From 02f4a60f0a6c79fb3e3fdbcf325dd9d958083bde Mon Sep 17 00:00:00 2001
From: Mark Perry <maperry78@yahoo.com.au>
Date: Thu, 28 May 2015 21:16:56 +1000
Subject: [PATCH 1/2] Attempt to fix #108

---
 core/src/main/java/fj/P1.java | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/core/src/main/java/fj/P1.java b/core/src/main/java/fj/P1.java
index 5ae82a97..844e4482 100644
--- a/core/src/main/java/fj/P1.java
+++ b/core/src/main/java/fj/P1.java
@@ -9,7 +9,7 @@
 import fj.data.Option;
 import fj.data.Validation;
 //import fj.data.*;
-import fj.function.Try0;
+
 
 public abstract class P1<A> implements F0<A> {
 
@@ -216,22 +216,22 @@ public P1<A> memo() {
         final P1<A> self = this;
         return new P1<A>() {
           private final Object latch = new Object();
-          @SuppressWarnings({"InstanceVariableMayNotBeInitialized"})
-          private volatile SoftReference<A> v;
+          private volatile SoftReference<Option<A>> v = null;
 
           public A _1() {
-            A a = v != null ? v.get() : null;
-            if (a == null)
+            Option<A> o = v != null ? v.get() : null;
+            if (o == null) {
               synchronized (latch) {
-                if (v == null || v.get() == null) {
-                  a = self._1();
-                  v = new SoftReference<A>(a);
-                } else {
-                  a = v.get();
+                o = v != null ? v.get() : null;
+                if (o == null) {
+                  o = Option.some(self._1());
+                  v = new SoftReference<>(o);
                 }
               }
-            return a;
+            }
+            return o.some();
           }
+
         };
       }
 

From b07073d3e013ba347bda51ace61fba0504f9fc54 Mon Sep 17 00:00:00 2001
From: Mark Perry <maperry78@yahoo.com.au>
Date: Thu, 28 May 2015 22:14:32 +1000
Subject: [PATCH 2/2] Override memo for an already memoised P1

---
 core/src/main/java/fj/P1.java | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/core/src/main/java/fj/P1.java b/core/src/main/java/fj/P1.java
index 844e4482..ddb0d04d 100644
--- a/core/src/main/java/fj/P1.java
+++ b/core/src/main/java/fj/P1.java
@@ -218,6 +218,7 @@ public P1<A> memo() {
           private final Object latch = new Object();
           private volatile SoftReference<Option<A>> v = null;
 
+          @Override
           public A _1() {
             Option<A> o = v != null ? v.get() : null;
             if (o == null) {
@@ -232,6 +233,11 @@ public A _1() {
             return o.some();
           }
 
+          @Override
+          public P1<A> memo() {
+              return this;
+          }
+
         };
       }