UnquietCode · April 8, 2019 19:06 · Dec 14, 2013 · Dec 14, 2013 · Dec 14, 2013
diff --git a/Test.java b/Test.java
@@ -1,5 +1,3 @@
-package com.sb.data.api;
-
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.ObjectNode;
 

diff --git a/Test.java b/Test.java
@@ -0,0 +1,75 @@
+package com.sb.data.api;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+
+import java.io.ByteArrayOutputStream;
+
+/**
+ * @author Ben Fagin
+ * @version 2013-12-13
+ */
+public class Test {
+
+	interface Point extends Model {
+		int getX();
+		void setX(int x);
+
+		int getY();
+		void setY(int y);
+
+		Nub getNub();
+		void setNub(Nub nub);
+	}
+
+	interface Nub extends Model {
+		void setThing(int thing);
+		int getThing();
+	}
+
+	public static void main(String[] args) throws Exception {
+		final ObjectMapper jsonMapper = new ObjectMapper();
+		jsonMapper.registerModule(new MapperModule());
+
+		ObjectNode data = jsonMapper.createObjectNode();
+		data.put("x", 100);
+		data.put("y", 200);
+		data.putObject("nub").put("thing", 300);
+
+		Point point = jsonMapper.reader(Point.class).readValue(data);
+
+		System.out.println(point.getX());
+		System.out.println(point.getY());
+		System.out.println(point.getNub().getThing());
+
+		point.setX(111);
+		point.setY(222);
+		point.setNub(new Nub() {
+			int val = 333;
+
+			public void setThing(int thing) {
+				val = thing;
+			}
+
+			public int getThing() {
+				return val;
+			}
+		});
+
+		ByteArrayOutputStream os = new ByteArrayOutputStream();
+
+		System.out.println(point.getX());
+		System.out.println(point.getY());
+		System.out.println(point.getNub().getThing());
+
+		jsonMapper.writerWithType(Point.class).writeValue(os, point);
+		System.out.println(os.toString());
+		os.reset();
+
+		point.getNub().setThing(400);
+		System.out.println(point.getNub().getThing());
+
+		jsonMapper.writerWithType(Point.class).writeValue(os, point);
+		System.out.println(os.toString());
+	}
+}
diff --git a/MapperModule.java b/MapperModule.java
@@ -0,0 +1,44 @@
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.core.Version;
+import com.fasterxml.jackson.databind.*;
+import com.fasterxml.jackson.databind.deser.Deserializers;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+
+import java.io.IOException;
+import java.util.Iterator;
+
+/**
+* @author Ben Fagin
+* @version 2013-12-13
+*/
+public class MapperModule extends Module {
+
+	@Override
+	public String getModuleName() {
+		return "ModelMapper";
+	}
+
+	@Override
+	public Version version() {
+		return new Version(2, 0, 0, null, null, null);
+	}
+
+	@Override
+	public void setupModule(SetupContext context) {
+		context.addDeserializers(new Deserializers.Base() {
+			public @Override JsonDeserializer<?> findBeanDeserializer(final JavaType type, DeserializationConfig config, BeanDescription beanDesc) throws JsonMappingException {
+				if (Model.class.isAssignableFrom(type.getRawClass())) {
+					return new JsonDeserializer<Object>() {
+						public @Override Object deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException, JsonProcessingException {
+							Iterator<ObjectNode> obj = jp.readValuesAs(ObjectNode.class);
+							return ModelMapper.map(type.getRawClass(), obj.next());
+						}
+					};
+				}
+
+				return super.findBeanDeserializer(type, config, beanDesc);
+			}
+		});
+	}
+}
diff --git a/Model.java b/Model.java
@@ -0,0 +1,9 @@
+/**
+ * Marker interface for all model objects.
+ *
+ * @author Ben Fagin
+ * @version 2013-12-13
+ */
+interface Model {
+	// nothing here, as this is just a marker
+}
diff --git a/ModelMapper.java b/ModelMapper.java
@@ -0,0 +1,78 @@
+import com.fasterxml.jackson.databind.*;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import com.fasterxml.jackson.databind.node.POJONode;
+
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.Method;
+import java.lang.reflect.Proxy;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * @author Ben Fagin
+ * @version 2013-12-13
+ */
+public class ModelMapper {
+
+	@SuppressWarnings("unchecked")
+	public static <T> T map(Class<T> klaus, final ObjectNode data) {
+		checkNotNull(data);
+		checkArgument(klaus != null && klaus.isInterface(), "interfaces only please");
+
+		return (T) Proxy.newProxyInstance(Thread.currentThread().getContextClassLoader(), new Class[]{klaus}, new InvocationHandler() {
+			public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
+				String property = method.getName().substring(3);
+				property = new String(new char[]{property.charAt(0)}).toLowerCase() + property.substring(1);
+
+				// getter
+				if (method.getName().startsWith("get") && method.getParameterTypes().length == 0) {
+					return getProperty(data, property, method);
+				}
+
+				// setter
+				if (method.getName().startsWith("set") && method.getParameterTypes().length == 1) {
+					data.putPOJO(property, args[0]);
+					return null;
+				}
+
+				throw new RuntimeException("Not a property: "+method.getName());
+			}
+		});
+	}
+
+	private static Object getProperty(ObjectNode data, String property, Method method) {
+		Class<?> returnType = method.getReturnType();
+		JsonNode value = data.get(property);
+
+		if (Integer.class.equals(returnType) || int.class.equals(returnType)) {
+			return value.asInt();
+		}
+
+		else if (Double.class.equals(returnType) || double.class.equals(returnType)) {
+			return value.asDouble();
+		}
+
+		else if (Long.class.equals(returnType) || long.class.equals(returnType)) {
+			return value.asLong();
+		}
+
+		else if (Boolean.class.equals(returnType) || boolean.class.equals(returnType)) {
+			return value.asBoolean();
+		}
+
+		else if (String.class.equals(returnType)) {
+			return value.asText();
+		}
+
+		else if (returnType.isInterface() && Model.class.isAssignableFrom(returnType)) {
+			if (value.isObject()) {
+				return map(returnType, (ObjectNode) value);
+			} else if (value.isPojo()) {
+				return ((POJONode) value).getPojo();
+			}
+		}
+
+		throw new RuntimeException("Unknown return type: "+returnType);
+	}
+}
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