Added support for hex float and double constants.

src/checkstyle/com/puppycrawl/tools/checkstyle/grammars/java.g

@@ -1784,6 +1784,8 @@ NUM_INT
       |   (DOT)=>DOT {$setType(DOT);}
       |   (DOUBLE_LITERAL)=>DOUBLE_LITERAL {$setType(NUM_DOUBLE);}
       |   (FLOAT_LITERAL)=>FLOAT_LITERAL {$setType(NUM_FLOAT);}
+      |   (HEX_DOUBLE_LITERAL)=>HEX_DOUBLE_LITERAL {$setType(NUM_DOUBLE);}
+      |   (HEX_FLOAT_LITERAL)=>HEX_FLOAT_LITERAL {$setType(NUM_FLOAT);}
       |   (LONG_LITERAL)=>LONG_LITERAL {$setType(NUM_LONG);}
       |   (INT_LITERAL)=>INT_LITERAL {$setType(NUM_INT);}
       ;
@@ -1834,6 +1836,32 @@ protected DOUBLE_LITERAL
         (EXPONENT)? ('d'|'D')
     ;
 
+protected HEX_FLOAT_LITERAL
+    :   '0' ('x'|'X')
+        (
+            ((HEX_DIGIT)* '.')=>
+            (   (HEX_DIGIT)+ '.' (HEX_DIGIT)*
+            |   '.' (HEX_DIGIT)+
+            )
+        |
+            (HEX_DIGIT)+
+        )
+        BINARY_EXPONENT ('f'|'F')?
+    ;
+
+protected HEX_DOUBLE_LITERAL
+    :   '0' ('x'|'X')
+        (
+            ((HEX_DIGIT)* '.')=>
+            (   (HEX_DIGIT)+ '.' (HEX_DIGIT)*
+            |   '.' (HEX_DIGIT)+
+            )
+        |
+            (HEX_DIGIT)+
+        )
+        BINARY_EXPONENT ('d'|'D')
+    ;
+
 protected ELLIPSIS
     :   ".."
     ;
@@ -1845,10 +1873,20 @@ protected DOT
 // a couple protected methods to assist in matching floating point numbers
 protected
 EXPONENT
-	:	('e'|'E') ('+'|'-')? ('0'..'9')+
+	:	('e'|'E') SIGNED_INTEGER
 	;
 
+protected
+SIGNED_INTEGER
+    :   ('+'|'-')? ('0'..'9')+
+    ;
+
 protected
 FLOAT_SUFFIX
 	:	'f'|'F'|'d'|'D'
 	;
+
+protected
+BINARY_EXPONENT
+    :   ('p'|'P') SIGNED_INTEGER
+    ;

src/testinputs/com/puppycrawl/tools/checkstyle/grammars/InputHexFloat.java

@@ -0,0 +1,16 @@
+package com.puppycrawl.tools.checkstyle.grammars;
+
+/**
+ * Input for hex float and double test.
+ */
+public class InputHexFloat
+{
+    float f1 = 0x.0P10;
+    float f2 = 0x1.P-1;
+    float f3 = 0Xab1P0;
+    float f4 = 0Xab1ap+20;
+    float f5 = 0Xab1ap+20D;
+    float f6 = 0Xab1ap+20d;
+    float f5 = 0Xab1ap+20f;
+    float f6 = 0Xab1ap+20F;
+}

src/tests/com/puppycrawl/tools/checkstyle/grammars/AllTests.java

@@ -16,6 +16,7 @@ public class AllTests {
         //$JUnit-BEGIN$
         suite.addTest(new TestSuite(GeneratedJava14LexerTest.class));
         suite.addTest(new TestSuite(Post13KeywordsAsIdentifiersOKTest.class));
+        suite.addTest(new TestSuite(HexFloatsTest.class));
         //$JUnit-END$
         return suite;
     }

src/tests/com/puppycrawl/tools/checkstyle/grammars/HexFloatsTest.java

@@ -0,0 +1,23 @@
+package com.puppycrawl.tools.checkstyle.grammars;
+
+import com.puppycrawl.tools.checkstyle.BaseCheckTestCase;
+import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
+import com.puppycrawl.tools.checkstyle.checks.naming.MemberNameCheck;
+
+/**
+ * Tests hex floats and doubles can be parsed.
+ * @author Michael Studman
+ */
+public class HexFloatsTest
+    extends BaseCheckTestCase
+{
+    public void testCanParse()
+        throws Exception
+
+    {
+        final DefaultConfiguration checkConfig =
+            createCheckConfig(MemberNameCheck.class);
+        final String[] expected = {};
+        verify(checkConfig, getPath("grammars/InputHexFloat.java"), expected);
+    }
+}