add PositionLiteralsFirstInCaseInsensitiveComparisons rule

most of this rule is the same as PositionLiteralsFirstInComparisons

pmd/src/main/resources/rulesets/java/design.xml

@@ -1173,6 +1173,54 @@ class Foo {
   </example>
 </rule>
 
+
+<rule name="PositionLiteralsFirstInCaseInsensitiveComparisons"
+        language="java"
+  since="???"
+  message="Position literals first in String comparisons for EqualsIgnoreCase"
+  class="net.sourceforge.pmd.lang.rule.XPathRule"
+  externalInfoUrl="${pmd.website.baseurl}/rules/java/design.html#PositionLiteralsFirstInComparisons">
+  <description>
+Position literals first in comparisons, if the second argument is null then NullPointerExceptions 
+can be avoided, they will just return false.
+  </description>
+  <priority>3</priority>
+  <properties>
+      <property name="xpath">
+          <value>
+              <![CDATA[
+//PrimaryExpression[
+        PrimaryPrefix[Name
+                [
+    (ends-with(@Image, '.equalsIgnoreCase'))
+                ]
+        ]
+        [
+                   (../PrimarySuffix/Arguments/ArgumentList/Expression/PrimaryExpression/PrimaryPrefix/Literal)
+    and
+    ( count(../PrimarySuffix/Arguments/ArgumentList/Expression) = 1 )
+        ]
+]
+[not(ancestor::Expression/ConditionalAndExpression//EqualityExpression[@Image='!=']//NullLiteral)]
+[not(ancestor::Expression/ConditionalOrExpression//EqualityExpression[@Image='==']//NullLiteral)]
+
+          ]]>
+          </value>
+      </property>
+  </properties>
+  <example>
+<![CDATA[
+class Foo {
+  boolean bar(String x) {
+    return x.equalsIgnoreCase("2"); // should be "2".equalsIgnoreCase(x)
+  }
+}
+
+]]>
+  </example>
+</rule>
+
+
     <rule name="UnnecessaryLocalBeforeReturn"
           since="3.3"
           message="Consider simply returning the value vs storing it in local variable ''{0}''"