find usages of Kotlin methods in Java code (KT-1819)

#KT-1819 fixed

idea/src/org/jetbrains/jet/plugin/findUsages/KotlinFindFunctionUsagesHandler.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2010-2012 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 org.jetbrains.jet.plugin.findUsages;
+
+import com.intellij.find.findUsages.FindUsagesHandler;
+import com.intellij.psi.PsiCompiledElement;
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiMethod;
+import com.intellij.psi.util.PsiTreeUtil;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.jet.asJava.JetLightClass;
+import org.jetbrains.jet.lang.psi.JetClass;
+import org.jetbrains.jet.lang.psi.JetClassBody;
+import org.jetbrains.jet.lang.psi.JetFunction;
+
+/**
+ * @author yole
+ */
+public class KotlinFindFunctionUsagesHandler extends FindUsagesHandler {
+    protected KotlinFindFunctionUsagesHandler(@NotNull PsiElement psiElement) {
+        super(psiElement);
+    }
+
+    @NotNull
+    @Override
+    public PsiElement[] getSecondaryElements() {
+        JetFunction function = (JetFunction) getPsiElement();
+        if (function.getParent() instanceof JetClassBody) {
+            JetClass containingClass = PsiTreeUtil.getParentOfType(function, JetClass.class);
+            JetLightClass wrapper = JetLightClass.wrapDelegate(containingClass);
+            for (PsiMethod method : wrapper.getMethods()) {
+                if (method instanceof PsiCompiledElement && ((PsiCompiledElement) method).getMirror() == function) {
+                    return new PsiElement[] { method };
+                }
+            }
+        }
+        return PsiElement.EMPTY_ARRAY;
+    }
+}

idea/src/org/jetbrains/jet/plugin/findUsages/KotlinFindUsagesHandlerFactory.java

@@ -21,6 +21,7 @@ import com.intellij.find.findUsages.FindUsagesHandlerFactory;
 import com.intellij.psi.PsiElement;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.jet.lang.psi.JetClass;
+import org.jetbrains.jet.lang.psi.JetFunction;
 
 /**
  * @author yole
@@ -28,11 +29,17 @@ import org.jetbrains.jet.lang.psi.JetClass;
 public class KotlinFindUsagesHandlerFactory extends FindUsagesHandlerFactory {
     @Override
     public boolean canFindUsages(@NotNull PsiElement element) {
-        return element instanceof JetClass;
+        return element instanceof JetClass || element instanceof JetFunction;
     }
 
     @Override
     public FindUsagesHandler createFindUsagesHandler(@NotNull PsiElement element, boolean forHighlightUsages) {
-        return new KotlinFindClassUsagesHandler(element);
+        if (element instanceof JetClass) {
+            return new KotlinFindClassUsagesHandler(element);
+        }
+        if (element instanceof JetFunction) {
+            return new KotlinFindFunctionUsagesHandler(element);
+        }
+        throw new IllegalArgumentException("unexpected element type: " + element);
     }
 }

idea/testData/findUsages/findMethodUsages/Client.java

@@ -0,0 +1,8 @@
+import testing.*;
+
+class Client {
+    public void foo() {
+        Server server = new Server();
+        server.processRequest();
+    }
+}

idea/testData/findUsages/findMethodUsages/Server.kt

@@ -0,0 +1,5 @@
+package testing;
+
+public class Server() {
+    public fun <caret>processRequest() = "foo"
+}

idea/tests/org/jetbrains/jet/findUsages/JetFindUsagesTest.java

@@ -17,12 +17,14 @@
 package org.jetbrains.jet.findUsages;
 
 import com.intellij.psi.PsiField;
+import com.intellij.psi.PsiStatement;
 import com.intellij.psi.util.PsiTreeUtil;
 import com.intellij.testFramework.LightProjectDescriptor;
 import com.intellij.testFramework.fixtures.LightCodeInsightFixtureTestCase;
 import com.intellij.usageView.UsageInfo;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.jet.lang.psi.JetClass;
+import org.jetbrains.jet.lang.psi.JetFunction;
 import org.jetbrains.jet.plugin.JetLightProjectDescriptor;
 import org.jetbrains.jet.plugin.PluginTestCaseBase;
 
@@ -53,4 +55,14 @@ public class JetFindUsagesTest extends LightCodeInsightFixtureTestCase {
         final PsiField field = PsiTreeUtil.getParentOfType(first.getElement(), PsiField.class);
         assertEquals("private Server myServer;", field.getText());
     }
+
+    public void testFindMethodUsages() {
+        myFixture.configureByFiles("findMethodUsages/Server.kt", "findMethodUsages/Client.java");
+        JetFunction function = PsiTreeUtil.getParentOfType(myFixture.getElementAtCaret(), JetFunction.class, false);
+        final Collection<UsageInfo> usages = myFixture.findUsages(function);
+        assertEquals(1, usages.size());
+        UsageInfo first = usages.iterator().next();
+        final PsiStatement stmt = PsiTreeUtil.getParentOfType(first.getElement(), PsiStatement.class);
+        assertEquals("server.processRequest();", stmt.getText());
+    }
 }