EP to help ShowImplementationsAction select appropriate psiElement in Find Usages popup

java/java-impl/src/com/intellij/lang/java/JavaUsageToPsiElementProvider.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2000-2010 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.intellij.lang.java;
+
+import com.intellij.lang.Language;
+import com.intellij.psi.PsiClass;
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiField;
+import com.intellij.psi.PsiMethod;
+import com.intellij.psi.impl.source.tree.java.ImportStatementElement;
+import com.intellij.usages.UsageToPsiElementProvider;
+
+/**
+ * @author Konstantin Bulenkov
+ */
+public class JavaUsageToPsiElementProvider extends UsageToPsiElementProvider {
+  private final static Language JAVA = Language.findLanguageByID("JAVA");
+  private final static int MAX_HOPES = 17;
+
+  @Override
+  public PsiElement getAppropriateParentFrom(PsiElement element) {
+    if (element.getLanguage() == JAVA) {
+      int hopes = 0;
+      while (hopes++ < MAX_HOPES && element != null) {
+        if (element instanceof PsiField ||
+            element instanceof PsiMethod ||
+            element instanceof ImportStatementElement ||
+            element instanceof PsiClass
+          ) return element;
+
+        element = element.getParent();
+      }
+    }
+    return null;
+  }
+}

platform/lang-impl/src/com/intellij/find/actions/ShowUsagesAction.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2009 JetBrains s.r.o.
+ * Copyright 2000-2010 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -650,7 +650,8 @@ public class ShowUsagesAction extends AnAction {
             if (usage instanceof UsageInfo2UsageAdapter) {
               final PsiElement element = ((UsageInfo2UsageAdapter)usage).getElement();
               if (element != null) {
-                return element.getContainingFile();
+                final PsiElement view = UsageToPsiElementProvider.findAppropriateParentFrom(element);
+                return view == null ? element : view;
               }
             }
           }

platform/platform-resources/src/META-INF/LangExtensionPoints.xml

@@ -145,6 +145,7 @@
 
   <extensionPoint name="usageTargetProvider"
                   interface="com.intellij.usages.UsageTargetProvider"/>
+  <extensionPoint name="usageToPsiElementProvider" interface="com.intellij.usages.UsageToPsiElementProvider" />
 
   <extensionPoint name="customScopesProvider"
                   interface="com.intellij.psi.search.scope.packageSet.CustomScopesProvider"

platform/usageView/src/com/intellij/usages/UsageToPsiElementProvider.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2000-2010 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.intellij.usages;
+
+import com.intellij.openapi.extensions.ExtensionPointName;
+import com.intellij.psi.PsiElement;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * Used to provide appropriate psiElements from usages in Find Usages popup.
+ * For instance, it's used in Find Usages popup to help ShowImplementationsAction show
+ * psiElement containing a usage
+ *
+ * @author Konstantin Bulenkov
+ */
+public abstract class UsageToPsiElementProvider {
+  public static final ExtensionPointName<UsageToPsiElementProvider> EP_NAME = new ExtensionPointName<UsageToPsiElementProvider>("com.intellij.usageToPsiElementProvider");
+
+  @Nullable
+  public abstract PsiElement getAppropriateParentFrom(PsiElement element);
+
+  @Nullable
+  public static PsiElement findAppropriateParentFrom(@NotNull PsiElement element) {
+    for (UsageToPsiElementProvider provider : EP_NAME.getExtensions()) {
+      final PsiElement parent = provider.getAppropriateParentFrom(element);
+      if (parent != null) {
+        return parent;
+      }
+    }
+    return null;
+  }
+}

resources/src/META-INF/IdeaPlugin.xml

@@ -642,6 +642,7 @@
     <lang.namesValidator language="JAVA" implementationClass="com.intellij.lang.refactoring.JavaNamesValidator"/>
 
     <lang.findUsagesProvider language="JAVA" implementationClass="com.intellij.lang.java.JavaFindUsagesProvider"/>
+    <usageToPsiElementProvider implementation="com.intellij.lang.java.JavaUsageToPsiElementProvider" />
 
     <lang.commenter language="JAVA" implementationClass="com.intellij.lang.java.JavaCommenter"/>