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package se.l4.commons.serialization.standard;

import java.io.IOException;

import se.l4.commons.serialization.QualifiedName;
import se.l4.commons.serialization.SerializationException;
import se.l4.commons.serialization.Serializer;
import se.l4.commons.serialization.SerializerCollection;
import se.l4.commons.serialization.SerializerFormatDefinition;
import se.l4.commons.serialization.format.StreamingInput;
import se.l4.commons.serialization.format.StreamingOutput;
import se.l4.commons.serialization.format.Token;
import se.l4.commons.serialization.format.ValueType;

/**
 * Serializer that will attempt to dynamically resolve serializers based on
 * their name.
 * 
 * @author Andreas Holstenson
 *
 */
public class DynamicSerializer
	implements Serializer
{
	private final SerializerCollection collection;
	private final SerializerFormatDefinition formatDefinition;

	public DynamicSerializer(SerializerCollection collection)
	{
		this.collection = collection;
		
		formatDefinition = SerializerFormatDefinition.builder()
			.field("namespace").using(ValueType.STRING)
			.field("name").using(ValueType.STRING)
			.field("value").using(SerializerFormatDefinition.any())
			.build();
	}
	
	@Override
	public Object read(StreamingInput in)
		throws IOException
	{
		// Read start of object
		in.next(Token.OBJECT_START);
		
		String namespace = "";
		String name = null;
		
		Object result = null;
		boolean resultRead = false;

		/*
		 * Loop through values, first reading namespace and name. If value
		 * is encountered before name abort.
		 */
		while(in.peek() != Token.OBJECT_END)
		{
			in.next(Token.KEY);
			String key = in.getString();
			
			if("namespace".equals(key))
			{
				in.next(Token.VALUE);
				
				String value = in.getString();
				namespace = value;
			}
			else if("name".equals(key))
			{
				in.next(Token.VALUE);
				String value = in.getString();
				
				name = value;
			}
			else if("value".equals(key))
			{
				if(name == null)
				{
					throw new SerializationException("Name of type must come before dynamic value");
				}
				
				resultRead = true;
				
				Serializer serializer = collection.find(namespace, name);
				if(serializer == null)
				{
					// TODO: What should we do if we have no serializer?
					in.skipValue();
					continue;
				}
				
				result = serializer.read(in);
			}
			else
			{
				in.skipValue();
			}
		}
		
		if(! resultRead)
		{
			throw new SerializationException("Dynamic serialization requires a value");
		}
		
		in.next(Token.OBJECT_END);
		return result;
	}
	
	@Override
	@SuppressWarnings({ "rawtypes", "unchecked" })
	public void write(Object object, String name, StreamingOutput stream)
		throws IOException
	{
		Serializer serializer = collection.find(object.getClass());
		QualifiedName qname = collection.findName(serializer);
		if(qname == null)
		{
			throw new SerializationException("Tried to use dynamic serialization for " + object.getClass() + ", but type has no name");
		}
		
		stream.writeObjectStart(name);
		
		if(! qname.getNamespace().equals(""))
		{
			stream.write("namespace", qname.getNamespace());
		}
		
		stream.write("name", qname.getName());
		
		serializer.write(object, "value", stream);
		
		stream.writeObjectEnd(name);
	}
	
	@Override
	public SerializerFormatDefinition getFormatDefinition()
	{
		return formatDefinition;
	}
}
    

    

    

            

    

            



    
    






    
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