#3 - Add JsonWriter.writeRaw() to support x-json-stream content

Additionally, #2 Add JsonWriter.pretty(boolean) to support pretty formatted json

Author: rbygrave

blackbox-test/src/test/java/org/example/customer/CustomerTest.java

@@ -13,9 +13,10 @@ class CustomerTest {
 
   final String jsonStart = "{\"id\":42,\"name\":\"rob\",\"status\":\"ACTIVE\",\"whenCreated\":";
 
+  Jsonb jsonb = Jsonb.newBuilder().build();
+
   @Test
   void toJson_view() {
-    Jsonb jsonb = Jsonb.newBuilder().build();
     JsonView<Customer> customerJsonView = jsonb.type(Customer.class).view("(id, name)");
 
     var customer = new Customer().id(42L).name("rob").status(Customer.Status.ACTIVE).whenCreated(Instant.now());
@@ -31,7 +32,6 @@ void toJson()  {
     customer.contacts().add(new Contact(UUID.randomUUID(), "fo", "nar"));
     customer.contacts().add(new Contact(UUID.randomUUID(), "ba", "zar"));
 
-    Jsonb jsonb = Jsonb.newBuilder().build();
     JsonType<Customer> customerType = jsonb.type(Customer.class);
     String asJson = customerType.toJson(customer);
     assertThat(asJson).startsWith(jsonStart);
@@ -61,7 +61,6 @@ void toJson()  {
 
   @Test
   void fromObject()  {
-    var jsonb = Jsonb.newBuilder().build();
 
     var customerJson = jsonb.type(Customer.class);
 
@@ -99,7 +98,6 @@ void toJson_viaTypeObject()  {
 
     Object customerAsObject = new Customer().id(42L).name("rob").status(Customer.Status.ACTIVE);
 
-    Jsonb jsonb = Jsonb.newBuilder().build();
     String asJson = jsonb.type(Object.class).toJson(customerAsObject);
     assertThat(asJson).isEqualTo("{\"id\":42,\"name\":\"rob\",\"status\":\"ACTIVE\"}");
 
@@ -108,4 +106,78 @@ void toJson_viaTypeObject()  {
     assertThat(from1.name()).isEqualTo("rob");
     assertThat(from1.status()).isEqualTo(Customer.Status.ACTIVE);
   }
+
+  @Test
+  void toJson_pretty() {
+    StringWriter stringWriter = new StringWriter();
+    try (JsonWriter writer = jsonb.writer(stringWriter)) {
+      writer.pretty(true);
+      Customer customer = new Customer().id(42L).name("rob").status(Customer.Status.ACTIVE);
+      jsonb.type(Customer.class).toJson(writer, customer);
+    }
+    assertThat(stringWriter.toString()).isEqualTo("""
+      {
+        "id" : 42,
+        "name" : "rob",
+        "status" : "ACTIVE"
+      }""");
+  }
+
+  @Test
+  void toJsonStream() {
+
+    var customers = List.of(
+      new Customer().id(42L).name("rob").status(Customer.Status.ACTIVE),
+      new Customer().id(43L).name("job").status(Customer.Status.NEW),
+      new Customer().id(44L).name("bob").status(Customer.Status.ACTIVE));
+
+    JsonType<Customer> type = jsonb.type(Customer.class);
+    StringWriter writer = new StringWriter();
+
+    try (JsonWriter jsonWriter = jsonb.writer(writer)) {
+      jsonWriter.pretty(false);
+      for (Customer customer : customers) {
+        type.toJson(jsonWriter, customer);
+        jsonWriter.writeRaw('\n');
+      }
+    }
+    String streamJson = writer.toString();
+    assertThat(streamJson).isEqualTo(
+      "{\"id\":42,\"name\":\"rob\",\"status\":\"ACTIVE\"}\n" +
+      " {\"id\":43,\"name\":\"job\",\"status\":\"NEW\"}\n" +
+      " {\"id\":44,\"name\":\"bob\",\"status\":\"ACTIVE\"}\n");
+  }
+
+  @Test
+  void toJsonStream_viaMethod() {
+    var customers = List.of(
+      new Customer().id(42L).name("rob").status(Customer.Status.ACTIVE),
+      new Customer().id(43L).name("job").status(Customer.Status.NEW),
+      new Customer().id(44L).name("bob").status(Customer.Status.ACTIVE));
+
+    StringWriter writer = new StringWriter();
+    try (JsonWriter jsonWriter = jsonb.writer(writer)) {
+      toStream(customers.iterator(), jsonWriter);
+    }
+
+    String streamJson = writer.toString();
+    assertThat(streamJson).isEqualTo(
+      "{\"id\":42,\"name\":\"rob\",\"status\":\"ACTIVE\"}\n" +
+      " {\"id\":43,\"name\":\"job\",\"status\":\"NEW\"}\n" +
+      " {\"id\":44,\"name\":\"bob\",\"status\":\"ACTIVE\"}\n");
+  }
+
+  <T> void toStream(Iterator<T> iterator, JsonWriter jsonWriter) {
+    if (iterator.hasNext()) {
+      jsonWriter.pretty(false);
+      T first = iterator.next();
+      JsonType<T> type = jsonb.typeOf(first);
+      type.toJson(jsonWriter, first);
+      jsonWriter.writeRaw('\n');
+      while (iterator.hasNext()) {
+        type.toJson(jsonWriter, iterator.next());
+        jsonWriter.writeRaw('\n');
+      }
+    }
+  }
 }

jsonb/src/main/java/io/avaje/jsonb/JsonWriter.java

@@ -47,6 +47,11 @@ public interface JsonWriter extends Closeable, Flushable {
    */
   boolean serializeEmpty();
 
+  /**
+   * Set tp true to output json in pretty format.
+   */
+  void pretty(boolean pretty);
+
   /**
    * Return the current path.
    */
@@ -159,6 +164,12 @@ public interface JsonWriter extends Closeable, Flushable {
    */
   void jsonValue(Object value);
 
+  /**
+   * Write raw content. This is typically used to write new line characters for
+   * {@code x-json-stream} content.
+   */
+  void writeRaw(char ch);
+
   /**
    * Flush the writer.
    */

jsonb/src/main/java/io/avaje/jsonb/Jsonb.java

@@ -4,7 +4,10 @@
 import io.avaje.jsonb.spi.Bootstrap;
 import io.avaje.jsonb.spi.PropertyNames;
 
-import java.io.*;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.Reader;
+import java.io.Writer;
 import java.lang.reflect.Type;
 import java.util.Iterator;
 import java.util.ServiceLoader;
@@ -115,6 +118,17 @@ static Builder newBuilder() {
    */
   <T> JsonType<T> type(Type type);
 
+  /**
+   * Return the JsonType for the given value using the values class.
+   * <p>
+   * This is a helper method that supports returning an inferred generic type.
+   *
+   * @param value The value of the given type
+   * @param <T>   The inferred generic parameter type
+   * @return JsonType for the given value
+   */
+  <T> JsonType<T> typeOf(Object value);
+
   /**
    * Return the JsonAdapter used to read and write json for the given class.
    */

jsonb/src/main/java/io/avaje/jsonb/core/DJsonb.java

@@ -83,6 +83,12 @@ public <T> JsonType<T> type(Type type) {
     return typeWithCache(type);
   }
 
+  @Override
+  public <T> JsonType<T> typeOf(Object first) {
+    requireNonNull(first);
+    return type((Type)first.getClass());
+  }
+
   @SuppressWarnings("unchecked")
   private <T> JsonType<T> typeWithCache(Type type) {
     return (JsonType<T>) typeCache.computeIfAbsent(type, _type -> new DJsonType<>(this, _type, adapter(_type)));

jsonb/src/main/java/io/avaje/jsonb/jackson/JacksonWriter.java

@@ -47,6 +47,15 @@ public void flush() {
     }
   }
 
+  @Override
+  public void pretty(boolean pretty) {
+    if (!pretty) {
+      generator.setPrettyPrinter(null);
+    } else {
+      generator.useDefaultPrettyPrinter();
+    }
+  }
+
   @Override
   public void serializeNulls(boolean serializeNulls) {
     this.serializeNulls = serializeNulls;
@@ -324,6 +333,15 @@ public void value(BigInteger value) {
     }
   }
 
+  @Override
+  public void writeRaw(char ch) {
+    try {
+      generator.writeRaw(ch);
+    } catch (IOException e) {
+      throw new JsonIoException(e);
+    }
+  }
+
   @Override
   public void jsonValue(Object value) {
     if (value instanceof Map<?, ?>) {

jsonb/src/main/java/io/avaje/jsonb/spi/DelegateJsonWriter.java

@@ -36,6 +36,11 @@ public void serializeEmpty(boolean serializeEmpty) {
     delegate.serializeEmpty(serializeEmpty);
   }
 
+  @Override
+  public void pretty(boolean pretty) {
+    delegate.pretty(pretty);
+  }
+
   @Override
   public String path() {
     return delegate.path();
@@ -146,6 +151,11 @@ public void jsonValue(Object value) {
     delegate.jsonValue(value);
   }
 
+  @Override
+  public void writeRaw(char ch) {
+    delegate.writeRaw(ch);
+  }
+
   @Override
   public void close() {
     delegate.close();