Bug 152430 Key can modify to empty string
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/FilterConditionHandle.java
public void setValue1( String value1Expr )
	{
		setPropertySilently( FilterCondition.VALUE1_MEMBER, value1Expr );
	}
	/**
	 * Returns the value 2 expression of this filter condition.
	 * 
	 * @return the value 2 expression of this filter condition
	 */
	public String getValue2( )
	{
		return getStringProperty( FilterCondition.VALUE2_MEMBER );
	}
	/**
	 * Sets the value 2 expression of this filter condition.
	 * 
	 * @param value2Expr
	 *            the value 2 expression to set
	 */
	public void setValue2( String value2Expr )
	{
		setPropertySilently( FilterCondition.VALUE2_MEMBER, value2Expr );
	}
	/**
	 * Returns the column name of this filter condition.
	 * 
	 * @return <code>null</code>. NOT support any more.
	 * 
	 * @deprecated This property has been removed.
	 */