Class DependentSelect

java.lang.Object
fc.web.forms.Field
fc.web.forms.DependentField
fc.web.forms.DependentSelect
public final class DependentSelect extends DependentField
A dependent HTML DependentSelect field. The values of this field change based on the chosen value of some other field in the form. These new values are calculated/set on the server side.

Another good (and equally valid) approach is to instead use javascript arrays (with different sets of values) and swap out values on the client and/or use AJAX on the client side.

  • Constructor Details

    • DependentSelect

      public DependentSelect(String name)
      Creates a new select element with no initial values. Multiple selections are not initially allowed.
      Parameters:
      name - the field name

  • Method Details

    • getType

      public Field.Type getType()
      Description copied from class: Field
      Subclasses should return an appropriate Field.Type. This type is rendered as part of <input type= ...
      Specified by:
      getType in class Field

    • getValue

      public List getValue(FormData fd)
      Returns a List containing the selected options. Each object in the collection will be of type Select.Option. If there are no selected options, the returned list will be an empty list.
      Parameters:
      fd - the submited form data

    • getStringValue

      public String getStringValue(FormData fd)
      Convenience method that returns the selected option as a String. No guarantees are made as to which selection is returned when more than one selection is selected (this method is really meant for when the select only allows single selections as a dropdown).

      The returned value is of type String obtained by called the selected Select.Option's Select.Option.getValue() method.

      If there is no selection, returns null

    • getIntValue

      public int getIntValue(FormData fd)
      Convenience method that returns the single value of this field as a Integer.

      All the caveats of

      invalid reference 
      #getSingleValueAsString()
      apply.
      Throws:
      NumberFormatException - if the value could not be returned as in integer.

    • getBooleanValue

      public boolean getBooleanValue(FormData fd)
      Convenience method that returns the single value of this field as a boolean.

      All the caveats of

      invalid reference 
      #getSingleValueAsString()
      apply. In particular, the formdata should contain non-null data with at least one selection.

    • isFilled

      public boolean isFilled(FormData fd)
      Returns true if some option has been selected by the user, false otherwise. (also returns false is the specified form data is null).
      Specified by:
      isFilled in class Field

    • setValueFromSubmit

      public void setValueFromSubmit(FormData fd, jakarta.servlet.http.HttpServletRequest req)
      Description copied from class: Field
      This method sets the value of this field from the parameters obtained from the specified request. The name of the parameter to obtain this value will typically be the name of this field itself.
      Specified by:
      setValueFromSubmit in class Field
      Parameters:
      fd - the form data object to store the value in
      See Also:

    • renderImpl

      public void renderImpl(FormData fd, Writer writer) throws SQLException, IOException
      Specified by:
      renderImpl in class Field
      Throws:
      SQLException
      IOException

    • allowMultiple

      public DependentSelect allowMultiple(FormData fd, boolean allow)
      true if multiple selections are allowed, false otherwise. This value (if set) is rendered as the html MULTIPLE tag.
      Returns:
      this object for method chaining convenience

    • setSize

      public DependentSelect setSize(FormData fd, int size)
      This value (if set) is rendered as the html SIZE tag. If the list contains more options than specified by size, the browser will display the selection list with scrollbars.
      Returns:
      this object for method chaining convenience

    • setValue

      public void setValue(FormData fd, List values)
      Sets the selected values for this select in the specified form data. This is useful for showing different initial values to each user (before the form has been submitted by that user). The values are set in a newly created DependentSelect.Data object which is then stored inside the form data. Since these are set in the FormData object, these values are request specific and can differ per user.

      If the form has not been submitted, there is no form data object. A form data object should be manually created if needed for storing the value.

      Parameters:
      values - a list of Select.Option objects
      data - an existing form data object.

    • setValue

      public void setValue(DependentSelect.Data data, List values)
      Convenience method to set values in the specified DependentSelect.Data object. The following two are equivalent: 
        List values .....
  DependentSelect.Data data = new DependentSelect.Data();
  fd.putData(name, data);
  setValue(data, values);
      and 
        List values .....
  setValue(fd, values);
      Parameters:
      data - an existing DependentSelect.Data object.
      values - a list of Select.Option objects