Package com.intellij.codeInsight.daemon

Interface LineMarkerProvider

All Known Implementing Classes:

ColorLineMarkerProvider, DocRenderDummyLineMarkerProvider, EditorConfigPreviewMarkerProvider, HtmlLineMarkerProvider, IconLineMarkerProvider, IgnoreDirectoryMarkerProvider, JavaFxRelatedItemLineMarkerProvider, JavaLineMarkerProvider, LineMarkerProviderDescriptor, NonCodeAnnotationsLineMarkerProvider, PyiRelatedItemLineMarkerProvider, PyLineMarkerProvider, PyUserSkeletonsLineMarkerProvider, RecursiveCallLineMarkerProvider, RelatedItemLineMarkerProvider, RunLineMarkerProvider

public interface LineMarkerProvider

See Also:

LineMarkerProviders.EP_NAME, LineMarkerProviderDescriptor, RelatedItemLineMarkerProvider

Method Summary

Modifier and Type	Method and Description
default void	collectSlowLineMarkers(java.util.List<? extends PsiElement> elements, java.util.Collection<? super LineMarkerInfo<?>> result)
LineMarkerInfo<?>	getLineMarkerInfo(PsiElement element) Get line markers for this PsiElement.

Method Detail

getLineMarkerInfo

LineMarkerInfo<?> getLineMarkerInfo(PsiElement element)

Get line markers for this PsiElement.

NOTE for implementers: Please create line marker info for leaf elements only - i.e. the smallest possible elements. For example, instead of returning method marker for PsiMethod, create the marker for the PsiIdentifier which is a name of this method.

More technical details:

Highlighting (specifically, LineMarkersPass) queries all LineMarkerProviders in two passes (for performance reasons):

• first pass for all elements in visible area
• second pass for all the rest elements

If provider returned nothing for both areas, its line markers are cleared.

So imagine a LineMarkerProvider which (incorrectly) written like this:

 
   class MyBadLineMarkerProvider implements LineMarkerProvider {
     public LineMarkerInfo getLineMarkerInfo(PsiElement element) {
       if (element instanceof PsiMethod) { // ACTUALLY DONT!
          return new LineMarkerInfo(element, element.getTextRange(), icon, null,null, alignment);
       }
       else {
         return null;
       }
     }
     ...
   }
 
 

Note that it create LineMarkerInfo for the whole method body. Following will happen when this method is half-visible (e.g. its name is visible but a part of its body isn't):

• the first pass would remove line marker info because the whole PsiMethod isn't visible
• the second pass would try to add line marker info back because LineMarkerProvider was called for the PsiMethod at last

As a result, line marker icon will blink annoyingly. Instead, write this:

 
   class MyGoodLineMarkerProvider implements LineMarkerProvider {
     public LineMarkerInfo getLineMarkerInfo(PsiElement element) {
       if (element instanceof PsiIdentifier &&
           (parent = element.getParent()) instanceof PsiMethod &&
           ((PsiMethod)parent).getMethodIdentifier() == element)) { // aha, we are at method name
            return new LineMarkerInfo(element, element.getTextRange(), icon, null,null, alignment);
       }
       else {
         return null;
       }
     }
     ...
   }
 
 

collectSlowLineMarkers

default void collectSlowLineMarkers(java.util.List<? extends PsiElement> elements,
                                    java.util.Collection<? super LineMarkerInfo<?>> result)