Inclusion of a serializer for ZonedDateTime

Signed-off-by: Fabio José <fabiojose@gmail.com>

api/src/main/java/io/cloudevents/impl/ZonedDateTimeSerializer.java

@@ -0,0 +1,46 @@
+/**
+ * Copyright 2018 The CloudEvents Authors
+ *
+ * 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 io.cloudevents.impl;
+
+import java.io.IOException;
+import java.time.ZonedDateTime;
+import java.time.format.DateTimeFormatter;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.databind.SerializerProvider;
+import com.fasterxml.jackson.databind.ser.std.StdSerializer;
+
+public class ZonedDateTimeSerializer extends StdSerializer<ZonedDateTime> {
+
+	private static final long serialVersionUID = 6245182835980474796L;
+
+	public ZonedDateTimeSerializer() {
+		this(null, false);
+	}
+
+	protected ZonedDateTimeSerializer(Class<?> t, boolean dummy) {
+		super(t, dummy);
+	}
+
+	@Override
+	public void serialize(ZonedDateTime time, JsonGenerator generator,
+			SerializerProvider provider) throws IOException {
+
+		generator.writeString(time.format(DateTimeFormatter.ISO_OFFSET_DATE_TIME));
+
+	}
+
+}