folding builder style setters (IDEA-86541)

java/java-impl/src/com/intellij/codeInsight/folding/impl/JavaFoldingBuilder.java

@@ -267,7 +267,7 @@ public class JavaFoldingBuilder extends CustomFoldingBuilder implements DumbAwar
     PsiCodeBlock body = method.getBody();
     if (body == null) return false;
     PsiStatement[] statements = body.getStatements();
-    if (statements.length != 1) return false;
+    if (statements.length == 0) return false;
     PsiStatement statement = statements[0];
     if (PropertyUtil.isSimplePropertyGetter(method)) {
       if (statement instanceof PsiReturnStatement) {
@@ -275,6 +275,7 @@ public class JavaFoldingBuilder extends CustomFoldingBuilder implements DumbAwar
       }
     }
     else if (PropertyUtil.isSimplePropertySetter(method)) {
+      if (statements.length > 1 && !(statements[1] instanceof PsiReturnStatement)) return false;
       if (statement instanceof PsiExpressionStatement) {
         PsiExpression expr = ((PsiExpressionStatement)statement).getExpression();
         if (expr instanceof PsiAssignmentExpression) {

java/java-tests/testSrc/com/intellij/codeInsight/folding/JavaFoldingTest.groovy

@@ -168,6 +168,27 @@ class Test {
     assertNotNull closureFolds
     assertEquals(2, closureFolds.size())
   }
+  
+  public void "test builder style setter"() {
+    myFoldingSettings.COLLAPSE_ACCESSORS = true
+    def text = """\
+class Foo {
+    private String bar;
+
+    public Foo setBar(String bar) {
+        this.bar = bar;
+        return this;
+    }
+}
+"""
+
+    configure text
+    def foldingModel = myFixture.editor.foldingModel as FoldingModelImpl
+    int indexOfBar = text.indexOf("this.bar")
+    def accessorStartFold = foldingModel.getCollapsedRegionAtOffset(indexOfBar)
+    assertNotNull accessorStartFold
+    assertFalse accessorStartFold.expanded
+  }
 
   public void "test closure folding doesn't expand when editing inside"() {
     def text = """\