public synchronized void add(File file){
  if (file == null)   return;
  File[] newValue=new File[value.length + 1];
  System.arraycopy(value,0,newValue,0,value.length);
  newValue[value.length]=file;
  setValue(newValue);
}

public synchronized void add ( File file ) { if ( file == null ) return ; File [ ] newValue = new File [ value . length + 1 ] ; System . arraycopy ( value , 0 , newValue , 0 , value . length ) ; newValue [ value . length ] = file ; setValue ( newValue ) ; }
mutator for this setting .
