java: adds NullableTemplate

java/src/main/java/org/msgpack/template/NullableTemplate.java

@@ -0,0 +1,56 @@
+//
+// MessagePack for Java
+//
+// Copyright (C) 2009-2010 FURUHASHI Sadayuki
+//
+//    Licensed under the Apache License, Version 2.0 (the "License");
+//    you may not use this file except in compliance with the License.
+//    You may obtain a copy of the License at
+//
+//        http://www.apache.org/licenses/LICENSE-2.0
+//
+//    Unless required by applicable law or agreed to in writing, software
+//    distributed under the License is distributed on an "AS IS" BASIS,
+//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//    See the License for the specific language governing permissions and
+//    limitations under the License.
+//
+package org.msgpack.template;
+
+import java.io.IOException;
+import org.msgpack.*;
+
+public class NullableTemplate implements Template {
+	private Template elementTemplate;
+
+	public NullableTemplate(Template elementTemplate) {
+		this.elementTemplate = elementTemplate;
+	}
+
+	public Template getElementTemplate() {
+		return elementTemplate;
+	}
+
+	public void pack(Packer pk, Object target) throws IOException {
+		if(target == null) {
+			pk.packNil();
+		} else {
+			elementTemplate.pack(pk, target);
+		}
+	}
+
+	public Object unpack(Unpacker pac) throws IOException, MessageTypeException {
+		if(pac.tryUnpackNull()) {
+			return null;
+		}
+		return elementTemplate.unpack(pac);
+	}
+
+	public Object convert(MessagePackObject from) throws MessageTypeException {
+		if(from.isNil()) {
+			return null;
+		}
+		return elementTemplate.convert(from);
+	}
+}
+