From b7dbe56df0bc7a0f93c8f761122cf51a996400aa Mon Sep 17 00:00:00 2001
From: "Gregory.Shrago" <gregory.shrago@jetbrains.com>
Date: Fri, 10 Jun 2016 00:16:59 +0300
Subject: [PATCH] lambda expressions breadcrumbs

---
 .../java/JavaBreadcrumbsInfoProvider.java     | 34 ++++++++++++++++---
 1 file changed, 30 insertions(+), 4 deletions(-)

diff --git a/java/java-impl/src/com/intellij/lang/java/JavaBreadcrumbsInfoProvider.java b/java/java-impl/src/com/intellij/lang/java/JavaBreadcrumbsInfoProvider.java
index c645678e1a80..0d374e0db4d6 100644
--- a/java/java-impl/src/com/intellij/lang/java/JavaBreadcrumbsInfoProvider.java
+++ b/java/java-impl/src/com/intellij/lang/java/JavaBreadcrumbsInfoProvider.java
@@ -16,9 +16,8 @@
 package com.intellij.lang.java;
 
 import com.intellij.lang.Language;
-import com.intellij.psi.ElementDescriptionUtil;
-import com.intellij.psi.PsiElement;
-import com.intellij.psi.PsiMember;
+import com.intellij.openapi.util.text.StringUtil;
+import com.intellij.psi.*;
 import com.intellij.refactoring.util.RefactoringDescriptionLocation;
 import com.intellij.usageView.UsageViewShortNameLocation;
 import com.intellij.xml.breadcrumbs.BreadcrumbsInfoProvider;
@@ -37,18 +36,45 @@ public class JavaBreadcrumbsInfoProvider extends BreadcrumbsInfoProvider {
 
   @Override
   public boolean acceptElement(@NotNull PsiElement e) {
-    return e instanceof PsiMember;
+    return e instanceof PsiMember || e instanceof PsiLambdaExpression;
   }
 
   @NotNull
   @Override
   public String getElementInfo(@NotNull PsiElement e) {
+    if (e instanceof PsiLambdaExpression) {
+      PsiType type = ((PsiFunctionalExpression)e).getFunctionalInterfaceType();
+      return type == null ? "<lambda>" : "lambda " + PsiNameHelper.getShortClassName(type.getCanonicalText());
+    }
     return ElementDescriptionUtil.getElementDescription(e, UsageViewShortNameLocation.INSTANCE);
   }
 
   @Nullable
   @Override
   public String getElementTooltip(@NotNull PsiElement e) {
+    if (e instanceof PsiLambdaExpression) return getLambdaDescription((PsiLambdaExpression)e);
     return ElementDescriptionUtil.getElementDescription(e, RefactoringDescriptionLocation.WITH_PARENT);
   }
+
+  @NotNull
+  private static String getLambdaDescription(@NotNull PsiLambdaExpression e) {
+    StringBuilder sb = new StringBuilder("lambda");
+    PsiType functionalInterfaceType = e.getFunctionalInterfaceType();
+    if (functionalInterfaceType != null) {
+      String shortClassName = PsiNameHelper.getShortClassName(functionalInterfaceType.getCanonicalText());
+      sb.append(" ").append(StringUtil.htmlEmphasize(shortClassName));
+    }
+    PsiParameter[] parameters = e.getParameterList().getParameters();
+    if (parameters.length > 0) {
+      sb.append(" (");
+      for (int i = 0; i < parameters.length; i++) {
+        if (i > 0) sb.append(", ");
+        String str = PsiNameHelper.getShortClassName(parameters[i].getType().getCanonicalText());
+        if (str.isEmpty()) str = StringUtil.notNullize(parameters[i].getName());
+        sb.append(StringUtil.htmlEmphasize(str));
+      }
+      sb.append(")");
+    }
+    return sb.toString();
+  }
 }