Added KotlinSignatureAnnotation wrapper class, and added it into PsiMethodWrapper.

compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/PsiMethodWrapper.java

@@ -24,6 +24,7 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.lang.resolve.java.kt.JetConstructorAnnotation;
 import org.jetbrains.jet.lang.resolve.java.kt.JetMethodAnnotation;
+import org.jetbrains.jet.lang.resolve.java.kt.KotlinSignatureAnnotation;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -73,6 +74,15 @@ public class PsiMethodWrapper extends PsiMemberWrapper {
         return jetConstructor;
     }
 
+    private KotlinSignatureAnnotation signatureAnnotation;
+    @NotNull
+    public KotlinSignatureAnnotation getSignatureAnnotation() {
+        if (signatureAnnotation == null) {
+            signatureAnnotation = KotlinSignatureAnnotation.get(getPsiMethod());
+        }
+        return signatureAnnotation;
+    }
+
     public boolean isAbstract() {
         return psiMember.hasModifierProperty(PsiModifier.ABSTRACT);
     }

compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/kt/KotlinSignatureAnnotation.java

@@ -0,0 +1,47 @@
+/*
+ * 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.lang.resolve.java.kt;
+
+import com.intellij.psi.PsiAnnotation;
+import com.intellij.psi.PsiMethod;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.jetbrains.jet.lang.resolve.java.JvmStdlibNames;
+
+/**
+ * @author Evgeny Gerashchenko
+ * @since 6/1/12
+ */
+public class KotlinSignatureAnnotation extends PsiAnnotationWrapper {
+    public KotlinSignatureAnnotation(@Nullable PsiAnnotation psiAnnotation) {
+        super(psiAnnotation);
+    }
+
+    private String signature;
+
+    public String signature() {
+        if (signature == null) {
+            signature = getStringAttribute(JvmStdlibNames.KOTLIN_SIGNATURE_VALUE_METHOD, "");
+        }
+        return signature;
+    }
+
+    @NotNull
+    public static KotlinSignatureAnnotation get(PsiMethod psiClass) {
+        return new KotlinSignatureAnnotation(psiClass.getModifierList().findAnnotation(JvmStdlibNames.KOTLIN_SIGNATURE.getFqName().getFqName()));
+    }
+}