removed copy/paste code relating to expiration after write

core/src/main/java/org/jclouds/rest/suppliers/MemoizedRetryOnTimeOutButNotOnAuthorizationExceptionSupplier.java

@@ -18,7 +18,7 @@
  */
 package org.jclouds.rest.suppliers;
 
-import static org.jclouds.util.Suppliers2.memoizeWithExpirationOnAbsoluteInterval;
+import static org.jclouds.util.Suppliers2.memoizeWithExpirationAfterWrite;
 
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicReference;
@@ -54,7 +54,7 @@ public class MemoizedRetryOnTimeOutButNotOnAuthorizationExceptionSupplier<T> imp
    
    public MemoizedRetryOnTimeOutButNotOnAuthorizationExceptionSupplier(
          AtomicReference<AuthorizationException> authException, long seconds, Supplier<T> delegate) {
-      this.delegate = memoizeWithExpirationOnAbsoluteInterval(new RetryOnTimeOutExceptionSupplier<T>(
+      this.delegate = memoizeWithExpirationAfterWrite(new RetryOnTimeOutExceptionSupplier<T>(
             new SetAndThrowAuthorizationExceptionSupplier<T>(delegate, authException)), seconds, TimeUnit.SECONDS);
       this.seconds = seconds;
    }

core/src/main/java/org/jclouds/util/Suppliers2.java

@@ -26,12 +26,14 @@ import java.io.Serializable;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 
-import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Function;
 import com.google.common.base.Objects;
-import com.google.common.base.Preconditions;
 import com.google.common.base.Supplier;
 import com.google.common.base.Suppliers;
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+import com.google.common.collect.ForwardingObject;
 import com.google.common.collect.Iterables;
 import com.google.common.io.OutputSupplier;
 
@@ -57,7 +59,7 @@ public class Suppliers2 {
    }
 
    public static <X> Function<X, Supplier<X>> ofInstanceFunction() {
-      return new Function<X, Supplier<X>>(){
+      return new Function<X, Supplier<X>>() {
 
          @Override
          public Supplier<X> apply(X arg0) {
@@ -65,7 +67,7 @@ public class Suppliers2 {
          }
 
          @Override
-         public String toString(){
+         public String toString() {
             return "Suppliers.ofInstance()";
          }
       };
@@ -85,70 +87,43 @@ public class Suppliers2 {
    }
 
    /**
-    * See Supplier.memoizeWithExpiration.
+    * same as {@link Supplier.memoizeWithExpiration} except that the expiration ticker starts after
+    * write vs after call to {@code get}.
     * 
-    * Difference between this impl and v11.0 is that we fix
+    * @see Supplier.memoizeWithExpiration
-    * http://code.google.com/p/guava-libraries/issues/detail?id=857.
     */
-   public static <T> Supplier<T> memoizeWithExpirationOnAbsoluteInterval(Supplier<T> delegate, long duration,
+   public static <T> Supplier<T> memoizeWithExpirationAfterWrite(Supplier<T> delegate, long duration, TimeUnit unit) {
-            TimeUnit unit) {
+      return new ExpireAfterWriteSupplier<T>(delegate, duration, unit);
-      return new ExpiringMemoizingSupplier<T>(delegate, duration, unit);
    }
 
-   @VisibleForTesting
+   static class ExpireAfterWriteSupplier<T> extends ForwardingObject implements Supplier<T>, Serializable {
-   static class ExpiringMemoizingSupplier<T> implements Supplier<T>, Serializable {
+      private final Supplier<T> delegate;
-      final Supplier<T> delegate;
+      private final long duration;
-      final long durationNanos;
+      private final TimeUnit unit;
-      transient volatile T value;
+      private final LoadingCache<Object, T> cache;
-      // The special value 0 means "not yet initialized".
-      transient volatile long expirationNanos;
 
-      ExpiringMemoizingSupplier(Supplier<T> delegate, long duration, TimeUnit unit) {
+      public ExpireAfterWriteSupplier(Supplier<T> delegate, long duration, TimeUnit unit) {
-         this.delegate = Preconditions.checkNotNull(delegate);
+         this.delegate = delegate;
-         this.durationNanos = unit.toNanos(duration);
+         this.duration = duration;
-         Preconditions.checkArgument(duration > 0);
+         this.unit = unit;
+         cache = CacheBuilder.newBuilder().expireAfterWrite(duration, unit).build(CacheLoader.from(delegate));
+      }
+
+      @Override
+      protected Supplier<T> delegate() {
+         return delegate;
       }
 
       @Override
       public T get() {
-         // Another variant of Double Checked Locking.
+         return cache.getUnchecked("FOO");
-         //
-         // We use two volatile reads. We could reduce this to one by
-         // putting our fields into a holder class, but (at least on x86)
-         // the extra memory consumption and indirection are more
-         // expensive than the extra volatile reads.
-         long nanos = expirationNanos;
-         long now = System.nanoTime();
-         if (nanos == 0 || now - nanos >= 0) {
-            synchronized (this) {
-               if (nanos == expirationNanos) { // recheck for lost race
-
-                  // Set value to null prior to retrieving new val, so old and new are not held in
-                  // memory simultaneously
-                  value = null;
-
-                  T t = delegate.get();
-                  value = t;
-
-                  // Update now so that, if call was expensive, we keep value for the full duration
-                  now = System.nanoTime();
-
-                  nanos = now + durationNanos;
-                  // In the very unlikely event that nanos is 0, set it to 1;
-                  // no one will notice 1 ns of tardiness.
-                  expirationNanos = (nanos == 0) ? 1 : nanos;
-                  return t;
-               }
-            }
-         }
-         return value;
       }
 
       private static final long serialVersionUID = 0;
 
       @Override
       public int hashCode() {
-         return Objects.hashCode(delegate, durationNanos);
+         return Objects.hashCode(delegate, duration, unit);
       }
 
       @Override
@@ -159,13 +134,14 @@ public class Suppliers2 {
             return false;
          if (getClass() != obj.getClass())
             return false;
-         ExpiringMemoizingSupplier<?> that = ExpiringMemoizingSupplier.class.cast(obj);
+         ExpireAfterWriteSupplier<?> that = ExpireAfterWriteSupplier.class.cast(obj);
-         return Objects.equal(delegate, that.delegate) && Objects.equal(durationNanos, that.durationNanos);
+         return Objects.equal(delegate, that.delegate) && Objects.equal(duration, that.duration);
       }
 
       @Override
       public String toString() {
-         return Objects.toStringHelper(this).add("delegate", delegate).add("durationNanos", durationNanos).toString();
+         return Objects.toStringHelper(this).add("delegate", delegate).add("duration", duration).add("unit", unit)
+                  .toString();
       }
 
    }

core/src/test/java/org/jclouds/util/Suppliers2Test.java

@@ -74,7 +74,7 @@ public class Suppliers2Test {
          }
       };
       
-      Supplier<Integer> memoizedSupplier = Suppliers2.memoizeWithExpirationOnAbsoluteInterval(
+      Supplier<Integer> memoizedSupplier = Suppliers2.memoizeWithExpirationAfterWrite(
                slowSupplier, EXPIRATION_TIME, TimeUnit.MILLISECONDS);
       
       assertEquals(memoizedSupplier.get(), (Integer)10);
@@ -100,7 +100,7 @@ public class Suppliers2Test {
     public void testMemoizeWithExpiration() throws InterruptedException {
       CountingSupplier countingSupplier = new CountingSupplier();
 
-      Supplier<Integer> memoizedSupplier = Suppliers2.memoizeWithExpirationOnAbsoluteInterval(
+      Supplier<Integer> memoizedSupplier = Suppliers2.memoizeWithExpirationAfterWrite(
           countingSupplier, 75, TimeUnit.MILLISECONDS);
 
       checkExpiration(countingSupplier, memoizedSupplier);
@@ -111,7 +111,7 @@ public class Suppliers2Test {
         throws InterruptedException {
       CountingSupplier countingSupplier = new CountingSupplier();
 
-      Supplier<Integer> memoizedSupplier = Suppliers2.memoizeWithExpirationOnAbsoluteInterval(
+      Supplier<Integer> memoizedSupplier = Suppliers2.memoizeWithExpirationAfterWrite(
           countingSupplier, 75, TimeUnit.MILLISECONDS);
       // Calls to the original memoized supplier shouldn't affect its copy.
       memoizedSupplier.get();
@@ -120,7 +120,7 @@ public class Suppliers2Test {
       memoizedSupplier.get();
 
       CountingSupplier countingCopy = (CountingSupplier)
-          ((Suppliers2.ExpiringMemoizingSupplier<Integer>) copy).delegate;
+          ((Suppliers2.ExpireAfterWriteSupplier<Integer>) copy).delegate();
       checkExpiration(countingCopy, copy);
     }
 
@@ -154,7 +154,7 @@ public class Suppliers2Test {
       Function<Supplier<Boolean>, Supplier<Boolean>> memoizer =
           new Function<Supplier<Boolean>, Supplier<Boolean>>() {
         @Override public Supplier<Boolean> apply(Supplier<Boolean> supplier) {
-          return Suppliers2.memoizeWithExpirationOnAbsoluteInterval(
+          return Suppliers2.memoizeWithExpirationAfterWrite(
               supplier, Long.MAX_VALUE, TimeUnit.NANOSECONDS);
         }
       };