In the faces-config add something like this: <converter> <converter-id>NullStringConverter</converter-id> <converter-class>foo.bar.NullableStringConverter</converter-class> </converter>
Regards, Stephan ________________________________ From: Jörn Zaefferer [mailto:[EMAIL PROTECTED] Sent: Monday, March 12, 2007 4:00 PM To: MyFaces Discussion Subject: Re: StringConversion to EMPTY_STRING Could you post how you register that converter in the faces-config? Thanks. On 3/12/07, Strittmatter, Stephan < [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> > wrote: I started this, but then I spreaded this code everywhere in my managed beans and it is difficult, when you use a member of a value object directly. I created my own "NullableStringConverter" which is doing this Job now assigning it in the JSF. It is not just checking for empty String, the value has to be null-ed then also because of previous setted values: My converter looks like this: /** * Get the given value as String. In case of an empty String, null is returned. * * @param value the value of the control * @param facesContext current facesContext * @param uiComponent the uicomponent providing the value * * @return the given value as String. In case of an empty String, null is returned. * * @see javax.faces.convert.Converter#getAsObject (javax.faces.context.FacesContext, javax.faces.component.UIComponent, java.lang.String) */ public Object getAsObject(FacesContext facesContext, UIComponent uiComponent, String value) { if (facesContext == null) { throw new NullPointerException("facesContext"); } if (uiComponent == null) { throw new NullPointerException("uiComponent"); } return stringToValue(value); } /** * Convert the String to value (String or null). * * @param value the string from webcomponent * * @return the object (null if trimmed String is Empty String) */ protected Object stringToValue(String value) { if (value != null) { value = value.trim(); if (value.length() > 0) { return value + ""; } } return null; } /** * Convert the value to String for web control. * * @param value the value to be set * @param facesContext current facesContext * @param uiComponent the uicomponent to show the value * * @return the String-converted parameter * * @see javax.faces.convert.Converter#getAsString(javax.faces.context.FacesContext, javax.faces.component.UIComponent, java.lang.Object) */ public String getAsString(FacesContext facesContext, UIComponent uiComponent, Object value) { if (facesContext == null) { throw new NullPointerException("facesContext"); } if (uiComponent == null) { throw new NullPointerException("uiComponent"); } return valueToString(value); } /** * Converts the value to HTMLized String. * * @param value the object to be converted * * @return String representation */ protected String valueToString(Object value) { if (value == null) { return ""; } if (value instanceof String) { return (String) value; } return value + ""; } ________________________________ From: Jörn Zaefferer [mailto:[EMAIL PROTECTED] Sent: Monday, March 12, 2007 9:29 AM To: MyFaces Discussion Subject: Re: StringConversion to EMPTY_STRING You could add a check for the value to set in each modifier, something like this: public void setName(String newName) { if ( !"".equasl(newName) ) { name = newName; } } Still quite cumbersome... On 3/12/07, Strittmatter, Stephan <[EMAIL PROTECTED]> wrote: Hi Mike, thanks for this info. Then I have to add my converter manually to every control :-/ -----Original Message----- From: Mike Kienenberger [mailto:[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED] > ] Sent: Thursday, March 08, 2007 7:42 PM To: MyFaces Discussion Subject: Re: StringConversion to EMPTY_STRING The JSF spec says that components will return the empty string, not null. There is no way to specify a converter-by-type for String in JSF 1.1. You can specify String converters for JSF 1.2. https://javaserverfaces-spec-public.dev.java.net/issues/show_bug.cgi?id= <https://javaserverfaces-spec-public.dev.java.net/issues/show_bug.cgi?id=> 131 On 3/8/07, Strittmatter, Stephan <[EMAIL PROTECTED] > wrote: > Hello all, > > I had several times problems with inputText Components which are having > Strings as input. > If there is nothing typed in, the BackingBean get an EMPTY_STRING (""), > but I would expect > null there? Is this the common behaviour? > > For Workaround, I created my own converter adding for every control. Is > there a way to define > it for all String-Controls by default on the orther hand? > > Regards, > > Stephan >
