Five Minute Tutorial

Version 3 by Robin Shen
on Feb 10, 2010 04:25.

<< Changes from 2 to 3

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Version 4 by Robin Shen
on Feb 10, 2010 04:26.

Changes from 4 to 5 >>

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		We demonstrate usage of this tool with a simple tutorial. Assume a _Task_ class below with a _prioritized_ field indicating whether it is a prioritized task:
		{code}
		package example;

		public class Task {
		public boolean prioritized;
		}
		{code}
		With XStream, we can serialize object of this class to XML like below:
		{code}
		Task task = new Task();
		task.setPrioritized(true);
		String xml = new XStream().toXML(task);
		saveXmlToFileOrDatabase(xml);
		{code}
		Resulting XML will be:
		{code}
		<example.Task>
		<prioritized>true</prioritized>
		</example.Task>
		{code}
		And you can deserialize the XML to get back task object:
		{code}
		String xml = readXmlFromFileOrDatabase();
		Task task = (Task)(new XStream(new DomDriver()).fromXML(xml));
		{code}
		Everything is fine. Now we find a prioritized flag is not enough, so we enhance the Task class to use a numeric priority field ranging from 1 to 10:
		{code}
		package example;

		public class Task {
		public int priority;
		}
		{code}
		However deserialization of previously saved xml is no longer possible since the new Task class is no longer compatible.
		However deserialization of previously saved xml is no longer possible since the new Task class is not compatible with previous version.