autocomplete for build.properties: follow-up (#529)

a few review comments are included in this follow-up PR:
 - removed inheriting from ICompletionListener
 - hence removed completion listener registration
(ICompletionListener.addCompletionListener)
 - usage of array creation shortcut
 - better string initialization
 - localization of fContentAssistantProcessor variable

Refs: #508

ui/org.eclipse.pde.ui/src/org/eclipse/pde/internal/ui/editor/build/BuildSourceViewerConfiguration.java

@@ -43,7 +43,6 @@ public class BuildSourceViewerConfiguration extends ChangeAwareSourceViewerConfi
 	private BasePDEScanner fPropertyValueScanner;
 
 	private ContentAssistant fContentAssistant;
-	private BuildPropertiesContentAssistProcessor fContentAssistantProcessor;
 
 	private abstract class AbstractJavaScanner extends BasePDEScanner {
 
@@ -247,10 +246,9 @@ public IContentAssistant getContentAssistant(ISourceViewer sourceViewer) {
 				PDEPluginImages.get(null);
 				fContentAssistant = new ContentAssistant(true);
 				fContentAssistant.setDocumentPartitioning(getConfiguredDocumentPartitioning(sourceViewer));
-				fContentAssistantProcessor = new BuildPropertiesContentAssistProcessor(fSourcePage);
+				var fContentAssistantProcessor = new BuildPropertiesContentAssistProcessor(fSourcePage);
 				fContentAssistant.setContentAssistProcessor(fContentAssistantProcessor, IDocument.DEFAULT_CONTENT_TYPE);
 				fContentAssistant.setContentAssistProcessor(fContentAssistantProcessor, PROPERTY_VALUE);
-				fContentAssistant.addCompletionListener(fContentAssistantProcessor);
 				fContentAssistant.enableAutoInsert(true);
 				fContentAssistant.setInformationControlCreator(parent -> new DefaultInformationControl(parent, false));
 				fContentAssistant.setContextInformationPopupOrientation(IContentAssistant.CONTEXT_INFO_ABOVE);

ui/org.eclipse.pde.ui/src/org/eclipse/pde/internal/ui/editor/contentassist/BuildPropertiesContentAssistProcessor.java

@@ -15,36 +15,17 @@
 import java.lang.reflect.Field;
 import java.util.ArrayList;
 import org.eclipse.jface.text.*;
-import org.eclipse.jface.text.contentassist.*;
+import org.eclipse.jface.text.contentassist.ICompletionProposal;
 import org.eclipse.pde.internal.build.IBuildPropertiesConstants;
 import org.eclipse.pde.internal.ui.editor.PDESourcePage;
 
-public class BuildPropertiesContentAssistProcessor extends TypePackageCompletionProcessor
-		implements ICompletionListener {
+public class BuildPropertiesContentAssistProcessor extends TypePackageCompletionProcessor {
 
 	protected PDESourcePage fSourcePage;
 	public BuildPropertiesContentAssistProcessor(PDESourcePage sourcePage) {
 		fSourcePage = sourcePage;
 	}
 
-	@Override
-	public void assistSessionStarted(ContentAssistEvent event) {
-		// TODO Auto-generated method stub
-
-	}
-
-	@Override
-	public void assistSessionEnded(ContentAssistEvent event) {
-		// TODO Auto-generated method stub
-
-	}
-
-	@Override
-	public void selectionChanged(ICompletionProposal proposal, boolean smartToggle) {
-		// TODO Auto-generated method stub
-
-	}
-
 	@Override
 	public ICompletionProposal[] computeCompletionProposals(ITextViewer viewer, int offset) {
 		IDocument doc = fSourcePage.getDocumentProvider().getDocument(fSourcePage.getInputContext().getInput());
@@ -56,7 +37,7 @@ public ICompletionProposal[] computeCompletionProposals(ITextViewer viewer, int
 			Field[] properties = IBuildPropertiesConstants.class.getFields();
 			for (Field f : properties) {
 				String key = f.getName();
-				String element = "";
+				String element;
 				try {
 					element = (String) f.get(key);
 				} catch (IllegalAccessException e) {
@@ -68,7 +49,7 @@ public ICompletionProposal[] computeCompletionProposals(ITextViewer viewer, int
 					completions.add(proposal);
 				}
 			}
-			return completions.toArray(new ICompletionProposal[completions.size()]);
+			return completions.toArray(ICompletionProposal[]::new);
 		} catch (BadLocationException e) {
 		}
 		return null;