Added Json.value(object) Method and JsonSerializable Interface

README.md

@@ -131,7 +131,22 @@ JsonValue name = Json.value("Alice");
 JsonValue points = Json.value(23);
 ```
 
-And there are methods for creating empty arrays and objects as well.
+There is also a variant of `value()` to create JSON values directly form any Java object:
+
+```java
+Set<Object> javaValues = new HashSet<Object>();
+javaValues.add("me");
+javaValues.add(3.141);
+javaValues.add(new Date());
+JsonValue jsonValues = Json.value(javaValues);
+```
+
+If you want to control the serialization of your own objects, implement the
+`JsonSerializable` interface, which is respected by the `value()` method. 
+Any other object, which cannot be directly mapped to a JSON value is converted to a string using the
+`toString()`method of the object. Circular references are not resolved.
+
+There are methods for creating empty arrays and objects as well.
 Use these together with `add` to create data structures:
 
 ```java
@@ -146,7 +161,7 @@ You can also create JSON arrays conveniently from Java arrays such as `String[]`
 
 ```java
 String[] javaNames = {"Alice", "Bob"};
-JsonArray jsonNames = Json.array(names);
+JsonArray jsonNames = Json.array(javaNames);
 ```
 
 ### Modify JSON arrays and objects

com.eclipsesource.json/src/main/java/com/eclipsesource/json/Json.java

@@ -50,6 +50,14 @@
  * String[] names = ...
  * JsonArray array = Json.array(names);
  * </pre>
+ * <p>
+ * To create a JSON array from any given Java object, you can use the <code>value(object)</code>
+ * method:
+ * </p>
+ * <pre>
+ * Object object = ...
+ * JsonValue json = Json.value(object);
+ * </pre>
  */
 public final class Json {
 
@@ -144,6 +152,21 @@ public static JsonValue value(boolean value) {
     return value ? TRUE : FALSE;
   }
 
+  /**
+   * Returns a JsonValue instance that represents the given object. If the object implements
+   * {@link JsonSerializable}, its {@link JsonSerializable#asJsonValue()} method is called and the
+   * result returned.
+   * <p>
+   * Converts null values to null literals and non-trivial objects to their string representation.
+   *
+   * @param object
+   *          the object to get a JSON representation for
+   * @return a JSON value that represents the given object
+   */
+  public static JsonValue value(Object object) {
+    return JsonBuilder.toJsonValue(object);
+  }
+
   /**
    * Creates a new empty JsonArray. This is equivalent to creating a new JsonArray using the
    * constructor.

com.eclipsesource.json/src/main/java/com/eclipsesource/json/JsonBuilder.java

@@ -0,0 +1,115 @@
+/*******************************************************************************
+ * Copyright (c) 2013, 2015 EclipseSource.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ ******************************************************************************/
+
+package com.eclipsesource.json;
+
+import java.lang.reflect.Array;
+
+import java.util.Map;
+import java.util.Map.Entry;
+
+
+/**
+ * A simple builder which allows to create a JsonValue from a java object. <b> As this is part of
+ * the minimal-json library, it is a minimal converter, and therefore does <b>not</b> resolve cyclic
+ * structures.
+ *
+ * @author Pascal Bihler
+ */
+public class JsonBuilder {
+  /**
+   * Creates a JsonValue from a Java object. If the object implements {@link JsonSerializable}, its
+   * {@link JsonSerializable#asJsonValue()} method is called and the result returned.
+   * <p>
+   * Converts null values to null literals and non-trivial objects to their string representation.
+   *
+   * @param object
+   *          The object to convert to json
+   * @return The Java object as {@link JsonValue}
+   */
+  public static JsonValue toJsonValue(final Object object) {
+    if (object == null) {
+      return Json.NULL;
+    } else if (object instanceof JsonValue) {
+      return (JsonValue) object;
+    } else if (object instanceof JsonSerializable) {
+      return ((JsonSerializable)object).asJsonValue();
+    } else if (object instanceof Boolean) {
+      return Json.value(((Boolean)object).booleanValue());
+    } else if (object instanceof Byte) {
+      return Json.value(((Byte)object).byteValue());
+    } else if (object instanceof Short) {
+      return Json.value(((Short)object).shortValue());
+    } else if (object instanceof Integer) {
+      return Json.value(((Integer)object).intValue());
+    } else if (object instanceof Long) {
+      return Json.value(((Long)object).longValue());
+    } else if (object instanceof Float) {
+      return Json.value(((Float)object).floatValue());
+    } else if (object instanceof Double) {
+      return Json.value(((Double)object).doubleValue());
+    } else if (object.getClass().isArray()) {
+      return arrayToJsonValue(object);
+    } else if (object instanceof Iterable) {
+      return iterableToJsonValue((Iterable<?>)object);
+    } else if (object instanceof Map) {
+      return mapToJsonValue((Map<?, ?>)object);
+    } else {
+      return Json.value(String.valueOf(object));
+    }
+  }
+
+  /**
+   * Creates a JsonArray from a collection object.
+   */
+  static JsonArray iterableToJsonValue(final Iterable<?> collection) {
+    final JsonArray array = new JsonArray();
+    for (final Object element : collection) {
+      array.add(toJsonValue(element));
+    }
+    return array;
+  }
+
+  /**
+   * Creates a JsonObject from a Java Map
+   */
+  static JsonObject mapToJsonValue(final Map<?, ?> map) {
+    final JsonObject object = new JsonObject();
+    for (final Entry<?, ?> entry : map.entrySet()) {
+      object.add(String.valueOf(entry.getKey()), toJsonValue(entry.getValue()));
+    }
+    return object;
+  }
+
+  /**
+   * Creates a JsonArray from an array.
+   */
+  static JsonValue arrayToJsonValue(final Object inputArray) {
+    final JsonArray array = new JsonArray();
+    final int arrayLength = Array.getLength(inputArray);
+    for (int i = 0; i < arrayLength; i++) {
+      final Object element = Array.get(inputArray, i);
+      array.add(toJsonValue(element));
+    }
+    return array;
+  }
+}

com.eclipsesource.json/src/main/java/com/eclipsesource/json/JsonSerializable.java

@@ -0,0 +1,35 @@
+/*******************************************************************************
+ * Copyright (c) 2017 EclipseSource.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ ******************************************************************************/
+package com.eclipsesource.json;
+
+/**
+ * Objects, which implement this interface, can be directly serialized as {@link JsonValue}.
+ */
+public interface JsonSerializable {
+
+  /**
+   * Serializes the object into a {@link JsonValue}
+   *
+   * @return The object as json representation
+   */
+  public JsonValue asJsonValue();
+}