FindUsages for Java step definition implemented

java/java-impl/src/com/intellij/find/findUsages/CustomJavaFindUsagesHandler.java

@@ -0,0 +1,14 @@
+package com.intellij.find.findUsages;
+
+import com.intellij.psi.PsiElement;
+import com.intellij.usageView.UsageInfo;
+import com.intellij.util.Processor;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * User: Andrey.Vokin
+ * Date: 7/26/12
+ */
+public interface CustomJavaFindUsagesHandler {
+  public void processElementUsages(@NotNull final PsiElement element, @NotNull final Processor<UsageInfo> processor, @NotNull final FindUsagesOptions options);
+}

java/java-impl/src/com/intellij/find/findUsages/CustomJavaFindUsagesHandlerProvider.java

@@ -0,0 +1,13 @@
+package com.intellij.find.findUsages;
+
+import com.intellij.openapi.extensions.ExtensionPointName;
+
+/**
+ * User: Andrey.Vokin
+ * Date: 7/26/12
+ */
+public abstract class CustomJavaFindUsagesHandlerProvider {
+  public static final ExtensionPointName<CustomJavaFindUsagesHandlerProvider> EP_NAME = ExtensionPointName.create("com.intellij.findUsages.java.customJavaFindUsagesHandlerProvider");
+
+  public abstract CustomJavaFindUsagesHandler getHandler();
+}

java/java-impl/src/com/intellij/find/findUsages/JavaFindUsagesHandler.java

@@ -384,6 +384,11 @@ public class JavaFindUsagesHandler extends FindUsagesHandler{
       // todo add to fastTrack
       processUsagesInText(element, processor, (GlobalSearchScope)options.searchScope);
     }
+
+    final CustomJavaFindUsagesHandlerProvider[] customJavaFindUsagesHandlerProviders = Extensions.getExtensions(CustomJavaFindUsagesHandlerProvider.EP_NAME);
+    for (CustomJavaFindUsagesHandlerProvider provider : customJavaFindUsagesHandlerProviders) {
+      provider.getHandler().processElementUsages(element, processor, options);
+    }
   }
 
   private static void addAliasingUsages(PomTarget pomTarget, final Processor<UsageInfo> processor, final FindUsagesOptions options) {