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author | giorgio <giorgio@13f79535-47bb-0310-9956-ffa450edef68> | 2012-09-05 08:31:30 +0000 |
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committer | giorgio <giorgio@13f79535-47bb-0310-9956-ffa450edef68> | 2012-09-05 08:31:30 +0000 |
commit | c9bfccc35345ce58fb5774d4b0b6a9868b262c0a (patch) | |
tree | fe84dd4b90f2acd0b933550b6978094926c1d733 /sca-cpp/branches/lightweight-sca/components/cache/partitioner.cpp | |
parent | 5ddabdaf1ff856aae79dadc045ef2aeff08c7887 (diff) |
git-svn-id: http://svn.us.apache.org/repos/asf/tuscany@1381061 13f79535-47bb-0310-9956-ffa450edef68
Diffstat (limited to 'sca-cpp/branches/lightweight-sca/components/cache/partitioner.cpp')
-rw-r--r-- | sca-cpp/branches/lightweight-sca/components/cache/partitioner.cpp | 143 |
1 files changed, 143 insertions, 0 deletions
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>(); +} + +} |