130 lines
3.8 KiB
C++
130 lines
3.8 KiB
C++
/**
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* Licensed to the Apache Software Foundation (ASF) under one
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* or more contributor license agreements. See the NOTICE file
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* distributed with this work for additional information
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* regarding copyright ownership. The ASF licenses this file
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* to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing,
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* software distributed under the License is distributed on an
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* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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* KIND, either express or implied. See the License for the
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* specific language governing permissions and limitations
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* under the License.
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*/
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#ifndef TABEL_VIEW_HPP_
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#define TABEL_VIEW_HPP_
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#include <pulsar/Result.h>
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#include <pulsar/TableViewConfiguration.h>
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#include <pulsar/defines.h>
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#include <functional>
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#include <unordered_map>
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namespace pulsar {
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class TableViewImpl;
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typedef std::function<void(Result result)> ResultCallback;
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typedef std::function<void(const std::string& key, const std::string& value)> TableViewAction;
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/**
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*
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*/
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class PULSAR_PUBLIC TableView {
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public:
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/**
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* Construct an uninitialized tableView object
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*/
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TableView();
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/**
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* Move the latest value associated with the key.
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*
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* Example:
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*
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* ```c++
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* TableView view;
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* std::string value;
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* while (true) {
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* if (view.retrieveValue("key", value)) {
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* std::cout << "value is updated to: " << value;
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* } else {
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* // sleep for a while or print the message that value is not updated
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* }
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* }
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* ```
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*
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* @param key
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* @param value the value associated with the key
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* @return true if there is an associated value of the key, otherwise false
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*
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* NOTE: Once the value has been retrieved successfully, the associated value
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* will be removed from the table view until next time the value is updated.
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*/
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bool retrieveValue(const std::string& key, std::string& value);
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/**
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* It's similar with retrievedValue except the value is copied into `value`.
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*
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* @param key
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* @param value the value associated with the key
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* @return Whether the key exists in the table view.
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*/
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bool getValue(const std::string& key, std::string& value) const;
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/**
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* Check if the key exists in the table view.
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*
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* @return true if the key exists in the table view
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*/
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bool containsKey(const std::string& key) const;
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/**
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* Move the table view data into the unordered map.
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*/
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std::unordered_map<std::string, std::string> snapshot();
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/**
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* Get the size of the elements.
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*/
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std::size_t size() const;
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/**
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* Performs the given action for each entry in this map until all entries have been processed or the
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* action throws an exception.
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*/
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void forEach(TableViewAction action);
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/**
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* Performs the given action for each entry in this map until all entries have been processed and
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* register the callback, which will be called each time a key-value pair is updated.
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*/
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void forEachAndListen(TableViewAction action);
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/**
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* Asynchronously close the tableview and stop the broker to push more messages
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*/
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void closeAsync(ResultCallback callback);
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/**
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* Close the table view and stop the broker to push more messages
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*/
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Result close();
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private:
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typedef std::shared_ptr<TableViewImpl> TableViewImplPtr;
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TableViewImplPtr impl_;
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explicit TableView(TableViewImplPtr);
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friend class PulsarFriend;
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friend class ClientImpl;
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};
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} // namespace pulsar
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#endif /* TABEL_VIEW_HPP_ */
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