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
if ( source == null )
			return null;
		if ( source instanceof Boolean )
		{
			return (Boolean) source;
		}
		else if ( source instanceof Number )
		{
			
			int intValue = ( (Number) source ).intValue( );
			if ( intValue == 0 )
				return new Boolean( false );
			return new Boolean( true );
		}
		else if ( source instanceof String )
		{
			if ( ( (String) source ).equalsIgnoreCase( "true" ) )
				return Boolean.TRUE;
			else if ( ( (String) source ).equalsIgnoreCase( "false" ) )
				return Boolean.FALSE;
			else
			{
				try
				{
					if ( Integer.parseInt( (String) source ) == 0 )
						return Boolean.FALSE;
					else
						return Boolean.TRUE;
				}
				catch ( NumberFormatException e )