Create AsyncDatabase.java

janbodnar · web-flow · commit b3ffaff0b3cd · 2019-09-02T09:47:35.000+02:00
diff --git a/async/asyncdb/AsyncDatabase.java b/async/asyncdb/AsyncDatabase.java
@@ -0,0 +1,59 @@
+package com.zetcode;
+
+import com.github.jasync.sql.db.Connection;
+import com.github.jasync.sql.db.ConnectionPoolConfigurationBuilder;
+import com.github.jasync.sql.db.QueryResult;
+import com.github.jasync.sql.db.postgresql.PostgreSQLConnectionBuilder;
+import io.javalin.Javalin;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.TimeUnit;
+
+// example for asynchronous database access with Jasync and Javalin
+
+public class AsyncDatabase {
+
+    private static final Logger logger = LoggerFactory.getLogger(AsyncDatabase.class);
+
+    public static void main(String[] args) {
+
+        var config = new ConnectionPoolConfigurationBuilder();
+        config.setUsername("postgres");
+        config.setPassword("s$cret");
+        config.setDatabase("postgres");
+        config.setMaxActiveConnections(100);
+        config.setMaxIdleTime(TimeUnit.MINUTES.toMillis(15));
+        config.setMaxPendingQueries(10000);
+        config.setConnectionValidationInterval(TimeUnit.SECONDS.toMillis(30));
+
+        Connection connection = PostgreSQLConnectionBuilder.createConnectionPool(config);
+
+        Javalin app = Javalin.create()
+                .events(event -> {
+                    event.serverStarting(() -> {
+                        logger.info("--- SERVER STARTING!");
+                        connection.connect().get();
+                        logger.info("--- connection STARTED!");
+                    });
+                    event.serverStopping(() -> {
+                        logger.info("--- SERVER STOPPING!");
+                        connection.disconnect().get();
+                        logger.info("--- connection STOPPED!");
+                    });
+                })
+                .start(7000);
+
+        app.get("/", (ctx) -> {
+
+            final CompletableFuture<QueryResult> queryResultCompletableFuture =
+                    connection.sendPreparedStatement("select 3+6");
+
+            ctx.result(
+                    queryResultCompletableFuture
+                            .thenApply((t) -> "got result: " + t.getRows().get(0).get(0))
+            );
+        });
+    }
+}
