Tweak example to add serialization

dgraph-io · Nov 16, 2017 · ab4d772 · ab4d772
1 parent 59ecdba
commit ab4d772
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Showing 2 changed files with 68 additions and 36 deletions.
diff --git a/samples/DgraphJavaSample/README.md b/samples/DgraphJavaSample/README.md
@@ -36,7 +36,8 @@ For more configuration options, and other details, refer to [docs.dgraph.io]
 ```
 $ ./gradlew run
 
-> Task :run 
+> Task :run
+people found: 1
 Alice
 
 

diff --git a/samples/DgraphJavaSample/src/main/java/App.java b/samples/DgraphJavaSample/src/main/java/App.java
@@ -1,6 +1,9 @@
+import com.google.gson.Gson;
+import com.google.gson.JsonArray;
 import com.google.gson.JsonObject;
 import com.google.gson.JsonParser;
 import com.google.protobuf.ByteString;
+import io.dgraph.DgraphClient.Transaction;
 import io.dgraph.DgraphGrpc;
 import io.dgraph.DgraphGrpc.DgraphBlockingStub;
 import io.dgraph.DgraphProto.Mutation;
@@ -9,43 +12,71 @@
 import io.dgraph.DgraphClient;
 import io.grpc.ManagedChannel;
 import io.grpc.ManagedChannelBuilder;
+import java.util.Collection;
 import java.util.Collections;
+import java.util.List;
 import java.util.Map;
-import java.util.concurrent.TimeUnit;
 
 public class App {
-  private static final String TEST_HOSTNAME = "localhost";
-  private static final int TEST_PORT = 9080;
-
-  public static void main(final String[] args) {
-    ManagedChannel channel = ManagedChannelBuilder.forAddress(TEST_HOSTNAME, TEST_PORT).usePlaintext(true).build();
-    DgraphBlockingStub blockingStub = DgraphGrpc.newBlockingStub(channel);
-    DgraphClient dgraphClient = new DgraphClient(Collections.singletonList(blockingStub));
-
-    // Set schema
-    Operation op = Operation.newBuilder().setSchema("name: string @index(exact) .").build();
-    dgraphClient.alter(op);
-
-    // Add data
-    JsonObject json = new JsonObject();
-    json.addProperty("name", "Alice");
-
-    Mutation mu =
-      Mutation.newBuilder()
-      .setCommitNow(true)
-      .setSetJson(ByteString.copyFromUtf8(json.toString()))
-      .build();
-    dgraphClient.newTransaction().mutate(mu);
-
-    // Query
-    String query = "{\n" + "me(func: eq(name, $a)) {\n" + "    name\n" + "  }\n" + "}";
-    Map<String, String> vars = Collections.singletonMap("$a", "Alice");
-    Response res = dgraphClient.newTransaction().query(query, vars);
-
-    // Verify data as expected
-    JsonParser parser = new JsonParser();
-    json = parser.parse(res.getJson().toStringUtf8()).getAsJsonObject();
-    String name = json.getAsJsonArray("me").get(0).getAsJsonObject().get("name").getAsString();
-    System.out.println(name);
-  }
+    private static final String TEST_HOSTNAME = "localhost";
+    private static final int TEST_PORT = 9080;
+
+    public static void main(final String[] args) {
+        ManagedChannel channel = ManagedChannelBuilder.forAddress(TEST_HOSTNAME, TEST_PORT).usePlaintext(true).build();
+        DgraphBlockingStub blockingStub = DgraphGrpc.newBlockingStub(channel);
+        DgraphClient dgraphClient = new DgraphClient(Collections.singletonList(blockingStub));
+
+        // Initialize
+        dgraphClient.alter(Operation.newBuilder().setDropAll(true).build());
+
+        // Set schema
+        String schema = "name: string @index(exact) .";
+        Operation op = Operation.newBuilder().setSchema(schema).build();
+        dgraphClient.alter(op);
+
+        Gson gson = new Gson(); // For JSON encode/decode
+
+        Transaction txn = dgraphClient.newTransaction();
+        try {
+            // Create data
+            Person p = new Person();
+            p.name = "Alice";
+
+            // Serialize it
+            String json = gson.toJson(p);
+
+            // Run mutation
+            Mutation mu =
+                    Mutation.newBuilder()
+                            .setSetJson(ByteString.copyFromUtf8(json.toString()))
+                            .build();
+            txn.mutate(mu);
+            txn.commit();
+
+        } finally {
+            txn.discard();
+        }
+        // Query
+        String query = "{\n" + "all(func: eq(name, $a)) {\n" + "    name\n" + "  }\n" + "}";
+        Map<String, String> vars = Collections.singletonMap("$a", "Alice");
+        Response res = dgraphClient.newTransaction().query(query, vars);
+
+        // Deserialize
+        People ppl = gson.fromJson(res.getJson().toStringUtf8(), People.class);
+
+        // Print results
+        System.out.printf("people found: %d\n", ppl.all.size());
+        ppl.all.forEach(person -> System.out.println(person.name));
+    }
+
+    static class Person {
+        String name;
+        Person() {}
+    }
+
+    static class People {
+        List<Person> all;
+
+        People() {}
+    }
 }