Refactored applications and addressed peer review comments

.github/workflows/test.yml

@@ -47,11 +47,11 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-      - name: Set up JDK 11
+      - name: Set up JDK 17
         uses: actions/setup-java@v4
         with:
           distribution: 'semeru'
-          java-version: 11
+          java-version: 17
       - run: unset _JAVA_OPTIONS
 
       - name: Run tests

finish/inventory/pom.xml

@@ -12,8 +12,8 @@
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
-        <maven.compiler.source>11</maven.compiler.source>
-        <maven.compiler.target>11</maven.compiler.target>
+        <maven.compiler.source>17</maven.compiler.source>
+        <maven.compiler.target>17</maven.compiler.target>
 
         <!-- OpenLiberty runtime -->
         <liberty.var.system.http.port>9080</liberty.var.system.http.port>
@@ -40,19 +40,19 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter</artifactId>
-            <version>5.14.0</version>
+            <version>6.0.0</version>
             <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>org.jboss.resteasy</groupId>
             <artifactId>resteasy-client</artifactId>
-            <version>6.2.14.Final</version>
+            <version>7.0.0.Final</version>
             <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>org.jboss.resteasy</groupId>
             <artifactId>resteasy-json-binding-provider</artifactId>
-            <version>6.2.14.Final</version>
+            <version>7.0.0.Final</version>
             <scope>test</scope>
         </dependency>
         <dependency>

finish/inventory/src/main/java/io/openliberty/guides/inventory/InventoryManager.java

@@ -11,15 +11,19 @@
 // end::copyright[]
 package io.openliberty.guides.inventory;
 
+import java.net.URI;
 import java.util.ArrayList;
 import java.util.Map;
-import java.util.Properties;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 
 import jakarta.enterprise.context.ApplicationScoped;
 import jakarta.inject.Inject;
+import jakarta.json.JsonObject;
 
 import org.eclipse.microprofile.config.inject.ConfigProperty;
+import org.eclipse.microprofile.rest.client.RestClientBuilder;
 
 import io.openliberty.guides.inventory.client.SystemClient;
 import io.openliberty.guides.inventory.model.InventoryList;
@@ -28,63 +32,67 @@
 @ApplicationScoped
 public class InventoryManager {
 
+    // tag::getLogger[]
+    private static final Logger LOGGER =
+        Logger.getLogger(InventoryManager.class.getName());
+    // end::getLogger[]
+
     @Inject
     @ConfigProperty(name = "system.http.port")
     private int SYSTEM_PORT;
 
     private Map<String, SystemData> systems = new ConcurrentHashMap<>();
 
-    public boolean contains(String host) {
-        return systems.containsKey(host);
-    }
-
-    public Properties getProperties(String hostname) {
-        try (SystemClient client = new SystemClient()) {
-            client.init(hostname, SYSTEM_PORT);
-            return client.getProperties();
-        }
-    }
-
-    public String getHealth(String hostname) {
-        try (SystemClient client = new SystemClient()) {
-            client.init(hostname, SYSTEM_PORT);
-            return client.getHealth();
+    public JsonObject getSystemLoad(String hostname) {
+        String uriString = "http://" + hostname + ":" + SYSTEM_PORT + "/system";
+        try (SystemClient client = RestClientBuilder.newBuilder()
+                .baseUri(URI.create(uriString))
+                .build(SystemClient.class)) {
+
+            JsonObject obj = client.getSystemLoad();
+            // tag::log1[]
+            LOGGER.log(Level.INFO,
+                "Retrieved system load from {0}", hostname);
+            // end::log1[]
+            return obj;
+        } catch (RuntimeException e) {
+            // tag::log2[]
+            LOGGER.log(Level.WARNING,
+                "Runtime exception while invoking system service", e);
+            // end::log2[]
+        } catch (Exception e) {
+            // tag::log3[]
+            LOGGER.log(Level.WARNING,
+                "Unexpected exception while processing system service request", e);
+            // end::log3[]
         }
+        return null;
     }
 
     public InventoryList list() {
         return new InventoryList(new ArrayList<>(systems.values()));
     }
 
-    public void add(String host, Properties systemProps, String health) {
-        Properties props = new Properties();
-        props.setProperty("os.name", systemProps.getProperty("os.name"));
-        props.setProperty("user.name", systemProps.getProperty("user.name"));
-
-        systems.put(host, new SystemData(host, props, health));
-    }
-
-    public void update(String host, String health) {
+    public void set(String host, JsonObject systemLoad) {
         SystemData system = systems.get(host);
-        system.setHealth(health);
+        if (system != null) {
+            system.setSystemLoad(systemLoad);
+        } else {
+            systems.put(host, new SystemData(host, systemLoad));
+        }
     }
 
-    public int refreshAllSystemsHealth() {
-        int updated = 0;
+    public void refreshSystemsLoads() {
         for (SystemData system : systems.values()) {
             String hostname = system.getHostname();
-            String newHealth = getHealth(hostname);
-            if (!newHealth.equals(system.getHealth())) {
-                system.setHealth(newHealth);
-                updated++;
-            }
+            JsonObject systemLoad = getSystemLoad(hostname);
+            system.setSystemLoad(systemLoad);
         }
-        return updated;
     }
 
-    int clear() {
-        int propertiesClearedCount = systems.size();
+    public int clear() {
+        int systemsClearedCount = systems.size();
         systems.clear();
-        return propertiesClearedCount;
+        return systemsClearedCount;
     }
 }

finish/inventory/src/main/java/io/openliberty/guides/inventory/InventoryResource.java

@@ -11,13 +11,11 @@
 // end::copyright[]
 package io.openliberty.guides.inventory;
 
-import java.util.Properties;
-
 import jakarta.enterprise.context.RequestScoped;
 import jakarta.inject.Inject;
+import jakarta.json.JsonObject;
 import jakarta.ws.rs.DELETE;
 import jakarta.ws.rs.GET;
-import jakarta.ws.rs.POST;
 import jakarta.ws.rs.Path;
 import jakarta.ws.rs.PathParam;
 import jakarta.ws.rs.Produces;
@@ -38,35 +36,16 @@ public class InventoryResource {
     @GET
     @Path("/{hostname}")
     @Produces(MediaType.APPLICATION_JSON)
-    public Response getPropertiesForHost(@PathParam("hostname") String hostname) {
-        Properties props = null;
-        String health = manager.getHealth(hostname);
-        if (health.equals("ERROR")) {
+    public Response getSystemLoadForHost(@PathParam("hostname") String hostname) {
+        JsonObject systemLoad = manager.getSystemLoad(hostname);
+        if (systemLoad == null) {
             return Response.status(Response.Status.NOT_FOUND)
                         .entity("{ \"error\" : \"Unknown hostname or the system "
                         + "service may not be running on " + hostname + "\" }")
                         .build();
         }
-        props = manager.getProperties(hostname);
-        if (!manager.contains(hostname)) {
-            manager.add(hostname, props, health);
-        } else {
-            manager.update(hostname, health);
-        }
-        return Response.ok(props).build();
-    }
-
-    @POST
-    @Path("/health/refresh")
-    @Produces(MediaType.APPLICATION_JSON)
-    public Response refreshAllSystemsHealth() {
-        int updated = manager.refreshAllSystemsHealth();
-        if (updated == 0) {
-            return Response.ok("{\"ok\": \"No systems needed refresh\"}")
-                           .build();
-        }
-        return Response.ok("{\"ok\": \"Health refresh completed for all systems\", \"updated\": " + updated + "}")
-                       .build();
+        manager.set(hostname, systemLoad);
+        return Response.ok(systemLoad).build();
     }
 
     @GET
@@ -83,7 +62,8 @@ public Response clearContents() {
             return Response.ok("{\"ok\": \"No systems to clear\"}")
                            .build();
         }
-        return Response.ok("{\"ok\": \"Cleared all systems\", \"cleared\": " + cleared + "}")
+        return Response.ok("{\"ok\": \"Cleared all systems\", \"cleared\": "
+                           + cleared + "}")
                        .build();
     }
 }

finish/inventory/src/main/java/io/openliberty/guides/inventory/HealthCheckScheduler.java → finish/inventory/src/main/java/io/openliberty/guides/inventory/SystemLoadRefreshScheduler.java

@@ -18,13 +18,13 @@
 
 @Singleton
 @Startup
-public class HealthCheckScheduler {
+public class SystemLoadRefreshScheduler {
 
     @Inject
     private InventoryManager inventoryManager;
 
-    @Schedule(hour = "*", minute = "*", second = "*/30", persistent = false)
-    public void performHealthChecks() {
-        inventoryManager.refreshAllSystemsHealth();
+    @Schedule(hour = "*", minute = "*", second = "*/15", persistent = false)
+    public void refreshSystemLoads() {
+        inventoryManager.refreshSystemsLoads();
     }
 }

finish/inventory/src/main/java/io/openliberty/guides/inventory/client/SystemClient.java

@@ -11,130 +11,19 @@
 // end::copyright[]
 package io.openliberty.guides.inventory.client;
 
-import java.net.URI;
-import java.util.Properties;
-import java.util.logging.Level;
-import java.util.logging.Logger;
-
-import jakarta.ws.rs.client.Client;
-import jakarta.ws.rs.client.ClientBuilder;
-import jakarta.ws.rs.client.Invocation.Builder;
-import jakarta.ws.rs.core.HttpHeaders;
+import jakarta.json.JsonObject;
+import jakarta.ws.rs.GET;
+import jakarta.ws.rs.Path;
+import jakarta.ws.rs.Produces;
 import jakarta.ws.rs.core.MediaType;
-import jakarta.ws.rs.core.Response;
-import jakarta.ws.rs.core.Response.Status;
-
-public class SystemClient implements AutoCloseable {
-
-    // tag::getLogger[]
-    private static final Logger LOGGER = Logger.getLogger(SystemClient.class.getName());
-    // end::getLogger[]
-
-    private static final String PROTOCOL = "http";
-    private static final String SYSTEM_PROPERTIES = "/system/properties";
-    private static final String SYSTEM_HEALTH = "/health";
-
-    private String hostname;
-    private int port;
-    private Client client;
-
-    public void init(String hostname, int port) {
-        this.hostname = hostname;
-        this.port = port;
-    }
-
-    private String buildUrl(String path) {
-        try {
-            URI uri = new URI(PROTOCOL, null, hostname, port, path, null, null);
-            return uri.toString();
-        } catch (Exception e) {
-            // tag::log1[]
-            LOGGER.log(Level.WARNING,
-                "URISyntaxException while building system service URL", e);
-            // end::log1[]
-            return null;
-        }
-    }
-
-    private Builder buildClientBuilder(String urlString) {
-        try {
-            this.client = ClientBuilder.newClient();
-            Builder builder = client.target(urlString).request();
-            return builder.header(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON);
-        } catch (Exception e) {
-            // tag::log2[]
-            LOGGER.log(Level.WARNING,
-                "Exception while creating REST client builder", e);
-            // end::log2[]
-            return null;
-        }
-    }
-
-    public Properties getProperties() {
-        String url = buildUrl(SYSTEM_PROPERTIES);
-        Builder builder = buildClientBuilder(url);
-        if (builder == null) {
-            return null;
-        }
-
-        try {
-            Response response = builder.get();
-            // tag::log3[]
-            LOGGER.log(Level.INFO,
-                "Received response with status: {0}", response.getStatus());
-            // end::log3[]
-            if (response.getStatus() == Status.OK.getStatusCode()) {
-                return response.readEntity(Properties.class);
-            } else {
-                // tag::log4[]
-                LOGGER.log(Level.WARNING,
-                    "Response Status is not OK: {0}", response.getStatus());
-                // end::log4[]
-            }
-        } catch (RuntimeException e) {
-            // tag::log5[]
-            LOGGER.log(Level.WARNING,
-                "Runtime exception while invoking system service", e);
-            // end::log5[]
-        } catch (Exception e) {
-            // tag::log6[]
-            LOGGER.log(Level.WARNING,
-                "Unexpected exception while processing system service request", e);
-            // end::log6[]
-        }
-        return null;
-    }
 
-    public String getHealth() {
-        String url = buildUrl(SYSTEM_HEALTH);
-        Builder builder = buildClientBuilder(url);
-        if (builder == null) {
-            return "ERROR";
-        }
+import org.eclipse.microprofile.rest.client.inject.RegisterRestClient;
 
-        try {
-            Response response = builder.get();
-            int statusCode = response.getStatus();
-            if (statusCode == Status.OK.getStatusCode()) {
-                return "UP";
-            } else if (statusCode == Status.SERVICE_UNAVAILABLE.getStatusCode()) {
-                return "DOWN";
-            } else {
-                return "ERROR";
-            }
-        } catch (Exception e) {
-            // tag::log7[]
-            LOGGER.log(Level.WARNING,
-                "Unexpected exception while invoking system health endpoint", e);
-            // end::log7[]
-        }
-        return "ERROR";
-    }
+@RegisterRestClient
+@Path("/systemLoad")
+public interface SystemClient extends AutoCloseable {
 
-    @Override
-    public void close() {
-        if (client != null) {
-            client.close();
-        }
-    }
+    @GET
+    @Produces(MediaType.APPLICATION_JSON)
+    JsonObject getSystemLoad() throws RuntimeException, Exception;
 }