/**
* This method creates a COSField subclass from the given field. The field is a PDF Dictionary
* object that must represent a field element. - othewise null is returned
*
* @param acroForm The form that the field will be part of.
* @param field The dictionary representing a field element
* @return a subclass to COSField according to the kind of field passed to createField
* @throws IOException If there is an error determining the field type.
*/
public static PDField createField(PDAcroForm acroForm, COSDictionary field) throws IOException {
PDField pdField = new PDUnknownField(acroForm, field);
if (isButton(pdField)) {
int flags = pdField.getFieldFlags();
// BJL, I have found that the radio flag bit is not always set
// and that sometimes there is just a kids dictionary.
// so, if there is a kids dictionary then it must be a radio button
// group.
COSArray kids = (COSArray) field.getDictionaryObject(COSName.getPDFName("Kids"));
if (kids != null || isRadio(flags)) {
pdField = new PDRadioCollection(acroForm, field);
} else if (isPushButton(flags)) {
pdField = new PDPushButton(acroForm, field);
} else {
pdField = new PDCheckbox(acroForm, field);
}
} else if (isChoiceField(pdField)) {
pdField = new PDChoiceField(acroForm, field);
} else if (isTextbox(pdField)) {
pdField = new PDTextbox(acroForm, field);
} else if (isSignature(pdField)) {
pdField = new PDSignature(acroForm, field);
} else {
// do nothing and return an unknown field type.
}
return pdField;
}
/**
* This method determines if the given field is a button.
*
* @param field the field to determine
* @return the result of the determination
* @throws IOException If there is an error determining the field type.
*/
private static boolean isButton(PDField field) throws IOException {
String ft = field.findFieldType();
boolean retval = FIELD_TYPE_BTN.equals(ft);
List kids = field.getKids();
if (ft == null && kids != null && kids.size() > 0) {
// sometimes if it is a button the type is only defined by one
// of the kids entries
Object obj = kids.get(0);
COSDictionary kidDict = null;
if (obj instanceof PDField) {
kidDict = ((PDField) obj).getDictionary();
} else if (obj instanceof PDAnnotationWidget) {
kidDict = ((PDAnnotationWidget) obj).getDictionary();
} else {
throw new IOException("Error:Unexpected type of kids field:" + obj);
}
retval = isButton(new PDUnknownField(field.getAcroForm(), kidDict));
}
return retval;
}
/**
* This method determines if the given field is a Textbox.
*
* @param field the field to determine
* @return the result of the determination
*/
private static boolean isTextbox(PDField field) throws IOException {
return FIELD_TYPE_TX.equals(field.findFieldType());
}
/**
* This method determines if the given field is a signature.
*
* @param field the field to determine
* @return the result of the determination
*/
private static boolean isSignature(PDField field) throws IOException {
return FIELD_TYPE_SIG.equals(field.findFieldType());
}
/**
* This method determines if the given field is a choicefield Choicefields are either listboxes or
* comboboxes.
*
* @param field the field to determine
* @return the result of the determination
*/
private static boolean isChoiceField(PDField field) throws IOException {
return FIELD_TYPE_CH.equals(field.findFieldType());
}