public StringFilter() 
{

}

Default constructor.

 public Object clone() throws CloneNotSupportedException 
{
    final StringFilter f = (StringFilter) super.clone();
    if (source != null)
    {
      f.source = (DataSource) source.clone();
    }
    return f;
}

Clones the filter.

 public DataSource getDataSource() 
{
    return source;
}

Returns the data source for this filter.

 public FormatSpecification getFormatString(ExpressionRuntime runtime,
    Element element,
    FormatSpecification formatSpecification) 
{
    if (source instanceof RawDataSource)
    {
      final RawDataSource rds = (RawDataSource) source;
      return rds.getFormatString(runtime, element, formatSpecification);
    }
    if (formatSpecification == null)
    {
      formatSpecification = new FormatSpecification();
    }
    formatSpecification.redefine(FormatSpecification.TYPE_UNDEFINED, null);
    return formatSpecification;
}

 public String getNullValue() 
{
    return nullvalue;
}

Returns the string used to represent a null value.

 public Object getRawValue(ExpressionRuntime runtime,
    Element element) 
{
    if (source instanceof RawDataSource)
    {
      final RawDataSource rawDataSource = (RawDataSource) source;
      return rawDataSource.getRawValue(runtime, element);
    }
    return source.getValue(runtime, element);
}

 public Object getValue(ExpressionRuntime runtime,
    Element element) 
{
    final DataSource ds = getDataSource();
    if (ds == null)
    {
      return getNullValue();
    }
    final Object o = ds.getValue(runtime, element);
    if (o == null)
    {
      return getNullValue();
    }
    // String is final, so it is safe to do this ...
    if (StringFilter.STRING_CLASSNAME.equals(o.getClass().getName()))
    {
      return o;
    }
    if (o instanceof char[])
    {
      return new String ((char[]) o);
    }
    if (o instanceof Clob)
    {
      return readClob((Clob) o);
    }
    return String.valueOf(o);
}

Returns the value obtained from the data source.

The filter ensures that the returned value is a String, even though the return type is Object (as required by the DataSource interface).

 public  void setDataSource(DataSource ds) 
{
    if (ds == null)
    {
      throw new NullPointerException();
    }
    source = ds;
}

Sets the data source for this filter.

 public  void setNullValue(String nullvalue) 
{
    this.nullvalue = nullvalue;
}

Sets the string used to represent a null value.