Bug 152430 Key can modify to empty string
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/FilterConditionHandle.java
public String getColumn( )
	{
		return null;
	}
	/**
	 * Sets the column name of this filter condition. NOT support any more.
	 * 
	 * @param column
	 *            the column name to set
	 * 
	 * @deprecated This property has been removed.
	 * 
	 */
	public void setColumn( String column )
	{
	}
	/**
	 * Returns the filter expression.
	 * 
	 * @return the expression for the filter.
	 * 
	 * @deprecated Replaced by the method {@link #getExpr()}
	 */
	public String getFilterExpr( )
	{
		return getExpr( );
	}
	/**
	 * Sets the filter expression.
	 *