camel git commit: Add WeakThreadLocal utility class

[lb...@apache.org]

Repository: camel
Updated Branches:
  refs/heads/master a48ffc0eb -> 0f767091a


Add WeakThreadLocal utility class


Project: http://git-wip-us.apache.org/repos/asf/camel/repo
Commit: http://git-wip-us.apache.org/repos/asf/camel/commit/0f767091
Tree: http://git-wip-us.apache.org/repos/asf/camel/tree/0f767091
Diff: http://git-wip-us.apache.org/repos/asf/camel/diff/0f767091

Branch: refs/heads/master
Commit: 0f767091a65f3e3004d8f4cc6ae7e4a94544fbec
Parents: a48ffc0
Author: lburgazzoli <lb...@gmail.com>
Authored: Tue Dec 13 17:35:58 2016 +0100
Committer: lburgazzoli <lb...@gmail.com>
Committed: Tue Dec 13 17:35:58 2016 +0100

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 .../org/apache/camel/util/WeakThreadLocal.java  | 51 ++++++++++++++++++++
 1 file changed, 51 insertions(+)
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http://git-wip-us.apache.org/repos/asf/camel/blob/0f767091/camel-core/src/main/java/org/apache/camel/util/WeakThreadLocal.java
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diff --git a/camel-core/src/main/java/org/apache/camel/util/WeakThreadLocal.java b/camel-core/src/main/java/org/apache/camel/util/WeakThreadLocal.java
new file mode 100644
index 0000000..58959e8
--- /dev/null
+++ b/camel-core/src/main/java/org/apache/camel/util/WeakThreadLocal.java
@@ -0,0 +1,51 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.camel.util;
+
+import java.lang.ref.WeakReference;
+import java.util.function.Supplier;
+
+public final class WeakThreadLocal<T> implements Supplier<T> {
+    private final ThreadLocal<WeakReference<T>> cache;
+    private final Supplier<T> supplier;
+
+    public WeakThreadLocal(Supplier<T> supplier) {
+        this.cache = new ThreadLocal<>();
+        this.supplier = ObjectHelper.notNull(supplier, "value supplier");
+    }
+
+    @Override
+    public T get() {
+        T value = null;
+        WeakReference<T> ref = cache.get();
+
+        if (ref != null) {
+            value = ref.get();
+        }
+
+        if (value == null) {
+            value = supplier.get();
+            cache.set(new WeakReference<>(value));
+        }
+
+        return value;
+    }
+
+    public static <T> WeakThreadLocal<T> withSupplier(Supplier<T> supplier) {
+        return new WeakThreadLocal<>(supplier);
+    }
+}