Support Element.setProperty for lists and maps

flow-server/src/main/java/com/vaadin/flow/dom/Element.java

@@ -17,6 +17,7 @@
 
 import java.io.Serializable;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Optional;
@@ -67,6 +68,8 @@ public class Element extends Node<Element> {
 
     static final String ATTRIBUTE_NAME_CANNOT_BE_NULL = "The attribute name cannot be null";
 
+    private static final String USE_SET_PROPERTY_WITH_JSON_NULL = "setProperty(name, Json.createNull()) must be used to set a property to null";
+
     // Can't set $name as a property, use $replacement instead.
     private static final Map<String, String> illegalPropertyReplacements = new HashMap<>();
 
@@ -658,8 +661,7 @@ public Element setProperty(String name, double value) {
     // Distinct name so setProperty("foo", null) is not ambiguous
     public Element setPropertyJson(String name, JsonValue value) {
         if (value == null) {
-            throw new IllegalArgumentException(
-                    "Json.createNull() must be used instead of null for JSON values");
+            throw new IllegalArgumentException(USE_SET_PROPERTY_WITH_JSON_NULL);
         }
 
         setRawProperty(name, value);
@@ -684,12 +686,61 @@ public Element setPropertyJson(String name, JsonValue value) {
     // Distinct name so setProperty("foo", null) is not ambiguous
     public Element setPropertyBean(String name, Object value) {
         if (value == null) {
-            throw new IllegalArgumentException(
-                    "setProperty(name, Json.createNull()) must be used to set a property to null");
+            throw new IllegalArgumentException(USE_SET_PROPERTY_WITH_JSON_NULL);
         }
         return setPropertyJson(name, JsonUtils.beanToJson(value));
     }
 
+    /**
+     * Sets the given property to the given list of beans or primitive values,
+     * converted to a JSON array.
+     * <p>
+     * Note that properties changed on the server are updated on the client but
+     * changes made on the client side are not reflected back to the server
+     * unless configured using
+     * {@link #addPropertyChangeListener(String, String, PropertyChangeListener)}
+     * or {@link DomListenerRegistration#synchronizeProperty(String)}.
+     *
+     * @param <T>
+     *                  the type of items in the list
+     * @param name
+     *                  the property name, not <code>null</code>
+     * @param value
+     *                  the property value, not <code>null</code>
+     * @return this element
+     */
+    public <T> Element setPropertyList(String name, List<T> value) {
+        if (value == null) {
+            throw new IllegalArgumentException(USE_SET_PROPERTY_WITH_JSON_NULL);
+        }
+
+        return setPropertyJson(name, JsonUtils.listToJson(value));
+    }
+
+    /**
+     * Sets the given property to the given map of beans or primitive values,
+     * converted to a JSON object.
+     * <p>
+     * Note that properties changed on the server are updated on the client but
+     * changes made on the client side are not reflected back to the server
+     * unless configured using
+     * {@link #addPropertyChangeListener(String, String, PropertyChangeListener)}
+     * or {@link DomListenerRegistration#synchronizeProperty(String)}.
+     *
+     * @param name
+     *                  the property name, not <code>null</code>
+     * @param value
+     *                  the property value, not <code>null</code>
+     * @return this element
+     */
+    public Element setPropertyMap(String name, Map<String, ?> value) {
+        if (value == null) {
+            throw new IllegalArgumentException(USE_SET_PROPERTY_WITH_JSON_NULL);
+        }
+
+        return setPropertyJson(name, JsonUtils.mapToJson(value));
+    }
+
     /**
      * Adds a property change listener which is triggered when the property's
      * value is updated on the server side.

flow-server/src/main/java/com/vaadin/flow/internal/JsonUtils.java

@@ -19,6 +19,7 @@
 import java.util.AbstractList;
 import java.util.Collections;
 import java.util.EnumSet;
+import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
@@ -48,6 +49,8 @@
  */
 public final class JsonUtils {
 
+    private static final String CANNOT_CONVERT_NULL_TO_A_JSON_OBJECT = "Cannot convert null to JSON";
+
     private static final ObjectMapper objectMapper = new ObjectMapper();
 
     /**
@@ -290,12 +293,44 @@ public static <T> JsonObject createObject(Map<String, T> map,
      * @return a JSON representation of the bean
      */
     public static JsonObject beanToJson(Object bean) {
-        Objects.requireNonNull(bean, "Cannot convert null to a JSON object");
+        Objects.requireNonNull(bean, CANNOT_CONVERT_NULL_TO_A_JSON_OBJECT);
 
         try {
             return Json.parse(objectMapper.writeValueAsString(bean));
         } catch (JsonProcessingException e) {
             throw new RuntimeException("Error converting bean to JSON", e);
         }
     }
+
+    /**
+     * Converts the given list to JSON.
+     *
+     * @param list
+     *                 the list to convert, not {@code null}
+     * @return a JSON representation of the bean
+     */
+    public static JsonArray listToJson(List<?> list) {
+        Objects.requireNonNull(list, CANNOT_CONVERT_NULL_TO_A_JSON_OBJECT);
+        try {
+            return Json.instance().parse(objectMapper.writeValueAsString(list));
+        } catch (JsonProcessingException e) {
+            throw new RuntimeException("Error converting list to JSON", e);
+        }
+    }
+
+    /**
+     * Converts the given map to JSON.
+     *
+     * @param map
+     *                the map to convert, not {@code null}
+     * @return a JSON representation of the bean
+     */
+    public static JsonObject mapToJson(Map<String, ?> map) {
+        Objects.requireNonNull(map, CANNOT_CONVERT_NULL_TO_A_JSON_OBJECT);
+        try {
+            return Json.instance().parse(objectMapper.writeValueAsString(map));
+        } catch (JsonProcessingException e) {
+            throw new RuntimeException("Error converting map to JSON", e);
+        }
+    }
 }

flow-server/src/test/java/com/vaadin/flow/dom/ElementTest.java

@@ -10,8 +10,10 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -50,6 +52,7 @@
 import com.vaadin.tests.util.TestUtil;
 
 import elemental.json.Json;
+import elemental.json.JsonArray;
 import elemental.json.JsonObject;
 import elemental.json.JsonValue;
 import elemental.json.impl.JreJsonObject;
@@ -573,6 +576,30 @@ public void propertyRawValues() {
         Assert.assertEquals(1.0, json.getNumber("number"), 0.0);
         Assert.assertEquals(2.3, json.getNumber("flt"), 0.0);
         Assert.assertEquals(4.56, json.getNumber("dbl"), 0.0);
+
+        List<SimpleBean> list = new ArrayList<>();
+        SimpleBean bean1 = new SimpleBean();
+        bean1.string = "bean1";
+        SimpleBean bean2 = new SimpleBean();
+        bean2.string = "bean2";
+        list.add(bean1);
+        list.add(bean2);
+        element.setPropertyList("p", list);
+        JsonArray jsonArray = (JsonArray) element.getPropertyRaw("p");
+        Assert.assertEquals("bean1",
+                jsonArray.getObject(0).getString("string"));
+        Assert.assertEquals("bean2",
+                jsonArray.getObject(1).getString("string"));
+
+        Map<String, SimpleBean> map = new HashMap<>();
+        map.put("one", bean1);
+        map.put("two", bean2);
+        element.setPropertyMap("p", map);
+        JsonObject jsonObject = (JsonObject) element.getPropertyRaw("p");
+        Assert.assertEquals("bean1",
+                jsonObject.getObject("one").getString("string"));
+        Assert.assertEquals("bean2",
+                jsonObject.getObject("two").getString("string"));
     }
 
     @Test

flow-server/src/test/java/com/vaadin/flow/internal/JsonUtilsTest.java

@@ -376,4 +376,35 @@ public void beanWithListAndMap() {
                 ((JsonObject) childBeanList.get(1)).getString("childValue"));
     }
 
+    @Test
+    public void simpleBeanListToJson() {
+        ArrayList<SimpleBean> list = new ArrayList<>();
+        SimpleBean bean1 = new SimpleBean();
+        bean1.string = "bean1";
+        SimpleBean bean2 = new SimpleBean();
+        bean2.string = "bean2";
+        list.add(bean1);
+        list.add(bean2);
+        JsonArray json = JsonUtils.listToJson(list);
+
+        Assert.assertEquals("bean1", json.getObject(0).getString("string"));
+        Assert.assertEquals("bean2", json.getObject(1).getString("string"));
+    }
+
+    @Test
+    public void simpleMapToJson() {
+        Map<String, Object> map = new HashMap<>();
+        SimpleBean bean1 = new SimpleBean();
+        bean1.string = "bean1";
+        SimpleBean bean2 = new SimpleBean();
+        bean2.string = "bean2";
+
+        map.put("one", bean1);
+        map.put("two", bean2);
+        JsonObject json = JsonUtils.mapToJson(map);
+
+        Assert.assertEquals("bean1", json.getObject("one").getString("string"));
+        Assert.assertEquals("bean2", json.getObject("two").getString("string"));
+    }
+
 }