Bug 204229 [Automation][Regression]Exception is thrown when preview reportdesign in webviewer
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/document/RDSave.java
import org.eclipse.birt.data.engine.api.IScriptExpression;
import org.eclipse.birt.data.engine.api.querydefn.QueryDefinition;
import org.eclipse.birt.data.engine.core.DataException;
import org.eclipse.birt.data.engine.i18n.ResourceConstants;
import org.eclipse.birt.data.engine.impl.document.stream.StreamManager;
import org.eclipse.birt.data.engine.impl.document.stream.VersionManager;
import org.eclipse.birt.data.engine.odi.IResultIterator;
/**
 * Save expression value of every row into report document. The output format in
 * stream is, <expressCount, [expression id, expression value]*>.
 * 
 * When no value of one row is saved, the expressionCount will automatically be
 * ouptput as 0. It will happen when caller does not call getValue on this row
 * or call skipToEnd method.
 */
class RDSave implements IRDSave
{
		 
	private DataEngineContext context;
	
	
	private OutputStream rowExprsOs;
	private OutputStream rowLenOs;
	
	
	private int rowCount;
	
	private IBaseQueryDefinition queryDefn;
	private Set exprNameSet;