DOC-4528 async hash examples (#3069)

* DOC-4528 first two examples

* DOC-4528 added final example

* DOC-4528 formatting changes

* DOC-4528 removed unused imports

src/test/java/io/redis/examples/async/HashExample.java

@@ -0,0 +1,166 @@
+// EXAMPLE: hash_tutorial
+package io.redis.examples.async;
+
+import io.lettuce.core.*;
+import io.lettuce.core.api.async.RedisAsyncCommands;
+import io.lettuce.core.api.StatefulRedisConnection;
+
+// REMOVE_START
+import org.junit.jupiter.api.Test;
+// REMOVE_END
+import java.util.*;
+import java.util.concurrent.CompletableFuture;
+// REMOVE_START
+import static org.assertj.core.api.Assertions.assertThat;
+// REMOVE_END
+
+public class HashExample {
+
+    @Test
+    public void run() {
+        RedisClient redisClient = RedisClient.create("redis://localhost:6379");
+
+        try (StatefulRedisConnection<String, String> connection = redisClient.connect()) {
+            RedisAsyncCommands<String, String> asyncCommands = connection.async();
+            // REMOVE_START
+            CompletableFuture<Long> delResult = asyncCommands.del("bike:1", "bike:1:stats").toCompletableFuture();
+
+            // REMOVE_END
+
+            // STEP_START set_get_all
+            Map<String, String> bike1 = new HashMap<>();
+            bike1.put("model", "Deimos");
+            bike1.put("brand", "Ergonom");
+            bike1.put("type", "Enduro bikes");
+            bike1.put("price", "4972");
+
+            CompletableFuture<Void> setGetAll = asyncCommands.hset("bike:1", bike1).thenCompose(res1 -> {
+                System.out.println(res1); // >>> 4
+                // REMOVE_START
+                assertThat(res1).isEqualTo(4);
+                // REMOVE_END
+                return asyncCommands.hget("bike:1", "model");
+            }).thenCompose(res2 -> {
+                System.out.println(res2); // >>> Deimos
+                // REMOVE_START
+                assertThat(res2).isEqualTo("Deimos");
+                // REMOVE_END
+                return asyncCommands.hget("bike:1", "price");
+            }).thenCompose(res3 -> {
+                System.out.println(res3); // >>> 4972
+                // REMOVE_START
+                assertThat(res3).isEqualTo("4972");
+                // REMOVE_END
+                return asyncCommands.hgetall("bike:1");
+            })
+                    // REMOVE_START
+                    .thenApply(res -> {
+                        assertThat(res.get("type")).isEqualTo("Enduro bikes");
+                        assertThat(res.get("brand")).isEqualTo("Ergonom");
+                        assertThat(res.get("price")).isEqualTo("4972");
+                        assertThat(res.get("model")).isEqualTo("Deimos");
+
+                        return res;
+                    })
+                    // REMOVE_END
+                    .thenAccept(System.out::println)
+                    // >>> {type=Enduro bikes, brand=Ergonom, price=4972, model=Deimos}
+                    .toCompletableFuture();
+            // STEP_END
+
+            // STEP_START hmget
+            CompletableFuture<Void> hmGet = setGetAll.thenCompose(res4 -> {
+                return asyncCommands.hmget("bike:1", "model", "price");
+            })
+                    // REMOVE_START
+                    .thenApply(res -> {
+                        assertThat(res.toString()).isEqualTo("[KeyValue[model, Deimos], KeyValue[price, 4972]]");
+                        return res;
+                    })
+                    // REMOVE_END
+                    .thenAccept(System.out::println)
+                    // [KeyValue[model, Deimos], KeyValue[price, 4972]]
+                    .toCompletableFuture();
+            // STEP_END
+
+            // STEP_START hincrby
+            CompletableFuture<Void> hIncrBy = hmGet.thenCompose(r -> {
+                return asyncCommands.hincrby("bike:1", "price", 100);
+            }).thenCompose(res6 -> {
+                System.out.println(res6); // >>> 5072
+                // REMOVE_START
+                assertThat(res6).isEqualTo(5072L);
+                // REMOVE_END
+                return asyncCommands.hincrby("bike:1", "price", -100);
+            })
+                    // REMOVE_START
+                    .thenApply(res -> {
+                        assertThat(res).isEqualTo(4972L);
+                        return res;
+                    })
+                    // REMOVE_END
+                    .thenAccept(System.out::println)
+                    // >>> 4972
+                    .toCompletableFuture();
+            // STEP_END
+
+            // STEP_START incrby_get_mget
+            CompletableFuture<Void> incrByGetMget = asyncCommands.hincrby("bike:1:stats", "rides", 1).thenCompose(res7 -> {
+                System.out.println(res7); // >>> 1
+                // REMOVE_START
+                assertThat(res7).isEqualTo(1L);
+                // REMOVE_END
+                return asyncCommands.hincrby("bike:1:stats", "rides", 1);
+            }).thenCompose(res8 -> {
+                System.out.println(res8); // >>> 2
+                // REMOVE_START
+                assertThat(res8).isEqualTo(2L);
+                // REMOVE_END
+                return asyncCommands.hincrby("bike:1:stats", "rides", 1);
+            }).thenCompose(res9 -> {
+                System.out.println(res9); // >>> 3
+                // REMOVE_START
+                assertThat(res9).isEqualTo(3L);
+                // REMOVE_END
+                return asyncCommands.hincrby("bike:1:stats", "crashes", 1);
+            }).thenCompose(res10 -> {
+                System.out.println(res10); // >>> 1
+                // REMOVE_START
+                assertThat(res10).isEqualTo(1L);
+                // REMOVE_END
+                return asyncCommands.hincrby("bike:1:stats", "owners", 1);
+            }).thenCompose(res11 -> {
+                System.out.println(res11); // >>> 1
+                // REMOVE_START
+                assertThat(res11).isEqualTo(1L);
+                // REMOVE_END
+                return asyncCommands.hget("bike:1:stats", "rides");
+            }).thenCompose(res12 -> {
+                System.out.println(res12); // >>> 3
+                // REMOVE_START
+                assertThat(res12).isEqualTo("3");
+                // REMOVE_END
+                return asyncCommands.hmget("bike:1:stats", "crashes", "owners");
+            })
+                    // REMOVE_START
+                    .thenApply(res -> {
+                        assertThat(res.toString()).isEqualTo("[KeyValue[crashes, 1], KeyValue[owners, 1]]");
+                        return res;
+                    })
+                    // REMOVE_END
+                    .thenAccept(System.out::println)
+                    // >>> [KeyValue[crashes, 1], KeyValue[owners, 1]]
+                    .toCompletableFuture();
+            // STEP_END
+
+            CompletableFuture.allOf(
+                    // REMOVE_START
+                    delResult,
+                    // REMOVE_END,
+                    hIncrBy, incrByGetMget).join();
+        } finally {
+            redisClient.shutdown();
+        }
+    }
+
+}