Fix #66 (add Json.mapOfFrom())

jr-objects/src/main/java/com/fasterxml/jackson/jr/ob/JSON.java

@@ -919,6 +919,33 @@ public Map<String,Object> mapFrom(Object source) throws IOException, JSONObjectE
         }
     }
 
+    /**
+     * Read method for reading a {@link Map} of {@code type} (usually POJO) values.
+     *
+     * @since 2.10
+     */
+    @SuppressWarnings("unchecked")
+    public <T> Map<String,T> mapOfFrom(Class<T> type, Object source) throws IOException, JSONObjectException
+    {
+        if (source instanceof JsonParser) {
+            JsonParser p = _initForReading((JsonParser) source);
+            Map<?,?> result = _readerForOperation(p).readMapOf(type);
+            p.clearCurrentToken();
+            return (Map<String,T>) result;
+        }
+        JsonParser p = _parser(source);
+        try {
+            _initForReading(_config(p));
+            Map<?,?> result = _readerForOperation(p).readMapOf(type);
+            JsonParser p0 = p;
+            p = null;
+            _close(p0, null);
+            return (Map<String,T>) result;
+        } catch (Exception e) {
+            return _closeWithError(p, e);
+        }
+    }
+
     public <T> T beanFrom(Class<T> type, Object source) throws IOException, JSONObjectException
     {
         if (source instanceof JsonParser) {

jr-objects/src/main/java/com/fasterxml/jackson/jr/ob/ValueIterator.java

@@ -131,7 +131,7 @@ public class ValueIterator<T> implements Iterator<T>, Closeable
 
     /**
      * @param managedParser Whether we "own" the {@link JsonParser} passed or not:
-     *   if true, it was created by {@link ObjectReader} and code here needs to
+     *   if true, it was created by {@code Json} and code here needs to
      *   close it; if false, it was passed by calling code and should not be
      *   closed by iterator.
      */

jr-objects/src/main/java/com/fasterxml/jackson/jr/ob/impl/JSONReader.java

@@ -265,8 +265,8 @@ public <T> T[] readArrayOf(Class<T> type) throws IOException {
 
     /**
      * Method for reading a JSON Array from input and building a {@link java.util.List}
-     * out of it. Note that if input does NOT contain a
-     * JSON Array, {@link JSONObjectException} will be thrown.
+     * out of it, binding values into specified {@code type}.
+     * Note that if input does NOT contain a JSON Array, {@link JSONObjectException} will be thrown.
      */
     @SuppressWarnings("unchecked")
     public <T> List<T> readListOf(Class<T> type) throws IOException
@@ -282,7 +282,29 @@ public <T> List<T> readListOf(Class<T> type) throws IOException
         return (List<T>) new CollectionReader(List.class, _readerLocator.findReader(type))
                 .read(this, _parser);
     }
-
+
+    /**
+     * Method for reading a JSON Object from input and building a {@link java.util.Map}
+     * out of it, binding values into specified {@code type}.
+     * Note that if input does NOT contain a JSON Object, {@link JSONObjectException} will be thrown.
+     *
+     * @since 2.10
+     */
+    @SuppressWarnings("unchecked")
+    public <T> Map<String, T> readMapOf(Class<T> type) throws IOException
+    {
+        JsonToken t = _parser.getCurrentToken();
+        if (t == JsonToken.VALUE_NULL) {
+            return null;
+        }
+        if (t != JsonToken.START_OBJECT) {
+            throw JSONObjectException.from(_parser,
+                    "Can not read a Map: expect to see START_OBJECT ('{'), instead got: "+ValueReader._tokenDesc(_parser));
+        }
+        return (Map<String, T>) new MapReader(Map.class, _readerLocator.findReader(type))
+                .read(this, _parser);
+    }
+
     /*
     /**********************************************************************
     /* Internal methods; overridable for custom coercions

jr-objects/src/main/java/com/fasterxml/jackson/jr/ob/impl/POJODefinition.java

@@ -37,9 +37,6 @@ public class POJODefinition
     public final Constructor<?> stringCtor;
     public final Constructor<?> longCtor;
 
-    /**
-     * Constructors used for serialization use case
-     */
     public POJODefinition(Class<?> type, Prop[] props,
             Constructor<?> defaultCtor0, Constructor<?> stringCtor0, Constructor<?> longCtor0)
     {

jr-objects/src/main/java/com/fasterxml/jackson/jr/ob/impl/ValueReaderLocator.java

@@ -162,7 +162,13 @@ public ValueReaderLocator perOperationInstance(JSONReader r, int features) {
 
     /**
      * Method used during deserialization to find handler for given
-     * non-generic type.
+     * non-generic type: will first check for already resolved (and cached) readers
+     * -- and return if one found -- and then if no cached reader found, create
+     * one, cache, return.
+     *
+     * @param raw Type-erased type of value to find reader for
+     *
+     * @return ValueReader to use for given type
      */
     public ValueReader findReader(Class<?> raw)
     {
@@ -182,7 +188,12 @@ public ValueReader findReader(Class<?> raw)
     }
 
     /**
-     * Factory method for creating standard readers of any declared type
+     * Factory method for creating standard readers of any declared type.
+     *
+     * @param contextType Context for resolving generic type parameters
+     * @param type Type-erased type of value to construct reader for
+     * @param genericType Full (possibly) generic type of value to construct reader for (important
+     *   for {@link java.util.Map}, {@link java.util.Collection}).
      */
     protected ValueReader createReader(Class<?> contextType, Class<?> type, Type genericType)
     {

jr-objects/src/test/java/com/fasterxml/jackson/jr/ob/ReadBeansTest.java

@@ -122,7 +122,7 @@ public void testPOJOWithMap() throws Exception
         assertEquals(2, map.stuff.size());
         assertEquals(Integer.valueOf(4), map.stuff.get("b"));
     }
-    
+
     public void testSimpleBeanCollections() throws Exception
     {
         final String INPUT = aposToQuotes("["
@@ -153,6 +153,23 @@ public void testSimpleBeanCollections() throws Exception
         assertEquals("Bacon", beans2.get(1).name.last);
     }
 
+    // @since 2.10
+    public void testSimpleBeanMaps() throws Exception
+    {
+        final String INPUT = aposToQuotes("{ 'first':"
+                +"{'name':{'first':'Bob','last':'Burger'},'x':13}"
+                +", 'second':{'x':-145,'name':{'first':'Billy','last':'Bacon'}}"
+                +"}");
+        Map<String, TestBean> stuff = JSON.std.mapOfFrom(TestBean.class, INPUT);
+        assertEquals(2, stuff.size());
+        assertNotNull(stuff.get("first"));
+        TestBean bean2 = stuff.get("second");
+        assertNotNull(bean2);
+        assertEquals(-145, bean2.x);
+        assertEquals("Billy", bean2.name.first);
+        assertEquals("Bacon", bean2.name.last);
+    }
+
     public void testJvmSerializersPOJO() throws Exception
     {
         MediaItem.Content content = new MediaItem.Content();

jr-stree/src/main/java/com/fasterxml/jackson/jr/stree/JacksonJrsTreeCodec.java

@@ -118,13 +118,25 @@ public JsonParser treeAsTokens(TreeNode node) {
      */
 
     /**
+     * Factory method for constructing node to represent Boolean values.
+     *
+     * @param state Whether to create {@code Boolean.TRUE} or {@code Boolean.FALSE} node
+     *
+     * @return Node instance for given boolean value
+     *
      * @since 2.8
      */
     public JrsBoolean booleanNode(boolean state) {
          return state? JrsBoolean.TRUE : JrsBoolean.FALSE;
     }
 
     /**
+     * Factory method for constructing node to represent String values.
+     *
+     * @param text String value for constructed node to contain
+     *
+     * @return Node instance for given text value
+     *
      * @since 2.8
      */
     public JrsString stringNode(String text) {
@@ -135,6 +147,12 @@ public JrsString stringNode(String text) {
     }
 
     /**
+     * Factory method for constructing node to represent String values.
+     *
+     * @param nr Numeric value for constructed node to contain
+     *
+     * @return Node instance for given numeric value
+     *
      * @since 2.8
      */
     public JrsNumber numberNode(Number nr) {

release-notes/VERSION-2.x

@@ -9,6 +9,8 @@ Project: jackson-jr
 #60: Add support for reading "root value" streams (linefeed separated/concatenated)
 #63: Change default for `JSON.Feature.USE_FIELDS` to `true` (from false) in 2.10
 #65: Allow registration of custom readers, writers (to support 3rd party, custom types)
+#66: Add `Json.mapOfFrom(Class)` to support binding POJO-valued maps
+ (suggested by ocind@github)
 - Add `JrsNull` node type for `jr-stree` package
 - Add JDK9+ `module-info.class` using Moditect
 - Update Retrofit2 version (2.0.0 -> 2.5.0)