From 5ed44301c8dfbb6bc5ccdcf345757e2eb2ada52d Mon Sep 17 00:00:00 2001
From: Paul Campbell <pcampbell@kemitix.net>
Date: Tue, 6 Sep 2016 19:01:44 +0100
Subject: [PATCH] EqualsAvoidNull: enabled

---
 README.md                                     | 22 ++++++++++++++-----
 src/main/resources/net/kemitix/checkstyle.xml |  1 +
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index 35c34cb..3386ec4 100644
--- a/README.md
+++ b/README.md
@@ -126,7 +126,7 @@ You need to include `checkstyle` as the version bundled with the `maven-checksty
 * [EmptyPublicCtorInClass](#emptypublicctorinclass) - sevntu - disabled
 * [EmptyStatement](#emptystatement) - checkstyle - enabled
 * [EnumValueName](#enumvaluename) - sevntu - enabled
-* [EqualsAvoidNull](#equalsavoidnull) - checkstyle - disabled
+* [EqualsAvoidNull](#equalsavoidnull) - checkstyle - enabled
 * [EqualsHashCode](#equalshashcode) - checkstyle - enabled
 * [ExecutableStatementCount](#executablestatementcount) - checkstyle - enabled
 * [ExplicitInitialization](#explicitinitialization) - checkstyle - enabled
@@ -918,6 +918,22 @@ Invalid:
 doSomething();;
 ````
 
+#### [EqualsAvoidNull](http://checkstyle.sourceforge.net/config_coding.html#EqualsAvoidNull)
+
+Checks that string literals are on the left side in an `equals()` comparison.
+
+Valid:
+````
+String nullString = null;
+"value".equals(nullString);
+````
+
+Invalid:
+````
+String nullString = null;
+nullString.equals("value");
+````
+
 #### [EqualsHashCode](http://checkstyle.sourceforge.net/config_coding.html#EqualsHashCode)
 
 Checks that when a class overrides the `equals()` method, that it also overrides the `hashCode()` method.
@@ -2613,10 +2629,6 @@ These checks are not enabled. Notes are included for each explaining why.
 
 Couldn't get my IDE's (IntelliJ) code style to match.
 
-#### [EqualsAvoidNull](http://checkstyle.sourceforge.net/config_coding.html#EqualsAvoidNull)
-
-> TODO: enable
-
 #### [FinalLocalVariable](http://checkstyle.sourceforge.net/config_coding.html#FinalLocalVariable)
 
 > TODO: enable
diff --git a/src/main/resources/net/kemitix/checkstyle.xml b/src/main/resources/net/kemitix/checkstyle.xml
index 459fa79..47e8301 100644
--- a/src/main/resources/net/kemitix/checkstyle.xml
+++ b/src/main/resources/net/kemitix/checkstyle.xml
@@ -74,6 +74,7 @@
         <module name="EmptyForIteratorPad"/> <!-- empty for loop iterator muse have have no spaces -->
         <module name="EmptyLineSeparator"/> <!-- enforce blank lines after header, fields, constructors, methods, etc -->
         <module name="EmptyStatement"/> <!-- prevent standalone ";" semicolons -->
+        <module name="EqualsAvoidNull"/> <!-- prevents v = null; v.equals("..") -->
         <module name="EqualsHashCode"/> <!-- if equals() is overridden then so must hashCode() be -->
         <module name="ExecutableStatementCount"/> <!-- limit executable statements to 30 per method -->
         <module name="ExplicitInitialization"/> <!-- avoid initializing a field twice to the same value -->