JsonArray optimizations

src/main/java/io/vertx/core/json/JsonArray.java

@@ -19,6 +19,7 @@
 import java.util.*;
 import java.util.function.Function;
 import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
 
 import static io.vertx.core.json.impl.JsonUtil.*;
 import static java.time.format.DateTimeFormatter.ISO_INSTANT;
@@ -65,16 +66,27 @@ public JsonArray() {
     list = new ArrayList<>();
   }
 
+  /**
+   * Create an empty instance with initialCapacity
+   */
+  public JsonArray(int initialCapacity) {
+    list = new ArrayList<>(initialCapacity);
+  }
+
   /**
    * Create an instance from a List. The List is not copied.
    *
    * @param list the underlying backing list
    */
-  public JsonArray(List list) {
-    if (list == null) {
+  @SuppressWarnings({"rawtypes", "unchecked"})
+  public JsonArray(Collection list) {
+    if (list instanceof List) {
+      this.list = (List) list;
+    } else if (list == null) {
       throw new NullPointerException();
+    } else {
+      this.list = new ArrayList(list);
     }
-    this.list = list;
   }
 
   /**
@@ -100,12 +112,13 @@ public JsonArray(Buffer buf) {
    */
   public static JsonArray of(Object... values) {
     // implicit nullcheck of values
-    if (values.length == 0) {
+    int len = values.length;
+    if (len == 0) {
       return new JsonArray();
     }
 
-    JsonArray arr = new JsonArray(new ArrayList<>(values.length));
-    for(int i = 0; i< values.length; ++i) {
+    JsonArray arr = new JsonArray(new ArrayList<>(len));
+    for (int i = 0; i < len; ++i) {
       arr.add(values[i]);
     }
 
@@ -616,7 +629,13 @@ public JsonArray copy(Function<Object, ?> cloner) {
    * @return a Stream
    */
   public Stream<Object> stream() {
-    return asStream(iterator());
+    // JsonUtil.asStream(iterator()) is too generic
+    return StreamSupport.stream(spliterator(), false);
+  }
+
+  @Override
+  public Spliterator<Object> spliterator() {
+    return Spliterators.spliterator(iterator(), list.size(), Spliterator.ORDERED);
   }
 
   @Override

src/main/java/io/vertx/core/json/JsonObject.java

@@ -18,6 +18,7 @@
 import java.util.*;
 import java.util.function.Function;
 import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
 
 import static io.vertx.core.json.impl.JsonUtil.*;
 import static java.time.format.DateTimeFormatter.ISO_INSTANT;
@@ -54,11 +55,23 @@ public JsonObject(String json) {
     }
   }
 
+  @SuppressWarnings("unchecked")
+  private static <T> Map<String,T> map(int expectedSize) {
+    return (Map<String,T>) MAP_CREATOR.apply(expectedSize);
+  }
+
   /**
    * Create a new, empty instance
    */
   public JsonObject() {
-    map = new LinkedHashMap<>();
+    map = map(0);// => 3
+  }
+
+  /**
+   * Create a new, empty instance with expected size (initial capacity will be calculated)
+   */
+  public JsonObject(int expectedSize) {
+    map = map(expectedSize);
   }
 
   /**
@@ -105,7 +118,7 @@ public static JsonObject of() {
    * @return a JsonObject containing the specified mapping.
    */
   public static JsonObject of(String k1, Object v1) {
-    JsonObject obj = new JsonObject(new LinkedHashMap<>(1));
+    JsonObject obj = new JsonObject(map(1));
 
     obj.put(k1, v1);
 
@@ -122,7 +135,7 @@ public static JsonObject of(String k1, Object v1) {
    * @return a JsonObject containing the specified mappings.
    */
   public static JsonObject of(String k1, Object v1, String k2, Object v2) {
-    JsonObject obj = new JsonObject(new LinkedHashMap<>(2));
+    JsonObject obj = new JsonObject(map(2));
 
     obj.put(k1, v1);
     obj.put(k2, v2);
@@ -142,7 +155,7 @@ public static JsonObject of(String k1, Object v1, String k2, Object v2) {
    * @return a JsonObject containing the specified mappings.
    */
   public static JsonObject of(String k1, Object v1, String k2, Object v2, String k3, Object v3) {
-    JsonObject obj = new JsonObject(new LinkedHashMap<>(3));
+    JsonObject obj = new JsonObject(map(3));
 
     obj.put(k1, v1);
     obj.put(k2, v2);
@@ -166,7 +179,7 @@ public static JsonObject of(String k1, Object v1, String k2, Object v2, String k
    */
   public static JsonObject of(String k1, Object v1, String k2, Object v2, String k3, Object v3,
                               String k4, Object v4) {
-    JsonObject obj = new JsonObject(new LinkedHashMap<>(4));
+    JsonObject obj = new JsonObject(map(4));
 
     obj.put(k1, v1);
     obj.put(k2, v2);
@@ -193,7 +206,7 @@ public static JsonObject of(String k1, Object v1, String k2, Object v2, String k
    */
   public static JsonObject of(String k1, Object v1, String k2, Object v2, String k3, Object v3,
                               String k4, Object v4, String k5, Object v5) {
-    JsonObject obj = new JsonObject(new LinkedHashMap<>(5));
+    JsonObject obj = new JsonObject(map(5));
 
     obj.put(k1, v1);
     obj.put(k2, v2);
@@ -223,7 +236,7 @@ public static JsonObject of(String k1, Object v1, String k2, Object v2, String k
    */
   public static JsonObject of(String k1, Object v1, String k2, Object v2, String k3, Object v3,
                               String k4, Object v4, String k5, Object v5, String k6, Object v6) {
-    JsonObject obj = new JsonObject(new LinkedHashMap<>(6));
+    JsonObject obj = new JsonObject(map(6));
 
     obj.put(k1, v1);
     obj.put(k2, v2);
@@ -257,7 +270,7 @@ public static JsonObject of(String k1, Object v1, String k2, Object v2, String k
   public static JsonObject of(String k1, Object v1, String k2, Object v2, String k3, Object v3,
                               String k4, Object v4, String k5, Object v5, String k6, Object v6,
                               String k7, Object v7) {
-    JsonObject obj = new JsonObject(new LinkedHashMap<>(7));
+    JsonObject obj = new JsonObject(map(7));
 
     obj.put(k1, v1);
     obj.put(k2, v2);
@@ -294,7 +307,7 @@ public static JsonObject of(String k1, Object v1, String k2, Object v2, String k
   public static JsonObject of(String k1, Object v1, String k2, Object v2, String k3, Object v3,
                               String k4, Object v4, String k5, Object v5, String k6, Object v6,
                               String k7, Object v7, String k8, Object v8) {
-    JsonObject obj = new JsonObject(new LinkedHashMap<>(8));
+    JsonObject obj = new JsonObject(map(8));
 
     obj.put(k1, v1);
     obj.put(k2, v2);
@@ -334,7 +347,7 @@ public static JsonObject of(String k1, Object v1, String k2, Object v2, String k
   public static JsonObject of(String k1, Object v1, String k2, Object v2, String k3, Object v3,
                               String k4, Object v4, String k5, Object v5, String k6, Object v6,
                               String k7, Object v7, String k8, Object v8, String k9, Object v9) {
-    JsonObject obj = new JsonObject(new LinkedHashMap<>(9));
+    JsonObject obj = new JsonObject(map(9));
 
     obj.put(k1, v1);
     obj.put(k2, v2);
@@ -378,7 +391,7 @@ public static JsonObject of(String k1, Object v1, String k2, Object v2, String k
                               String k4, Object v4, String k5, Object v5, String k6, Object v6,
                               String k7, Object v7, String k8, Object v8, String k9, Object v9,
                               String k10, Object v10) {
-    JsonObject obj = new JsonObject(new LinkedHashMap<>(10));
+    JsonObject obj = new JsonObject(map(10));
 
     obj.put(k1, v1);
     obj.put(k2, v2);
@@ -1075,10 +1088,13 @@ public JsonObject copy() {
    */
   public JsonObject copy(Function<Object, ?> cloner) {
     Map<String, Object> copiedMap;
-    if (map instanceof LinkedHashMap) {
-      copiedMap = new LinkedHashMap<>(map.size());
+    int capacity = map.size() * 4 / 3 + 1;
+    if (map instanceof LinkedHashMap){
+      copiedMap = new LinkedHashMap<>(capacity);
+    } else if (map instanceof SortedMap){
+      copiedMap = new TreeMap<>();
     } else {
-      copiedMap = new HashMap<>(map.size());
+      copiedMap = new HashMap<>(capacity);
     }
     for (Map.Entry<String, Object> entry : map.entrySet()) {
       Object val = deepCopy(entry.getValue(), cloner);
@@ -1114,9 +1130,17 @@ public Map<String, Object> getMap() {
    * @return a Stream
    */
   public Stream<Map.Entry<String, Object>> stream() {
-    return asStream(iterator());
+    // JsonUtil.asStream(iterator()) is too generic
+    return StreamSupport.stream(spliterator(), false);
   }
 
+
+  @Override
+  public Spliterator<Map.Entry<String,Object>> spliterator() {
+    return Spliterators.spliterator(iterator(), map.size(), Spliterator.DISTINCT | Spliterator.NONNULL);
+  }
+
+
   /**
    * Get an Iterator of the entries in the JSON object.
    *
@@ -1158,16 +1182,21 @@ public String toString() {
     return encode();
   }
 
+  /**
+   How to Write an Equality Method in Java
+   https://www.artima.com/articles/how-to-write-an-equality-method-in-java
+   */
+  protected boolean canEqual(Object other) {
+    return getClass() == other.getClass();
+  }
+
   @Override
   public boolean equals(Object o) {
-    // null check
-    if (o == null)
-      return false;
     // self check
     if (this == o)
       return true;
-    // type check and cast
-    if (getClass() != o.getClass())
+    // type check, cast, null check
+    if (!(o instanceof JsonObject && ((JsonObject)o).canEqual(this)))
       return false;
 
     JsonObject other = (JsonObject) o;
@@ -1275,7 +1304,9 @@ public Map.Entry<String, Object> next() {
       final Object wrapped = wrapJsonValue(val);
 
       if (val != wrapped) {
-        return new Entry(entry.getKey(), wrapped);
+        // Map.entry disallows null keys and values: we disallow null keys,
+        // (val != wrapped) skips null values (wrapJsonValue doesn't wrap null)
+        return Map.entry(entry.getKey(), wrapped);
       }
 
       return entry;
@@ -1286,29 +1317,4 @@ public void remove() {
       mapIter.remove();
     }
   }
-
-  private static final class Entry implements Map.Entry<String, Object> {
-    final String key;
-    final Object value;
-
-    public Entry(String key, Object value) {
-      this.key = key;
-      this.value = value;
-    }
-
-    @Override
-    public String getKey() {
-      return key;
-    }
-
-    @Override
-    public Object getValue() {
-      return value;
-    }
-
-    @Override
-    public Object setValue(Object value) {
-      throw new UnsupportedOperationException();
-    }
-  }
 }

src/main/java/io/vertx/core/json/impl/JsonUtil.java

@@ -17,10 +17,13 @@
 
 import java.time.Instant;
 import java.util.Base64;
+import java.util.HashMap;
 import java.util.Iterator;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.function.Function;
+import java.util.function.IntFunction;
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
 
@@ -63,10 +66,6 @@ public final class JsonUtil {
    * @return wrapped type or {@code val} if not applicable.
    */
   public static Object wrapJsonValue(Object val) {
-    if (val == null) {
-      return null;
-    }
-
     // perform wrapping
     if (val instanceof Map) {
       val = new JsonObject((Map) val);
@@ -81,14 +80,20 @@ public static Object wrapJsonValue(Object val) {
     } else if (val instanceof Enum) {
       val = ((Enum) val).name();
     }
-
-    return val;
+    return val; // includes null
   }
 
   public static final Function<Object, ?> DEFAULT_CLONER = o -> {
     throw new IllegalStateException("Illegal type in Json: " + o.getClass());
   };
 
+  // todo replace with HashMap? → Less memory usage, but random keys order, but .stream().sorted()?
+  // immutable Map.of javadoc: The iteration order of mappings is unspecified and is subject to change
+  @SuppressWarnings("rawtypes")
+  public static final IntFunction<Map> MAP_CREATOR = size -> new LinkedHashMap(size < 3
+      ? 3
+      : size * 4 / 3 + 1);// ~ size / DEFAULT_LOAD_FACTOR(0.75) + 1
+
   @SuppressWarnings("unchecked")
   public static Object deepCopy(Object val, Function<Object, ?> copier) {
     if (val == null) {
@@ -124,6 +129,11 @@ public static Object deepCopy(Object val, Function<Object, ?> copier) {
     return val;
   }
 
+  /**
+   @deprecated too generic
+   @see Iterable#spliterator()
+   */
+  @Deprecated
   public static <T> Stream<T> asStream(Iterator<T> sourceIterator) {
     Iterable<T> iterable = () -> sourceIterator;
     return StreamSupport.stream(iterable.spliterator(), false);

src/test/java/io/vertx/core/json/JsonObjectTest.java

@@ -12,6 +12,7 @@
 package io.vertx.core.json;
 
 import io.vertx.core.buffer.Buffer;
+import io.vertx.core.json.impl.JsonUtil;
 import io.vertx.core.shareddata.Shareable;
 import io.vertx.test.core.TestUtils;
 import org.junit.Before;
@@ -1973,4 +1974,22 @@ public void testJsonObjectOfArgs() {
   public void testJsonObjectOfEmpty() {
     assertEquals(new JsonObject(), JsonObject.of());
   }
+
+  @Test
+  public void testNull() {
+    assertEquals(JsonObject.of(), JsonObject.of());
+    assertFalse(JsonObject.of().equals(null));
+    assertFalse(JsonObject.of().equals(new JsonObject(){}));
+    assertNull(JsonUtil.wrapJsonValue(null));
+
+    JsonObject jo = JsonObject.of("k", null, "", null);
+
+    AtomicInteger cnt = new AtomicInteger();
+    jo.iterator().forEachRemaining(e -> {
+      assertNotNull(e.getKey());
+      assertNull(e.getValue());// null is ok
+      cnt.incrementAndGet();
+    });
+    assertEquals(2, cnt.get());
+  }
 }