Equal.equals0: helper method to implements Object.equals. Fix functionaljava#122

jbgi · jbgi · commit 91dc69007ccd · 2015-04-11T15:16:21.000+02:00
diff --git a/core/src/main/java/fj/Equal.java b/core/src/main/java/fj/Equal.java
@@ -1,6 +1,7 @@
 package fj;
 
 import static fj.Function.curry;
+import static fj.Unit.unit;
 
 import fj.data.*;
 import fj.data.hlist.HList;
@@ -549,5 +550,33 @@ public static Option<Boolean> shallowEqualsO(Object o1, Object o2) {
       return Option.some(false);
     }
   }
+  
+  /**
+   * Helper method to implement {@link Object#equals(Object)} correctly. DO NOT USE it for any other purpose.
+   *
+   * @param clazz the class in which the {@link Object#equals(Object)} is implemented
+   * @param self a reference to 'this'
+   * @param other the other object of the comparison
+   * @param equal an equal instance for the type of self (that use {@link #anyEqual()} if generic type).
+   * @return true if self and other are equal
+   */
+  @SuppressWarnings("unchecked")
+  public static <A> boolean equals0(final java.lang.Class<? super A> clazz, final A self, final Object other, final Equal<A> equal) {
+    return self == other ? true : clazz.isInstance(other) ? equal.eq(self, (A) other) : false;
+  }
+  
+  /**
+   * Helper method to implement {@link Object#equals(Object)} correctly. DO NOT USE it for any other purpose.
+   *
+   * @param clazz the class in which the {@link Object#equals(Object)} is implemented
+   * @param self a reference to 'this'
+   * @param other the other object of the comparison
+   * @param equal a lazy equal instance for the type (that use {@link #anyEqual()} if generic type)..
+   * @return true if self and other are equal
+   */
+  @SuppressWarnings("unchecked")
+  public static <A> boolean equals0(final java.lang.Class<? super A> clazz, final A self, final Object other, final F<Unit, Equal<A>> equal) {
+    return self == other ? true : clazz.isInstance(other) ? equal.f(unit()).eq(self, (A) other) : false;
+  }
 
 }
diff --git a/core/src/main/java/fj/P1.java b/core/src/main/java/fj/P1.java
@@ -254,10 +254,9 @@ public String toString() {
 		return Show.p1Show(Show.<A>anyShow()).showS(this);
 	}
 
-    @SuppressWarnings("unchecked")
     @Override
     public boolean equals(Object other) {
-        return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.p1Equal(Equal.<A>anyEqual()).eq(this, (P1<A>) other)));
+        return Equal.equals0(P1.class, this, other, u -> Equal.p1Equal(Equal.<A>anyEqual()));
     }
 
     @Override
diff --git a/core/src/main/java/fj/P2.java b/core/src/main/java/fj/P2.java
@@ -26,7 +26,7 @@ public abstract class P2<A, B> {
 
   @Override
   public boolean equals(Object other) {
-    return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.p2Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual()).eq(this, (P2<A, B>) other)));
+    return Equal.equals0(P2.class, this, other, u -> Equal.p2Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual()));
   }
 
   @Override
diff --git a/core/src/main/java/fj/P3.java b/core/src/main/java/fj/P3.java
@@ -192,7 +192,8 @@ public String toString() {
 
   @Override
   public boolean equals(Object other) {
-    return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.p3Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual()).eq(this, (P3<A, B, C>) other)));
+    return Equal.equals0(P3.class, this, other, 
+        u -> Equal.p3Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual()));
   }
 
   @Override
diff --git a/core/src/main/java/fj/P4.java b/core/src/main/java/fj/P4.java
@@ -265,7 +265,8 @@ public String toString() {
 
   @Override
   public boolean equals(Object other) {
-    return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.p4Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual(), Equal.<D>anyEqual()).eq(this, (P4<A, B, C, D>) other)));
+    return Equal.equals0(P4.class, this, other,
+        u -> Equal.p4Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual(), Equal.<D>anyEqual()));
   }
 
   @Override
diff --git a/core/src/main/java/fj/P5.java b/core/src/main/java/fj/P5.java
@@ -344,7 +344,8 @@ public String toString() {
 
   @Override
   public boolean equals(Object other) {
-    return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.p5Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual(), Equal.<D>anyEqual(), Equal.<E>anyEqual()).eq(this, (P5<A, B, C, D, E>) other)));
+    return Equal.equals0(P5.class, this, other,
+        u -> Equal.p5Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual(), Equal.<D>anyEqual(), Equal.<E>anyEqual()));
   }
 
   @Override
diff --git a/core/src/main/java/fj/P6.java b/core/src/main/java/fj/P6.java
@@ -435,7 +435,8 @@ public String toString() {
 
   @Override
   public boolean equals(Object other) {
-    return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.p6Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual(), Equal.<D>anyEqual(), Equal.<E>anyEqual(), Equal.<F>anyEqual()).eq(this, (P6<A, B, C, D, E, F>) other)));
+    return Equal.equals0(P6.class, this, other,
+        u -> Equal.p6Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual(), Equal.<D>anyEqual(), Equal.<E>anyEqual(), Equal.<F>anyEqual()));
   }
 
   @Override
diff --git a/core/src/main/java/fj/P7.java b/core/src/main/java/fj/P7.java
@@ -529,7 +529,8 @@ public String toString() {
 
   @Override
   public boolean equals(Object other) {
-    return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.p7Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual(), Equal.<D>anyEqual(), Equal.<E>anyEqual(), Equal.<F>anyEqual(), Equal.<G>anyEqual()).eq(this, (P7<A, B, C, D, E, F, G>) other)));
+    return Equal.equals0(P7.class, this, other,
+        u -> Equal.p7Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual(), Equal.<D>anyEqual(), Equal.<E>anyEqual(), Equal.<F>anyEqual(), Equal.<G>anyEqual()));
   }
 
   @Override
diff --git a/core/src/main/java/fj/P8.java b/core/src/main/java/fj/P8.java
@@ -635,7 +635,8 @@ public String toString() {
 
   @Override
   public boolean equals(Object other) {
-    return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.p8Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual(), Equal.<D>anyEqual(), Equal.<E>anyEqual(), Equal.<F>anyEqual(), Equal.<G>anyEqual(), Equal.<H>anyEqual()).eq(this, (P8<A, B, C, D, E, F, G, H>) other)));
+    return Equal.equals0(P8.class, this, other,
+        u -> Equal.p8Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual(), Equal.<D>anyEqual(), Equal.<E>anyEqual(), Equal.<F>anyEqual(), Equal.<G>anyEqual(), Equal.<H>anyEqual()));
   }
 
   @Override
diff --git a/core/src/main/java/fj/data/Array.java b/core/src/main/java/fj/data/Array.java
@@ -682,7 +682,7 @@ public boolean exists(final F<A, Boolean> f) {
 
   @Override
   public boolean equals(Object o) {
-    return Equal.shallowEqualsO(this, o).orSome(P.lazy(u -> Equal.arrayEqual(Equal.<A>anyEqual()).eq(this, (Array<A>) o)));
+    return Equal.equals0(Array.class, this, o, u -> Equal.arrayEqual(Equal.<A>anyEqual()));
   }
 
   /**
diff --git a/core/src/main/java/fj/data/Either.java b/core/src/main/java/fj/data/Either.java
@@ -94,7 +94,7 @@ public final <X, Y> Either<X, Y> bimap(final F<A, X> left, final F<B, Y> right)
   @Override
   public boolean equals(Object other) {
 
-    return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.eitherEqual(Equal.<A>anyEqual(), Equal.<B>anyEqual()).eq(this, (Either<A, B>) other)));
+    return Equal.equals0(Either.class, this, other, u -> Equal.eitherEqual(Equal.<A>anyEqual(), Equal.<B>anyEqual()));
   }
 
   @Override
diff --git a/core/src/main/java/fj/data/List.java b/core/src/main/java/fj/data/List.java
@@ -1870,14 +1870,9 @@ private void copy() {
      * @param obj the other object to check for equality against.
      * @return true if this list is equal to the provided argument
      */
-    //Suppress the warning for cast to <code>List<A></code> because the type is checked in the previous line.
-    @SuppressWarnings({ "unchecked" })
     @Override public boolean equals( final Object obj ) {
 
-        //Casting to List<A> here does not cause a runtime exception even if the type arguments don't match.
-        //The cast is done to avoid the compiler warning "raw use of parameterized class 'List'"
-
-        return Equal.shallowEqualsO(this, obj).orSome(P.lazy(u -> Equal.listEqual(Equal.<A>anyEqual()).eq(this, (List<A>) obj)));
+        return Equal.equals0(List.class, this, obj, u -> Equal.listEqual(Equal.<A>anyEqual()));
     }
 
     /**
diff --git a/core/src/main/java/fj/data/Option.java b/core/src/main/java/fj/data/Option.java
@@ -626,7 +626,7 @@ public final boolean exists(final F<A, Boolean> f) {
 
   @Override
   public boolean equals(Object other) {
-    return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.optionEqual(Equal.<A>anyEqual()).eq(this, (Option<A>) other)));
+    return Equal.equals0(Option.class, this, other, u -> Equal.optionEqual(Equal.<A>anyEqual()));
   }
 
   /**
diff --git a/core/src/main/java/fj/data/Seq.java b/core/src/main/java/fj/data/Seq.java
@@ -48,7 +48,7 @@ public static <A> Seq<A> empty() {
   @Override
   public boolean equals(Object other) {
 
-    return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.seqEqual(Equal.<A>anyEqual()).eq(this, (Seq<A>) other)));
+    return Equal.equals0(Seq.class, this, other, u -> Equal.seqEqual(Equal.<A>anyEqual()));
   }
 
   /**
diff --git a/core/src/main/java/fj/data/Set.java b/core/src/main/java/fj/data/Set.java
@@ -142,7 +142,7 @@ public static <A> Set<A> empty(final Ord<A> ord) {
 
   @Override
   public boolean equals(Object other) {
-    return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.setEqual(Equal.<A>anyEqual()).eq(this, (Set<A>) other)));
+    return Equal.equals0(Set.class, this, other, u -> Equal.setEqual(Equal.<A>anyEqual()));
   }
 
   @Override
diff --git a/core/src/main/java/fj/data/Stream.java b/core/src/main/java/fj/data/Stream.java
@@ -1247,7 +1247,7 @@ public final boolean forall(final F<A, Boolean> f) {
 
   @Override
   public boolean equals(Object other) {
-    return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.streamEqual(Equal.<A>anyEqual()).eq(this, (Stream<A>) other)));
+    return Equal.equals0(Stream.class, this, other, u -> Equal.streamEqual(Equal.<A>anyEqual()));
   }
 
   @Override
diff --git a/core/src/main/java/fj/data/Tree.java b/core/src/main/java/fj/data/Tree.java
@@ -261,7 +261,7 @@ private Stream<String> drawTree(final Show<A> s) {
 
   @Override
   public boolean equals(Object other) {
-    return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.treeEqual(Equal.<A>anyEqual()).eq(this, (Tree<A>) other)));
+    return Equal.equals0(Tree.class, this, other, u -> Equal.treeEqual(Equal.<A>anyEqual()));
   }
 
   @Override
diff --git a/core/src/main/java/fj/data/TreeMap.java b/core/src/main/java/fj/data/TreeMap.java
@@ -38,7 +38,7 @@ public static <K, V> TreeMap<K, V> empty(final Ord<K> keyOrd) {
 
   @Override
   public boolean equals(Object other) {
-    return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.treeMapEqual(Equal.<K>anyEqual(), Equal.<V>anyEqual()).eq(this, (TreeMap<K, V>) other)));
+    return Equal.equals0(TreeMap.class, this, other, u -> Equal.treeMapEqual(Equal.<K>anyEqual(), Equal.<V>anyEqual()));
   }
 
   @Override
diff --git a/core/src/main/java/fj/data/Validation.java b/core/src/main/java/fj/data/Validation.java
@@ -252,7 +252,7 @@ public boolean exists(final F<T, Boolean> f) {
 
   @Override
   public boolean equals(Object other) {
-    return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.validationEqual(Equal.<E>anyEqual(), Equal.<T>anyEqual()).eq(this, (Validation<E, T>) other)));
+    return Equal.equals0(Validation.class, this, other, u -> Equal.validationEqual(Equal.<E>anyEqual(), Equal.<T>anyEqual()));
   }
 
   @Override
diff --git a/core/src/test/java/fj/P1Test.java b/core/src/test/java/fj/P1Test.java
@@ -28,4 +28,24 @@ public void bug105() throws Exception {
 
     org.junit.Assert.assertEquals("Race condition in P1.memo()", 0, nullCounter.get());
   }
+  
+  @Test
+  public void bug122() throws Exception {
+    final P1<Integer> p1a = new P1<Integer>() {
+
+      @Override
+      public Integer _1() {
+        return 1;
+      }
+    };
+    final P1<Integer> p1b = new P1<Integer>() {
+
+      @Override
+      public Integer _1() {
+        return 1;
+      }
+    };
+
+    org.junit.Assert.assertTrue(p1a + " and " + p1b + " should be equal by Object.equals", p1a.equals(p1b));
+  }
 }

Original file line number	Diff line number	Diff line change
`@@ -254,10 +254,9 @@ public String toString() {`
`254`	`254`	`return Show.p1Show(Show.<A>anyShow()).showS(this);`
`255`	`255`	`}`
`256`	`256`
`257`		`- @SuppressWarnings("unchecked")`
`258`	`257`	`@Override`
`259`	`258`	`public boolean equals(Object other) {`
`260`		`- return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.p1Equal(Equal.<A>anyEqual()).eq(this, (P1<A>) other)));`
	`259`	`+ return Equal.equals0(P1.class, this, other, u -> Equal.p1Equal(Equal.<A>anyEqual()));`
`261`	`260`	`}`
`262`	`261`
`263`	`262`	`@Override`
Original file line number	Diff line number	Diff line change
`@@ -26,7 +26,7 @@ public abstract class P2<A, B> {`
`26`	`26`
`27`	`27`	`@Override`
`28`	`28`	`public boolean equals(Object other) {`
`29`		`- return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.p2Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual()).eq(this, (P2<A, B>) other)));`
	`29`	`+ return Equal.equals0(P2.class, this, other, u -> Equal.p2Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual()));`
`30`	`30`	`}`
`31`	`31`
`32`	`32`	`@Override`
Original file line number	Diff line number	Diff line change
`@@ -192,7 +192,8 @@ public String toString() {`
`192`	`192`
`193`	`193`	`@Override`
`194`	`194`	`public boolean equals(Object other) {`
`195`		`- return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.p3Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual()).eq(this, (P3<A, B, C>) other)));`
	`195`	`+ return Equal.equals0(P3.class, this, other,`
	`196`	`+ u -> Equal.p3Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual()));`
`196`	`197`	`}`
`197`	`198`
`198`	`199`	`@Override`
Original file line number	Diff line number	Diff line change
`@@ -265,7 +265,8 @@ public String toString() {`
`265`	`265`
`266`	`266`	`@Override`
`267`	`267`	`public boolean equals(Object other) {`
`268`		`- return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.p4Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual(), Equal.<D>anyEqual()).eq(this, (P4<A, B, C, D>) other)));`
	`268`	`+ return Equal.equals0(P4.class, this, other,`
	`269`	`+ u -> Equal.p4Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual(), Equal.<D>anyEqual()));`
`269`	`270`	`}`
`270`	`271`
`271`	`272`	`@Override`
Original file line number	Diff line number	Diff line change
`@@ -344,7 +344,8 @@ public String toString() {`
`344`	`344`
`345`	`345`	`@Override`
`346`	`346`	`public boolean equals(Object other) {`
`347`		`- return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.p5Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual(), Equal.<D>anyEqual(), Equal.<E>anyEqual()).eq(this, (P5<A, B, C, D, E>) other)));`
	`347`	`+ return Equal.equals0(P5.class, this, other,`
	`348`	`+ u -> Equal.p5Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual(), Equal.<D>anyEqual(), Equal.<E>anyEqual()));`
`348`	`349`	`}`
`349`	`350`
`350`	`351`	`@Override`
Original file line number	Diff line number	Diff line change
`@@ -435,7 +435,8 @@ public String toString() {`
`435`	`435`
`436`	`436`	`@Override`
`437`	`437`	`public boolean equals(Object other) {`
`438`		`- return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.p6Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual(), Equal.<D>anyEqual(), Equal.<E>anyEqual(), Equal.<F>anyEqual()).eq(this, (P6<A, B, C, D, E, F>) other)));`
	`438`	`+ return Equal.equals0(P6.class, this, other,`
	`439`	`+ u -> Equal.p6Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual(), Equal.<D>anyEqual(), Equal.<E>anyEqual(), Equal.<F>anyEqual()));`
`439`	`440`	`}`
`440`	`441`
`441`	`442`	`@Override`
Original file line number	Diff line number	Diff line change
`@@ -529,7 +529,8 @@ public String toString() {`
`529`	`529`
`530`	`530`	`@Override`
`531`	`531`	`public boolean equals(Object other) {`
`532`		`- return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.p7Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual(), Equal.<D>anyEqual(), Equal.<E>anyEqual(), Equal.<F>anyEqual(), Equal.<G>anyEqual()).eq(this, (P7<A, B, C, D, E, F, G>) other)));`
	`532`	`+ return Equal.equals0(P7.class, this, other,`
	`533`	`+ u -> Equal.p7Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual(), Equal.<D>anyEqual(), Equal.<E>anyEqual(), Equal.<F>anyEqual(), Equal.<G>anyEqual()));`
`533`	`534`	`}`
`534`	`535`
`535`	`536`	`@Override`
Original file line number	Diff line number	Diff line change
`@@ -635,7 +635,8 @@ public String toString() {`
`635`	`635`
`636`	`636`	`@Override`
`637`	`637`	`public boolean equals(Object other) {`
`638`		`- return Equal.shallowEqualsO(this, other).orSome(P.lazy(u -> Equal.p8Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual(), Equal.<D>anyEqual(), Equal.<E>anyEqual(), Equal.<F>anyEqual(), Equal.<G>anyEqual(), Equal.<H>anyEqual()).eq(this, (P8<A, B, C, D, E, F, G, H>) other)));`
	`638`	`+ return Equal.equals0(P8.class, this, other,`
	`639`	`+ u -> Equal.p8Equal(Equal.<A>anyEqual(), Equal.<B>anyEqual(), Equal.<C>anyEqual(), Equal.<D>anyEqual(), Equal.<E>anyEqual(), Equal.<F>anyEqual(), Equal.<G>anyEqual(), Equal.<H>anyEqual()));`
`639`	`640`	`}`
`640`	`641`
`641`	`642`	`@Override`
Original file line number	Diff line number	Diff line change
`@@ -682,7 +682,7 @@ public boolean exists(final F<A, Boolean> f) {`
`682`	`682`
`683`	`683`	`@Override`
`684`	`684`	`public boolean equals(Object o) {`
`685`		`- return Equal.shallowEqualsO(this, o).orSome(P.lazy(u -> Equal.arrayEqual(Equal.<A>anyEqual()).eq(this, (Array<A>) o)));`
	`685`	`+ return Equal.equals0(Array.class, this, o, u -> Equal.arrayEqual(Equal.<A>anyEqual()));`
`686`	`686`	`}`
`687`	`687`
`688`	`688`	`/**`