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> import java.io.IOException;
> import java.io.ObjectInputStream;
> import java.io.ObjectOutputStream;
> import java.io.Serializable;
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< public class DataContext implements QueryEngine {
---
> public class DataContext implements QueryEngine, Serializable{
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<     protected QueryEngine parent;
---
>     protected transient QueryEngine parent; //Will not be directly serialized - see read/writeObject for details
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<     class RelationshipDataSource implements ToManyListDataSource {
---
>     class RelationshipDataSource implements ToManyListDataSource, Serializable {
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>     
>      private void writeObject(ObjectOutputStream out) throws IOException {
> 		//If the "parent" of this datacontext is a DataDomain, then just write the
> 		// name of it.  Then when deser happens, we can get back the DataDomain by name, 
> 		// from the shared configuration (which will either load it if need be, or return 
> 		// an existing one.
> 		out.defaultWriteObject();
> 		if(this.parent instanceof DataDomain) {
> 			DataDomain domain=(DataDomain) this.parent;
> 			out.writeObject(domain.getName());
> 		} else {
> 			out.writeObject(this.parent); //Hope that whatever this.parent is, that it is Serializable
> 		}
>      }
>      
> 	 private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
> 	 	boolean failed=false;
> 	 	in.defaultReadObject();
> 	 	Object value=in.readObject();
> 	 	if(value instanceof QueryEngine) {
> 	 		//Must be a real QueryEngine object - use it
> 	 		this.parent=(QueryEngine)value;
> 	 	} else if (value instanceof String) {
> 	 		//Must be the name of a DataDomain - use it
> 	 		this.parent=Configuration.getSharedConfig().getDomain((String)value);
> 	 		if(this.parent==null) {
> 	 			failed=true;
> 	 		}
> 	 	} else {
> 	 		failed=true;
> 	 	}
> 	 	if(failed) {
> 	 		throw new IOException("Parent attribute of DataContext was neither a QueryEngine nor " +
> 	 		"the name of a valid DataDomain:"+value);
> 	 	}
> 
>      }
>