

@@ -10,6 +10,10 @@
  *******************************************************************************/
 package org.springsource.ide.eclipse.commons.frameworks.core.workspace;
 
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.resources.ResourcesPlugin;
 import org.eclipse.core.runtime.CoreException;
@@ -37,6 +41,8 @@ public interface ClasspathListener {
 
 	private class MyListener implements IElementChangedListener {
 
+		private Set<String> knownProjectNames = Collections.synchronizedSet(new HashSet<>());
+
 		//@Override
 		public void elementChanged(ElementChangedEvent event) {
 			visit(event.getDelta());
@@ -49,15 +55,20 @@ private void visit(IJavaElementDelta delta) {
 				visitChildren(delta);
 				break;
 			case IJavaElement.JAVA_PROJECT:
-				if (isClasspathChanged(delta.getFlags())) {
-					listener.classpathChanged((IJavaProject)el);
+				IJavaProject jp = (IJavaProject) el;
+				if (isNewProject(jp) || isClasspathChanged(delta.getFlags())) {
+					listener.classpathChanged(jp);
 				}
 				break;
 			default:
 				break;
 			}
 		}
 
+		private boolean isNewProject(IJavaProject jp) {
+			return knownProjectNames.add(jp.getElementName());
+		}
+
 		private boolean isClasspathChanged(int flags) {
 			return 0!= (flags & (
 					IJavaElementDelta.F_CLASSPATH_CHANGED |
@@ -70,6 +81,10 @@ public void visitChildren(IJavaElementDelta delta) {
 				visit(c);
 			}
 		}
+
+		public void addKnownProject(IJavaProject jp) {
+			this.knownProjectNames.add(jp.getElementName());
+		}
 	}
 
 	private ClasspathListener listener;
@@ -83,19 +98,21 @@ public void visitChildren(IJavaElementDelta delta) {
 	 */
 	public ClasspathListenerManager(ClasspathListener listener, boolean initialEvent) {
 		this.listener = listener;
+		myListener=new MyListener();
 		if (initialEvent) {
 			for (IProject p : ResourcesPlugin.getWorkspace().getRoot().getProjects()) {
 				try {
 					if (p.isAccessible() && p.hasNature(JavaCore.NATURE_ID)) {
 						IJavaProject jp = JavaCore.create(p);
 						listener.classpathChanged(jp);
+						myListener.addKnownProject(jp);
 					}
 				} catch (CoreException e) {
 					FrameworkCoreActivator.log(e);
 				}
 			}
 		}
-		JavaCore.addElementChangedListener(myListener=new MyListener(), ElementChangedEvent.POST_CHANGE);
+		JavaCore.addElementChangedListener(myListener, ElementChangedEvent.POST_CHANGE);
 	}
 
 	public ClasspathListenerManager(ClasspathListener listener) {