Add EqualsHashCode checkstyle rule

This rule ensures classes that override equals() also override hashCode()
neo4j · May 9, 2016 · 20ef116 · 20ef116
1 parent 0243c24
commit 20ef116
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Showing 6 changed files with 25 additions and 731 deletions.
diff --git a/build/checkstyle.xml b/build/checkstyle.xml
@@ -47,6 +47,7 @@
     <module name="MissingOverride"/>
     <module name="EmptyStatement"/>
     <module name="SuperFinalize"/>
+    <module name="EqualsHashCode"/>
 
   </module>
 

diff --git a/community/shell/src/main/java/org/neo4j/shell/util/json/JSONObject.java b/community/shell/src/main/java/org/neo4j/shell/util/json/JSONObject.java
@@ -125,6 +125,11 @@ protected final Object clone() {
             return this;
         }
 
+        @Override
+        public int hashCode() {
+            return 1;
+        }
+
         /**
          * A Null object is equal to the null value and to itself.
          * @param object    An object to test for nullness.

diff --git a/community/unsafe/src/test/java/org/neo4j/unsafe/impl/internal/dragons/UnsafeUtilTest.java b/community/unsafe/src/test/java/org/neo4j/unsafe/impl/internal/dragons/UnsafeUtilTest.java
@@ -22,6 +22,7 @@
 import org.junit.Test;
 
 import java.nio.ByteBuffer;
+import java.util.Objects;
 
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.isOneOf;
@@ -50,17 +51,30 @@ class Obj
         @Override
         public boolean equals( Object o )
         {
+            if ( this == o )
+            {
+                return true;
+            }
             if ( o == null || getClass() != o.getClass() )
             {
                 return false;
             }
-
             Obj obj = (Obj) o;
-
-            return aByte == obj.aByte && aShort == obj.aShort && Float.compare( obj.aFloat, aFloat ) == 0 &&
-                   aChar == obj.aChar && anInt == obj.anInt && aLong == obj.aLong &&
+            return aBoolean == obj.aBoolean &&
+                   aByte == obj.aByte &&
+                   aShort == obj.aShort &&
+                   Float.compare( obj.aFloat, aFloat ) == 0 &&
+                   aChar == obj.aChar &&
+                   anInt == obj.anInt &&
+                   aLong == obj.aLong &&
                    Double.compare( obj.aDouble, aDouble ) == 0 &&
-                   !(object != null ? !object.equals( obj.object ) : obj.object != null);
+                   Objects.equals( object, obj.object );
+        }
+
+        @Override
+        public int hashCode()
+        {
+            return Objects.hash( aBoolean, aByte, aShort, aFloat, aChar, anInt, aLong, aDouble, object );
         }
     }