Bug 206850 [Regression] Error pops up when select value for a map or highlight rule to group header row [0302]
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/elements/structures/StyleRule.java
}
	/**
	 * Set expression for the first operand.
	 * 
	 * @param value
	 *            the first operand expression.
	 */
	public void setValue1( String value )
	{	
		if ( value == null )
		{
			setProperty( VALUE1_MEMBER, null );
			return;
		}
		List valueList = new ArrayList( );
		valueList.add( value );
		setProperty( VALUE1_MEMBER, valueList );
	}
	/**
	 * Sets the value 1 expression.
	 * 
	 * @param value1List
	 *            the value 1 expression list to set
	 */
	public void setValue1( List value1List )
	{
		setProperty( VALUE1_MEMBER, value1List );
	}
	/**
	 * Returns the expression for the second operand.