# PDFieldFactory.java

    /*
     * Licensed to the Apache Software Foundation (ASF) under one or more
     * contributor license agreements.  See the NOTICE file distributed with
     * this work for additional information regarding copyright ownership.
     * The ASF licenses this file to You under the Apache License, Version 2.0
     * (the "License"); you may not use this file except in compliance with
     * the License.  You may obtain a copy of the License at
     *
     *      http://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing, software
     * distributed under the License is distributed on an "AS IS" BASIS,
     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     * See the License for the specific language governing permissions and
     * limitations under the License.
     */

    package org.apache.pdfbox.pdmodel.interactive.form;

    import org.apache.pdfbox.cos.COSArray;
    import org.apache.pdfbox.cos.COSBase;
    import org.apache.pdfbox.cos.COSDictionary;
    import org.apache.pdfbox.cos.COSName;

    /**
     * A PDField factory.
     */
    public final class PDFieldFactory
    {

        private static final String FIELD_TYPE_TEXT = "Tx";
        private static final String FIELD_TYPE_BUTTON = "Btn";
        private static final String FIELD_TYPE_CHOICE = "Ch";
        private static final String FIELD_TYPE_SIGNATURE = "Sig";

        private PDFieldFactory()
        {
        }

        /**
         * Creates a COSField subclass from the given field.
         *
         * @param form the form that the field is part of
         * @param field the dictionary representing a field element
         * @param parent the parent node of the node to be created
         * @return the corresponding PDField instance
         */
        public static PDField createField(PDAcroForm form, COSDictionary field, PDNonTerminalField parent)
        {
            // Test if we have a non terminal field first as it might have
            // properties which do apply to other fields
            // A non terminal fields has Kids entries which do have
            // a field name (other than annotations)
            if (field.containsKey(COSName.KIDS))
            {
                COSArray kids = field.getCOSArray(COSName.KIDS);
                if (kids != null && kids.size() > 0)
                {
                    for (int i = 0; i < kids.size(); i++)
                    {
                        COSBase kid = kids.getObject(i);
                        if (kid instanceof COSDictionary && ((COSDictionary) kid).getString(COSName.T) != null)
                        {
                            return new PDNonTerminalField(form, field, parent);
                        }
                    }
                }
            }

            String fieldType = findFieldType(field);

            if (FIELD_TYPE_CHOICE.equals(fieldType))
            {
                return createChoiceSubType(form, field, parent);
            }
            else if (FIELD_TYPE_TEXT.equals(fieldType))
            {
                return new PDTextField(form, field, parent);
            }
            else if (FIELD_TYPE_SIGNATURE.equals(fieldType))
            {
                return new PDSignatureField(form, field, parent);
            }
            else if (FIELD_TYPE_BUTTON.equals(fieldType))
            {
                return createButtonSubType(form, field, parent);
            }
            else
            {
                // an erroneous non-field object, see PDFBOX-2885
                return null;
            }
        }

        private static PDField createChoiceSubType(PDAcroForm form, COSDictionary field,
                                                   PDNonTerminalField parent)
        {
            int flags = field.getInt(COSName.FF, 0);
            if ((flags & PDChoice.FLAG_COMBO) != 0)
            {
                return new PDComboBox(form, field, parent);
            }
            else
            {
                return new PDListBox(form, field, parent);
            }
        }

        private static PDField createButtonSubType(PDAcroForm form, COSDictionary field,
                                                   PDNonTerminalField parent)
        {
            int flags = field.getInt(COSName.FF, 0);
            // 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.
            if ((flags & PDButton.FLAG_RADIO) != 0)
            {
                return new PDRadioButton(form, field, parent);
            }
            else if ((flags & PDButton.FLAG_PUSHBUTTON) != 0)
            {
                return new PDPushButton(form, field, parent);
            }
            else
            {
                return new PDCheckBox(form, field, parent);
            }
        }

        private static String findFieldType(COSDictionary dic)
        {
            String retval = dic.getNameAsString(COSName.FT);
            if (retval == null)
            {
                COSDictionary base = dic.getCOSDictionary(COSName.PARENT, COSName.P);
                return base != null ?  findFieldType(base):null;
            }
            return retval;
        }
    }