| /* |
| * 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.ignite.snippets; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| import org.apache.ignite.Ignite; |
| import org.apache.ignite.IgniteCache; |
| import org.apache.ignite.IgniteDataStreamer; |
| import org.apache.ignite.Ignition; |
| import org.apache.ignite.configuration.CacheConfiguration; |
| import org.apache.ignite.configuration.IgniteConfiguration; |
| import org.apache.ignite.stream.StreamReceiver; |
| import org.apache.ignite.stream.StreamTransformer; |
| import org.apache.ignite.stream.StreamVisitor; |
| import org.junit.jupiter.api.Test; |
| |
| public class DataStreaming { |
| |
| @Test |
| void dataStreamerExample() { |
| try (Ignite ignite = Ignition.start()) { |
| IgniteCache<Integer, String> cache = ignite.getOrCreateCache("myCache"); |
| //tag::dataStreamer1[] |
| // Get the data streamer reference and stream data. |
| try (IgniteDataStreamer<Integer, String> stmr = ignite.dataStreamer("myCache")) { |
| // Stream entries. |
| for (int i = 0; i < 100000; i++) |
| stmr.addData(i, Integer.toString(i)); |
| //end::dataStreamer1[] |
| //tag::dataStreamer2[] |
| stmr.allowOverwrite(true); |
| //end::dataStreamer2[] |
| //tag::dataStreamer1[] |
| } |
| System.out.println("dataStreamerExample output:" + cache.get(99999)); |
| //end::dataStreamer1[] |
| } |
| } |
| |
| @Test |
| void streamTransformerExample() { |
| try (Ignite ignite = Ignition.start()) { |
| //tag::streamTransformer[] |
| String[] text = { "hello", "world", "hello", "Ignite" }; |
| CacheConfiguration<String, Long> cfg = new CacheConfiguration<>("wordCountCache"); |
| |
| IgniteCache<String, Long> stmCache = ignite.getOrCreateCache(cfg); |
| |
| try (IgniteDataStreamer<String, Long> stmr = ignite.dataStreamer(stmCache.getName())) { |
| // Allow data updates. |
| stmr.allowOverwrite(true); |
| |
| // Configure data transformation to count instances of the same word. |
| stmr.receiver(StreamTransformer.from((e, arg) -> { |
| // Get current count. |
| Long val = e.getValue(); |
| |
| // Increment count by 1. |
| e.setValue(val == null ? 1L : val + 1); |
| |
| return null; |
| })); |
| |
| // Stream words into the streamer cache. |
| for (String word : text) |
| stmr.addData(word, 1L); |
| |
| } |
| //end::streamTransformer[] |
| System.out.println("StreamTransformer example output:" + stmCache.get("hello")); |
| } |
| } |
| |
| @Test |
| void streamReceiverExample() { |
| try (Ignite ignite = Ignition.start()) { |
| ignite.getOrCreateCache("myCache"); |
| //tag::streamReceiver[] |
| try (IgniteDataStreamer<Integer, String> stmr = ignite.dataStreamer("myCache")) { |
| |
| stmr.allowOverwrite(true); |
| |
| stmr.receiver((StreamReceiver<Integer, String>) (cache, entries) -> entries.forEach(entry -> { |
| |
| // do something with the entry |
| |
| cache.put(entry.getKey(), entry.getValue()); |
| })); |
| } |
| //end::streamReceiver[] |
| } |
| } |
| |
| @Test |
| void poolSize() { |
| //tag::pool-size[] |
| IgniteConfiguration cfg = new IgniteConfiguration(); |
| cfg.setDataStreamerThreadPoolSize(10); |
| |
| Ignite ignite = Ignition.start(cfg); |
| //end::pool-size[] |
| ignite.close(); |
| } |
| |
| // tag::stream-visitor[] |
| static class Instrument { |
| final String symbol; |
| Double latest; |
| Double high; |
| Double low; |
| |
| public Instrument(String symbol) { |
| this.symbol = symbol; |
| } |
| |
| } |
| |
| static Map<String, Double> getMarketData() { |
| //populate market data somehow |
| return new HashMap<>(); |
| } |
| |
| @Test |
| void streamVisitorExample() { |
| try (Ignite ignite = Ignition.start()) { |
| CacheConfiguration<String, Double> mrktDataCfg = new CacheConfiguration<>("marketData"); |
| CacheConfiguration<String, Instrument> instCfg = new CacheConfiguration<>("instruments"); |
| |
| // Cache for market data ticks streamed into the system. |
| IgniteCache<String, Double> mrktData = ignite.getOrCreateCache(mrktDataCfg); |
| |
| // Cache for financial instruments. |
| IgniteCache<String, Instrument> instCache = ignite.getOrCreateCache(instCfg); |
| |
| try (IgniteDataStreamer<String, Double> mktStmr = ignite.dataStreamer("marketData")) { |
| // Note that we do not populate the 'marketData' cache (it remains empty). |
| // Instead we update the 'instruments' cache based on the latest market price. |
| mktStmr.receiver(StreamVisitor.from((cache, e) -> { |
| String symbol = e.getKey(); |
| Double tick = e.getValue(); |
| |
| Instrument inst = instCache.get(symbol); |
| |
| if (inst == null) |
| inst = new Instrument(symbol); |
| |
| // Update instrument price based on the latest market tick. |
| inst.high = Math.max(inst.high, tick); |
| inst.low = Math.min(inst.low, tick); |
| inst.latest = tick; |
| |
| // Update the instrument cache. |
| instCache.put(symbol, inst); |
| })); |
| |
| // Stream market data into the cluster. |
| Map<String, Double> marketData = getMarketData(); |
| for (Map.Entry<String, Double> tick : marketData.entrySet()) |
| mktStmr.addData(tick); |
| } |
| } |
| } |
| // end::stream-visitor[] |
| } |