From 3c0516b86fd237eb75e5843bc845cbb7ed04f0c5 Mon Sep 17 00:00:00 2001
From: albfernandez <infjaf@gmail.com>
Date: Sat, 27 Feb 2016 13:03:41 +0100
Subject: [PATCH] Fix #1340 UseStringBufferForStringAppends False Positive with
 ternary operator (used both in condition and options)

---
 .../UseStringBufferForStringAppendsRule.java    | 15 +++++++++++++++
 .../xml/UseStringBufferForStringAppends.xml     | 17 +++++++++++++++--
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/optimizations/UseStringBufferForStringAppendsRule.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/optimizations/UseStringBufferForStringAppendsRule.java
index fc74c9f453..a3a96a556b 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/optimizations/UseStringBufferForStringAppendsRule.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/optimizations/UseStringBufferForStringAppendsRule.java
@@ -6,6 +6,8 @@ package net.sourceforge.pmd.lang.java.rule.optimizations;
 import net.sourceforge.pmd.lang.ast.Node;
 import net.sourceforge.pmd.lang.java.ast.ASTArgumentList;
 import net.sourceforge.pmd.lang.java.ast.ASTAssignmentOperator;
+import net.sourceforge.pmd.lang.java.ast.ASTConditionalExpression;
+import net.sourceforge.pmd.lang.java.ast.ASTEqualityExpression;
 import net.sourceforge.pmd.lang.java.ast.ASTLocalVariableDeclaration;
 import net.sourceforge.pmd.lang.java.ast.ASTName;
 import net.sourceforge.pmd.lang.java.ast.ASTPrimaryExpression;
@@ -37,6 +39,16 @@ public class UseStringBufferForStringAppendsRule extends AbstractJavaRule {
                 // used in method call
                 continue;
             }
+            ASTEqualityExpression equality = name.getFirstParentOfType(ASTEqualityExpression.class);
+            if (equality != null && equality.getFirstParentOfType(ASTStatementExpression.class) == statement) {
+            	// used in condition
+            	continue;
+            }
+            ASTConditionalExpression conditional = name.getFirstParentOfType(ASTConditionalExpression.class);
+            if (conditional != null && name.jjtGetParent().jjtGetParent().jjtGetParent() == conditional && conditional.getFirstParentOfType(ASTStatementExpression.class) == statement) {
+            	// is used in ternary as only option (not appendend to other string)
+            	continue;
+            }
             if (statement.jjtGetNumChildren() > 0 && statement.jjtGetChild(0) instanceof ASTPrimaryExpression) {
                 ASTName astName = statement.jjtGetChild(0).getFirstDescendantOfType(ASTName.class);
                 if(astName != null){
@@ -47,6 +59,9 @@ public class UseStringBufferForStringAppendsRule extends AbstractJavaRule {
                         }
                     } else if(astName.getImage().equals(name.getImage())){
                         ASTAssignmentOperator assignmentOperator = statement.getFirstDescendantOfType(ASTAssignmentOperator.class);
+                        if (astName.jjtGetParent().jjtGetParent().jjtGetParent().getClass() == ASTEqualityExpression.class) {
+                        	continue;
+                        }                       
                         if (assignmentOperator != null && !assignmentOperator.isCompound()) {
                             addViolation(data, astName);
                         }
diff --git a/pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/optimizations/xml/UseStringBufferForStringAppends.xml b/pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/optimizations/xml/UseStringBufferForStringAppends.xml
index eb055a35a0..48f479e0e7 100644
--- a/pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/optimizations/xml/UseStringBufferForStringAppends.xml
+++ b/pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/optimizations/xml/UseStringBufferForStringAppends.xml
@@ -135,12 +135,25 @@ public class Foo {
      ]]></code>
     </test-code>
     <test-code>
-        <description>#1340 UseStringBufferForStringAppends False Positive with ternary operator</description>
+        <description>#1340 UseStringBufferForStringAppends False Positive with ternary operator (used in condition) </description>
         <expected-problems>0</expected-problems>
         <code><![CDATA[
 public class UseStringBuffer {
     public void foo() {
-        String country = (country == null || "".equals(country))
+        String value = "";
+        country = (value != null) ? "1" : "0";
+    }
+}
+        ]]></code>
+    </test-code>
+    <test-code>
+        <description>#1340 UseStringBufferForStringAppends False Positive with ternary operator (used both in condition and options)</description>
+        <expected-problems>0</expected-problems>
+        <code><![CDATA[
+public class UseStringBuffer {
+    public void foo() {
+        String country = "";
+        country = (country == null || "".equals(country))
                 ? ((String) getCountry())
                 : country;
     }