FORGE-995 Modified the equals and hashcode generator.

This is an API breaking change due to the introduction of a new parameter in the method.

Author: VineetReynolds

api/src/main/java/org/jboss/forge/parser/java/util/Refactory.java

@@ -44,23 +44,56 @@ public static void createGetterAndSetter(final JavaClass clazz, final Field<Java
       }
    }
 
-   public static void createHashCodeAndEquals(final JavaClass clazz)
+   public static void createHashCodeAndEquals(final JavaClass clazz, final Field<?>... fields)
    {
+      if(fields == null || fields.length < 1)
+      {
+         throw new IllegalArgumentException("fields cannot be null or empty.");
+      }
+      
+      StringBuilder fieldEqualityChecks = new StringBuilder();
+      StringBuilder hashCodeComputation = new StringBuilder();
+      for (Field<?> field : fields)
+      {
+         String fieldName = field.getName();
+
+         if (field.isPrimitive())
+         {
+            fieldEqualityChecks.append("if (").append(fieldName).append(" != that.").append(fieldName).append(") { ");
+            fieldEqualityChecks.append(" return false;");
+            fieldEqualityChecks.append("} ");
+            
+            hashCodeComputation.append("result = prime * result + ").append(fieldName).append(";");
+         }
+         else
+         {
+            fieldEqualityChecks.append("if (").append(fieldName).append(" != null) { ");
+            fieldEqualityChecks.append(" return ").append(fieldName).append(".equals(((");
+            fieldEqualityChecks.append(clazz.getName());
+            fieldEqualityChecks.append(") that).").append(fieldName);
+            fieldEqualityChecks.append("); } ");
+
+            hashCodeComputation.append("result = prime * result + ((").append(fieldName).append(" == null) ? 0 : ")
+                     .append(fieldName).append(".hashCode());");
+         }
+      }
+      
       clazz.addMethod(
                "public boolean equals(Object that) { " +
                         "if (this == that) { return true; } " +
                         "if (that == null) { return false; } " +
                         "if (getClass() != that.getClass()) { return false; } " +
-                        "if (id != null) { return id.equals((("
-                        + clazz.getName() + ") that).id); } " +
-                        "return super.equals(that); " +
+                        fieldEqualityChecks.toString() +
+                        "return true; " +
                         "}")
                .addAnnotation(Override.class);
 
       clazz.addMethod(
                "public int hashCode() { " +
-                        "if (id != null) { return id.hashCode(); } " +
-                        "return super.hashCode(); }")
+                        "final int prime = 31;" +
+                        "int result = 1;" +
+                        hashCodeComputation.toString() +
+                        "return result; }")
                .addAnnotation(Override.class);
    }
 

impl/src/test/java/org/jboss/forge/test/parser/java/util/RefactoryTest.java

@@ -8,7 +8,9 @@
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
+import static org.junit.matchers.JUnitMatchers.containsString;
 
 import java.util.List;
 
@@ -106,4 +108,47 @@ public void testCreateToStringFromFields() throws Exception
       assertTrue(javaClass.getMethod("toString").getBody().contains("return"));
       assertTrue(javaClass.getMethod("toString").getBody().contains("firstName != null"));
    }
+   
+   @Test
+   public void testCreateHashCodeAndEquals() throws Exception
+   {
+      Field<JavaClass> field = javaClass.getField("foo");
+      Refactory.createHashCodeAndEquals(javaClass, field);
+
+      List<Method<JavaClass>> methods = javaClass.getMethods();
+      Method<JavaClass> equals = methods.get(0);
+      Method<JavaClass> hashcode = methods.get(1);
+
+      assertEquals("equals", equals.getName());
+      assertEquals(1, equals.getParameters().size());
+      assertThat(equals.getBody(), containsString("if (foo != that.foo) {\n  return false;\n}"));
+      
+      assertEquals("hashCode", hashcode.getName());
+      assertEquals(0, hashcode.getParameters().size());
+      assertEquals("int", hashcode.getReturnType());
+      assertThat(hashcode.getBody(), containsString("result=prime * result + foo;"));
+   }
+   
+   @Test
+   public void testCreateHashCodeAndEqualsMultipleFields() throws Exception
+   {
+      Field<JavaClass> intField = javaClass.getField("foo");
+      Field<JavaClass> stringField = javaClass.getField("firstName");
+      Refactory.createHashCodeAndEquals(javaClass, intField, stringField);
+
+      List<Method<JavaClass>> methods = javaClass.getMethods();
+      Method<JavaClass> equals = methods.get(0);
+      Method<JavaClass> hashcode = methods.get(1);
+
+      assertEquals("equals", equals.getName());
+      assertEquals(1, equals.getParameters().size());
+      assertThat(equals.getBody(), containsString("if (foo != that.foo) {\n  return false;\n}"));
+      assertThat(equals.getBody(), containsString("if (firstName != null) {\n  return firstName.equals(((Foo)that).firstName);\n}"));
+      
+      assertEquals("hashCode", hashcode.getName());
+      assertEquals(0, hashcode.getParameters().size());
+      assertEquals("int", hashcode.getReturnType());
+      assertThat(hashcode.getBody(), containsString("result=prime * result + foo;"));
+      assertThat(hashcode.getBody(), containsString("result=prime * result + ((firstName == null) ? 0 : firstName.hashCode());"));
+   }
 }