#23 - Stream support, processing as Stream<MyBean> etc

Author: rbygrave

blackbox-test/src/main/java/org/example/customer/stream/MyBasic.java

@@ -0,0 +1,7 @@
+package org.example.customer.stream;
+
+import io.avaje.jsonb.Json;
+
+@Json
+public record MyBasic(int id, String name) {
+}

blackbox-test/src/main/java/org/example/customer/stream/MyNested.java

@@ -0,0 +1,9 @@
+package org.example.customer.stream;
+
+import io.avaje.jsonb.Json;
+
+import java.util.List;
+
+@Json
+public record MyNested(int nest, String desc, List<MyBasic> innerStream) {
+}

blackbox-test/src/test/java/org/example/customer/stream/StreamBasicTest.java

@@ -0,0 +1,85 @@
+package org.example.customer.stream;
+
+import io.avaje.jsonb.JsonReader;
+import io.avaje.jsonb.JsonType;
+import io.avaje.jsonb.Jsonb;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+import java.util.stream.Stream;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class StreamBasicTest {
+
+  Jsonb jsonb = Jsonb.newBuilder().build();
+  JsonType<MyBasic> type = jsonb.type(MyBasic.class);
+  List<MyBasic> basics = List.of(new MyBasic(1, "a"), new MyBasic(2, "b"), new MyBasic(3, "c"));
+
+  @Test
+  void stream_toJson() {
+    String asJson = type.stream().toJson(basics.stream());
+    assertThat(asJson).isEqualTo("[{\"id\":1,\"name\":\"a\"},{\"id\":2,\"name\":\"b\"},{\"id\":3,\"name\":\"c\"}]");
+  }
+
+  @Test
+  void stream_traditionalArray() {
+    String arrayJson = jsonb.toJson(basics);
+    StringBuilder sb = new StringBuilder();
+
+    try (JsonReader reader = jsonb.reader(arrayJson)) {
+      try (Stream<MyBasic> asStream = type.stream(reader)) {
+        asStream.forEach(sb::append);
+      }
+    }
+
+    assertThat(sb.toString()).isEqualTo("MyBasic[id=1, name=a]MyBasic[id=2, name=b]MyBasic[id=3, name=c]");
+
+    // same test but using - JsonType<Stream<T>>
+    JsonType<Stream<MyBasic>> streamJsonType = type.stream();
+
+    sb = new StringBuilder();
+    streamJsonType
+      .fromJson(arrayJson)
+      .forEach(sb::append);
+
+    assertThat(sb.toString()).isEqualTo("MyBasic[id=1, name=a]MyBasic[id=2, name=b]MyBasic[id=3, name=c]");
+  }
+
+  @Test
+  void stream_newLineDelimited() {
+    String arrayJson = jsonb.toJson(basics);
+    String newLineDelimitedJson = arrayJson.replaceAll("[\\[|\\]]", "").replace("},{", "}\n{");
+
+    StringBuilder sb = new StringBuilder();
+    try (JsonReader reader = jsonb.reader(newLineDelimitedJson)) {
+      Stream<MyBasic> asStream = type.stream(reader);
+      asStream.forEach(sb::append);
+    }
+
+    assertThat(sb.toString()).isEqualTo("MyBasic[id=1, name=a]MyBasic[id=2, name=b]MyBasic[id=3, name=c]");
+
+    // same test but using - JsonType<Stream<T>>
+    JsonType<Stream<MyBasic>> streamJsonType = type.stream();
+
+    sb = new StringBuilder();
+    try (Stream<MyBasic> myBasicStream = streamJsonType.fromJson(newLineDelimitedJson)) {
+      myBasicStream.forEach(sb::append);
+      assertThat(sb.toString()).isEqualTo("MyBasic[id=1, name=a]MyBasic[id=2, name=b]MyBasic[id=3, name=c]");
+    }
+  }
+
+  @Test
+  void stream_spaceDelimited() {
+    String arrayJson = "\n" + jsonb.toJson(basics) + "\n";
+    String spaceDelimitedJson = arrayJson.replaceAll("[\\[|\\]]", "").replace("},{", "} {");
+
+    StringBuilder sb = new StringBuilder();
+    try (JsonReader reader = jsonb.reader(spaceDelimitedJson)) {
+      type.stream(reader).forEach(sb::append);
+    }
+
+    assertThat(sb.toString()).isEqualTo("MyBasic[id=1, name=a]MyBasic[id=2, name=b]MyBasic[id=3, name=c]");
+  }
+
+}

blackbox-test/src/test/java/org/example/customer/stream/StreamNestedTest.java

@@ -0,0 +1,38 @@
+package org.example.customer.stream;
+
+import io.avaje.jsonb.JsonReader;
+import io.avaje.jsonb.JsonType;
+import io.avaje.jsonb.Jsonb;
+import org.junit.jupiter.api.Test;
+
+import java.util.stream.Stream;
+
+class StreamNestedTest {
+
+  @Test
+  void nested() {
+
+    String jsonContent = """
+      [
+      {"nest":1, "desc":"d1", "innerStream": [{"id":1,"name":"a"},{"id":2,"name":"b"}] },
+      {"nest":2, "desc":"d2", "innerStream": [{"id":3,"name":"c"}] },
+      {"nest":3, "desc":"d3", "innerStream": [{"id":4,"name":"d"},{"id":5,"name":"e"}] }
+      ]
+      """;
+
+    Jsonb jsonb = Jsonb.newBuilder().build();
+    JsonType<Stream<MyNested>> stream = jsonb.type(MyNested.class).stream();
+
+    try (JsonReader reader = jsonb.reader(jsonContent)) {
+
+      //reader.
+
+      Stream<MyNested> myNestedStream = stream.fromJson(reader);
+      myNestedStream.forEach( myNested -> {
+        int nest = myNested.nest();
+        System.out.println(nest + " " + myNested);
+      });
+    }
+
+  }
+}

jsonb-generator/src/main/java/io/avaje/jsonb/generator/GenericType.java

@@ -176,6 +176,8 @@ private String asTypeContainer() {
         return "Types.listOf(" + Util.shortName(param.topType()) + ".class)";
       case "java.util.Set":
         return "Types.setOf(" + Util.shortName(param.topType()) + ".class)";
+      case "java.util.stream.Stream":
+        return "Types.streamOf(" + Util.shortName(param.topType()) + ".class)";
     }
     return "FIXME: Unhandled Container Type " + containerType;
   }

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

@@ -0,0 +1,21 @@
+package io.avaje.jsonb;
+
+import java.io.IOException;
+
+/**
+ * Thrown when we hit EOF unexpectedly.
+ */
+public class JsonEofException extends JsonIoException {
+
+  public JsonEofException(IOException cause) {
+    super(cause);
+  }
+
+  public JsonEofException(String message, IOException cause) {
+    super(message, cause);
+  }
+
+  public JsonEofException(String message) {
+    super(message);
+  }
+}

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

@@ -33,6 +33,20 @@ public interface JsonReader extends Closeable {
    */
   void names(PropertyNames names);
 
+  /**
+   * Read the beginning of an ARRAY or x-json-stream.
+   */
+  default void beginStream() {
+    beginArray();
+  }
+
+  /**
+   * Read the end of an ARRAY or x-json-stream.
+   */
+  default void endStream() {
+    endArray();
+  }
+
   /**
    * Read array begin.
    */

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

@@ -5,6 +5,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.stream.Stream;
 
 /**
  * Provides API to serialise a type to and from JSON.
@@ -67,6 +68,25 @@ public interface JsonType<T> extends JsonView<T> {
    */
   JsonType<List<T>> list();
 
+  /**
+   * Return the stream type for this JsonType.
+   * <p>
+   * When using this Stream type use a try-with-resources block with the Stream
+   * to ensure that any underlying resources are closed.
+   *
+   * <pre>{@code
+   *
+   *  JsonType<Stream<MyBean>> type =  jsonb.type(MyBean.class).stream();
+   *
+   *  try (Stream<MyBean> asStream = type.fromJson(content)) {
+   *    // use the stream
+   *    ...
+   *  }
+   *
+   * }</pre>
+   */
+  JsonType<Stream<T>> stream();
+
   /**
    * Return the set type for this JsonType.
    */
@@ -110,4 +130,25 @@ public interface JsonType<T> extends JsonView<T> {
    * @return The value converted from 'object form'.
    */
   T fromObject(Object value);
+
+  /**
+   * Return as a Stream that will read the content as the stream is processed.
+   * <p>
+   * Use a try-with-resources block with the JsonReader to ensure the underlying
+   * resources are closed.
+   *
+   * <pre>{@code
+   *
+   *  JsonType<MyBean> type =  jsonb.type(MyBean.class);
+   *
+   *  try (JsonReader reader = jsonb.reader(content)) {
+
+   *    Stream<MyBean> asStream = type.stream(reader);
+   *    ...
+   *  }
+   *
+   * }</pre>
+   */
+  Stream<T> stream(JsonReader reader);
+
 }

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

@@ -22,6 +22,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.stream.Stream;
 
 /**
  * Factory methods for types.
@@ -53,6 +54,13 @@ public static Type setOf(Type elementType) {
     return newParameterizedType(Set.class, elementType);
   }
 
+  /**
+   * Returns a Type that is a Stream of the given element type.
+   */
+  public static Type streamOf(Type elementType) {
+    return newParameterizedType(Stream.class, elementType);
+  }
+
   /**
    * Return the Type for a Map with String keys and the given value element type.
    *

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

@@ -0,0 +1,17 @@
+package io.avaje.jsonb.core;
+
+import io.avaje.jsonb.JsonReader;
+
+/**
+ * Adapter that supports closing the JsonReader when returned object (aka Stream) is closed.
+ */
+interface DJsonClosable<T> {
+
+  /**
+   * Read from the reader additionally closing the reader when done.
+   * <p>
+   * Used when returning a Stream that should close the JsonReader when the
+   * Stream is closed.
+   */
+  T fromJsonWithClose(JsonReader reader);
+}