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
String[] dateFormatPattern = {
				"yyyy-MM-dd HH:mm:ss.S z",
				"yyyy-MM-dd HH:mm:ss.Sz",
				"yyyy-MM-dd HH:mm:ss.S",
				"yyyy-MM-dd HH:mm:ss z",
				"yyyy-MM-dd HH:mm:ssz",
				"yyyy-MM-dd HH:mm:ss",
				"yyyy-MM-dd HH:mm z",
				"yyyy-MM-dd HH:mmz",
				"yyyy-MM-dd HH:mm",
				"yyyy-MM-dd",
				"yyyy-MM",
				"yyyy"	
		};
		simpleDateFormatter = new SimpleDateFormat[dateFormatPattern.length];
		for ( int i = 0; i < dateFormatPattern.length; i++ )
		{
			simpleDateFormatter[i] = new SimpleDateFormat( dateFormatPattern[i] );
			simpleDateFormatter[i].setLenient( false );
		}
	}
	/**
	 * convert an object to given type
	 * Types supported:
	 * 	 	DataType.INTEGER_TYPE
	 * 		DataType.DECIMAL_TYPE
	 * 		DataType.BOOLEAN_TYPE
	 * 		DataType.DATE_TYPE
	 * 		DataType.DOUBLE_TYPE
	 * 		DataType.STRING_TYPE