9237

netflix-modules/hollow/pom.xml

@@ -0,0 +1,123 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
+         https://maven.apache.org/xsd/maven-4.0.0.xsd">
+
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>hollow</artifactId>
+    <name>hollow</name>
+    <description>Module for Netflix Hollow</description>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>netflix-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <properties>
+        <maven.compiler.source>21</maven.compiler.source>
+        <maven.compiler.target>21</maven.compiler.target>
+        <maven.compiler.release>21</maven.compiler.release>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <hollow.version>7.14.23</hollow.version>
+        <jupiter.version>5.9.3</jupiter.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.netflix.hollow</groupId>
+            <artifactId>hollow</artifactId>
+            <version>${hollow.version}</version>
+        </dependency>        
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>${jupiter.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <!-- Step 1: Compile producer code in generate-sources phase -->
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.11.0</version>
+                <executions>
+                    <execution>
+                        <id>compile-producer-for-api-generation</id>
+                        <phase>generate-sources</phase>
+                        <goals>
+                            <goal>compile</goal>
+                        </goals>
+                        <configuration>
+                            <includes>
+                                <include>com/baeldung/hollow/model/**/*.java</include>
+                                <include>com/baeldung/hollow/producer/**/*.java</include>
+                                <include>com/baeldung/hollow/service/**/*.java</include>
+                            </includes>
+                            <outputDirectory>${project.build.directory}/classes</outputDirectory>
+                        </configuration>
+                    </execution>
+                    <execution>
+                        <id>compile-all</id>
+                        <phase>compile</phase>
+                        <goals>
+                            <goal>compile</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+
+            <!-- Step 2: Run API generator in process-sources phase (after generate-sources compilation) -->
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>exec-maven-plugin</artifactId>
+                <version>3.0.0</version>
+                <executions>
+                    <execution>
+                        <?m2e execute onConfiguration,onIncremental?>
+                        <id>generate-consumer-api</id>
+                        <phase>process-sources</phase>
+                        <goals>
+                            <goal>java</goal>
+                        </goals>
+                        <configuration>
+                            <mainClass>com.baeldung.hollow.producer.ConsumerApiGenerator</mainClass>
+                            <arguments>
+                                <argument>${project.build.directory}/generated-sources</argument>
+                            </arguments>
+                            <includeProjectDependencies>true</includeProjectDependencies>
+                            <classpathScope>compile</classpathScope>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+
+            <!-- Step 3: Add generated-sources folder as source (in process-sources phase) -->
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>build-helper-maven-plugin</artifactId>
+                <version>3.3.0</version>
+                <executions>
+                    <execution>
+                        <id>add-generated-sources</id>
+                        <phase>process-sources</phase>
+                        <goals>
+                            <goal>add-source</goal>
+                        </goals>
+                        <configuration>
+                            <sources>
+                                <source>${project.build.directory}/generated-sources</source>
+                            </sources>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>

netflix-modules/hollow/src/main/java/com/baeldung/hollow/consumer/MonitoringEventConsumer.java

@@ -0,0 +1,76 @@
+package com.baeldung.hollow.consumer;
+
+import com.baeldung.hollow.consumer.api.MonitoringEvent;
+import com.baeldung.hollow.consumer.api.MonitoringEventAPI;
+import com.netflix.hollow.api.consumer.HollowConsumer;
+import com.netflix.hollow.api.consumer.fs.HollowFilesystemAnnouncementWatcher;
+import com.netflix.hollow.api.consumer.fs.HollowFilesystemBlobRetriever;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Collection;
+
+public class MonitoringEventConsumer {
+    private final static Logger logger = LoggerFactory.getLogger(MonitoringEventConsumer.class);
+
+    static HollowConsumer consumer;
+    static HollowFilesystemAnnouncementWatcher announcementWatcher;
+    static HollowFilesystemBlobRetriever blobRetriever;
+    static MonitoringEventAPI monitoringEventAPI;
+
+    final static long POLL_INTERVAL_MILLISECONDS = 30000;
+
+    public static void main(String[] args) {
+        initialize(getSnapshotFilePath());
+        while (true) {
+            Collection<MonitoringEvent> events = monitoringEventAPI.getAllMonitoringEvent();
+            processEvents(events);
+            sleep(POLL_INTERVAL_MILLISECONDS);
+        }
+    }
+
+    private static void processEvents(Collection<MonitoringEvent> events) {
+        logger.info("Processing {} events", events.size());
+        events.forEach(evt -> {
+            logger.info("Event ID: {}, Name: {}, Type: {}, Status: {}, Device ID: {}, Creation Date: {}",
+                    evt.getEventId(),
+                    evt.getEventName().getValue(),
+                    evt.getEventType().getValue(),
+                    evt.getStatus().getValue(),
+                    evt.getDeviceId().getValue(),
+                    evt.getCreationDate().getValue());
+        });
+    }
+
+    private static void initialize(final Path snapshotPath) {
+        announcementWatcher = new HollowFilesystemAnnouncementWatcher(snapshotPath);
+        blobRetriever = new HollowFilesystemBlobRetriever(snapshotPath);
+        logger.info("snapshot data file location: {}", snapshotPath.toString());
+        consumer = new HollowConsumer.Builder<>()
+                .withAnnouncementWatcher(announcementWatcher)
+                .withBlobRetriever(blobRetriever)
+                .withGeneratedAPIClass(MonitoringEventAPI.class)
+                .build();
+        consumer.triggerRefresh();
+        monitoringEventAPI = consumer.getAPI(MonitoringEventAPI.class);
+    }
+
+    private static void sleep(long milliseconds) {
+        try {
+            Thread.sleep(milliseconds);
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+        }
+    }
+
+    private static Path getSnapshotFilePath() {
+        String moduleDir = System.getProperty("user.dir");
+        String snapshotPath = moduleDir + "/.hollow/snapshots";
+        logger.info("snapshot data directory: {}", snapshotPath);
+
+        Path path = Paths.get(snapshotPath);
+        return path;
+    }
+}

netflix-modules/hollow/src/main/java/com/baeldung/hollow/model/MonitoringEvent.java

@@ -0,0 +1,61 @@
+package com.baeldung.hollow.model;
+
+import com.netflix.hollow.core.write.objectmapper.HollowPrimaryKey;
+
+@HollowPrimaryKey(fields = "eventId")
+public class MonitoringEvent {
+    private int eventId;
+    private String eventName;
+    private String creationDate;
+    private String eventType;
+    private String status;
+    private String deviceId;
+
+    public int getEventId() {
+        return eventId;
+    }
+
+    public void setEventId(int eventId) {
+        this.eventId = eventId;
+    }
+
+    public String getEventName() {
+        return eventName;
+    }
+
+    public void setEventName(String eventName) {
+        this.eventName = eventName;
+    }
+
+    public String getCreationDate() {
+        return creationDate;
+    }
+
+    public void setCreationDate(String creationDate) {
+        this.creationDate = creationDate;
+    }
+
+    public String getEventType() {
+        return eventType;
+    }
+
+    public void setEventType(String eventType) {
+        this.eventType = eventType;
+    }
+
+    public String getStatus() {
+        return status;
+    }
+
+    public void setStatus(String status) {
+        this.status = status;
+    }
+
+    public String getDeviceId() {
+        return deviceId;
+    }
+
+    public void setDeviceId(String deviceId) {
+        this.deviceId = deviceId;
+    }
+}

netflix-modules/hollow/src/main/java/com/baeldung/hollow/producer/ConsumerApiGenerator.java

@@ -0,0 +1,56 @@
+package com.baeldung.hollow.producer;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.baeldung.hollow.model.MonitoringEvent;
+import com.netflix.hollow.api.codegen.HollowAPIGenerator;
+import com.netflix.hollow.core.write.HollowWriteStateEngine;
+import com.netflix.hollow.core.write.objectmapper.HollowObjectMapper;
+
+public class ConsumerApiGenerator {
+    private static final Logger logger = LoggerFactory.getLogger(ConsumerApiGenerator.class);
+
+    public static void main(String[] args) {
+        String sourceDir = args[0];
+        Path outputPath = getGeneratedSourceDirectory(sourceDir);
+
+        HollowWriteStateEngine writeEngine = new HollowWriteStateEngine();
+        HollowObjectMapper mapper = new HollowObjectMapper(writeEngine);
+
+        mapper.initializeTypeState(MonitoringEvent.class);
+
+        logger.info("Starting HollowAPIGenerator with destination: {}", outputPath);
+
+        HollowAPIGenerator generator = new HollowAPIGenerator.Builder()
+                .withDestination(outputPath)
+                .withAPIClassname("MonitoringEventAPI")
+                .withPackageName("com.baeldung.hollow.consumer.api")
+                .withDataModel(writeEngine)
+                .build();
+        try {
+            generator.generateSourceFiles();
+        } catch (IOException e) {
+            logger.error("Error generating consumer API source files", e);
+            throw new RuntimeException(e);
+        }
+    }
+
+    private static Path getGeneratedSourceDirectory(String sourceDir) {
+        Path generatedSourceDir = Paths.get(sourceDir);
+        try {
+            Files.createDirectories(generatedSourceDir);
+        } catch (IOException e) {
+            logger.error("Unable to create output directory {}", generatedSourceDir, e);
+            throw new RuntimeException(e);
+        }
+
+        return generatedSourceDir;
+    }
+
+}