1 files changed, 38 insertions, 0 deletions
diff --git a/vespajlib/src/main/java/com/yahoo/yolean/concurrent/ResourcePool.java b/vespajlib/src/main/java/com/yahoo/yolean/concurrent/ResourcePool.java
new file mode 100644
index 00000000000..ffc761ad625
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+++ b/vespajlib/src/main/java/com/yahoo/yolean/concurrent/ResourcePool.java
@@ -0,0 +1,38 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.yolean.concurrent;
+
+import java.util.ArrayDeque;
+import java.util.Deque;
+import java.util.Iterator;
+import java.util.function.Supplier;
+
+/**
+ * <p>This implements a simple stack based resource pool. If you are out of resources new are allocated from the
+ * factory.</p>
+ *
+ * @author baldersheim
+ * @since 5.2
+ */
+public final class ResourcePool<T> implements Iterable<T> {
+
+    private final Deque<T> pool = new ArrayDeque<>();
+    private final Supplier<T> factory;
+
+
+    public ResourcePool(Supplier<T> factory) {
+        this.factory = factory;
+    }
+
+    public T alloc() {
+        return pool.isEmpty() ? factory.get() : pool.pop();
+    }
+
+    public void free(T e) {
+        pool.push(e);
+    }
+
+    @Override
+    public Iterator<T> iterator() {
+        return pool.iterator();
+    }
+}