Bug 153896 Improve the performance of BIRT datetime-converting
The current datetime converting algorithm in birt.core, xml&flatfile ODA implementations are not efficient enough.This is because we use java's SimpleDateTimeFormatter to parse ISO8601 compatible date/time values. We should write our own datatime string parser for ISO8601 datetime format.
core/org.eclipse.birt.core/src/org/eclipse/birt/core/data/DataTypeUtil.java
{
	
	private static Map dateTimeFormatholder = DateFormatUtil.getAllDateTimeFormat( );
	private static Map dateFormatHolder = DateFormatUtil.getAllDateFormat( );
	/**
	 * 
	 *
	 */
	private DateFormatHolder( )
	{
	}
	/**
	 * 
	 * @param dateStyle
	 * @param timeStyle