From c9bfccc35345ce58fb5774d4b0b6a9868b262c0a Mon Sep 17 00:00:00 2001
From: giorgio <giorgio@13f79535-47bb-0310-9956-ffa450edef68>
Date: Wed, 5 Sep 2012 08:31:30 +0000
Subject: git-svn-id: http://svn.us.apache.org/repos/asf/tuscany@1381061
 13f79535-47bb-0310-9956-ffa450edef68

---
 .../components/cache/partitioner.cpp               | 143 +++++++++++++++++++++
 1 file changed, 143 insertions(+)
 create mode 100644 sca-cpp/branches/lightweight-sca/components/cache/partitioner.cpp

(limited to 'sca-cpp/branches/lightweight-sca/components/cache/partitioner.cpp')

diff --git a/sca-cpp/branches/lightweight-sca/components/cache/partitioner.cpp b/sca-cpp/branches/lightweight-sca/components/cache/partitioner.cpp
new file mode 100644
index 0000000000..e3f04ba112
--- /dev/null
+++ b/sca-cpp/branches/lightweight-sca/components/cache/partitioner.cpp
@@ -0,0 +1,143 @@
+/*
+ * 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.
+ */
+
+/* $Rev$ $Date$ */
+
+/**
+ * A partitioner component implementation which forwards data access requests to a
+ * dynamically selected data store component. The selection is externalized, performed
+ * by a selector component, responsible for selecting the target data store given the
+ * data access request key and a list of references to available data store components.
+ * This pattern can be used for sharding or load balancing for example.
+ */
+
+#define WANT_HTTPD_LOG 1
+#include "string.hpp"
+#include "function.hpp"
+#include "list.hpp"
+#include "value.hpp"
+#include "monad.hpp"
+
+namespace tuscany {
+namespace partitioner {
+
+/**
+ * Return the target partition for a key.
+ */
+const failable<lambda<value(const list<value>&)> > partition(const value& key, const lambda<value(const list<value>&)>& selector, const list<value>& partitions) {
+
+    // Call the selector component to convert the given key to a partition number
+    const value p = selector(mklist<value>("get", key, partitions));
+    if (isNil(p)) {
+        ostringstream os;
+        os << "Couldn't get partition number: " << key;
+        return mkfailure<lambda<value(const list<value>&)> >(str(os), -1, false);
+    }
+    return (const lambda<value(const list<value>&)>)p;
+}
+
+/**
+ * Get an item from a partition.
+ */
+const failable<value> get(const value& key, const lambda<value(const list<value>&)>& selector, const list<value>& partitions) {
+
+    // Select partition
+    const failable<lambda<value(const list<value>&)> > p = partition(key, selector, partitions);
+    if (!hasContent(p))
+        return mkfailure<value>(p);
+
+    // Get from selected partition
+    const value val = content(p)(mklist<value>("get", key));
+    if (isNil(val)) {
+        ostringstream os;
+        os << "Couldn't get entry from partition: " << key;
+        return mkfailure<value>(str(os), 404, false);
+    }
+
+    return val;
+}
+
+/**
+ * Post an item to a partition.
+ */
+const failable<value> post(const value& key, const value& val, const lambda<value(const list<value>&)>& selector, const list<value>& partitions) {
+    const value id = append<value>(key, mklist(mkuuid()));
+
+    // Select partition
+    const failable<lambda<value(const list<value>&)> > p = partition(id, selector, partitions);
+    if (!hasContent(p))
+        return mkfailure<value>(p);
+
+    // Put into select partition
+    content(p)(mklist<value>("put", id, val));
+
+    return id;
+}
+
+/**
+ * Put an item into a partition.
+ */
+const failable<value> put(const value& key, const value& val, const lambda<value(const list<value>&)>& selector, const list<value>& partitions) {
+
+    // Select partition
+    const failable<lambda<value(const list<value>&)> > p = partition(key, selector, partitions);
+    if (!hasContent(p))
+        return mkfailure<value>(p);
+
+    // Put into selected partition
+    content(p)(mklist<value>("put", key, val));
+
+    return value(true);
+}
+
+/**
+ * Delete an item from a partition.
+ */
+const failable<value> del(const value& key, const lambda<value(const list<value>&)>& selector, const list<value>& partitions) {
+
+    // Select partition
+    const failable<lambda<value(const list<value>&)> > p = partition(key, selector, partitions);
+    if (!hasContent(p))
+        return mkfailure<value>(p);
+
+    // Delete from selected partition
+    content(p)(mklist<value>("delete", key));
+
+    return value(true);
+}
+
+}
+}
+
+extern "C" {
+
+const tuscany::value apply(const tuscany::list<tuscany::value>& params) {
+    const tuscany::value func(car(params));
+    if (func == "get")
+        return tuscany::partitioner::get(cadr(params), caddr(params), cdddr(params));
+    if (func == "post")
+        return tuscany::partitioner::post(cadr(params), caddr(params), cadddr(params), cddddr(params));
+    if (func == "put")
+        return tuscany::partitioner::put(cadr(params), caddr(params), cadddr(params), cddddr(params));
+    if (func == "delete")
+        return tuscany::partitioner::del(cadr(params), caddr(params), cdddr(params));
+    return tuscany::mkfailure<tuscany::value>();
+}
+
+}
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