# PDRadioButton.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 java.util.ArrayList;
    import java.util.List;

    import org.apache.pdfbox.cos.COSDictionary;
    import org.apache.pdfbox.cos.COSName;
    import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationWidget;

    /**
     * Radio button fields contain a set of related buttons that can each be on or off.
     *
     * @author sug
     */
    public final class PDRadioButton extends PDButton
    {
        /**
         * A Ff flag.
         */
        private static final int FLAG_NO_TOGGLE_TO_OFF = 1 << 14;

        /**
         * @see PDField#PDField(PDAcroForm)
         *
         * @param acroForm The acroform.
         */
        public PDRadioButton(PDAcroForm acroForm)
        {
            super(acroForm);
            getCOSObject().setFlag(COSName.FF, FLAG_RADIO, true);
        }

        /**
         * Constructor.
         *
         * @param acroForm The form that this field is part of.
         * @param field the PDF object to represent as a field.
         * @param parent the parent node of the node
         */
        PDRadioButton(PDAcroForm acroForm, COSDictionary field, PDNonTerminalField parent)
        {
            super(acroForm, field, parent);
        }

        /**
         * From the PDF Spec <br>
         * If set, a group of radio buttons within a radio button field that use the same value for the on state will turn
         * on and off in unison; that is if one is checked, they are all checked. If clear, the buttons are mutually
         * exclusive (the same behavior as HTML radio buttons).
         *
         * @param radiosInUnison The new flag for radiosInUnison.
         */
        public void setRadiosInUnison(boolean radiosInUnison)
        {
            getCOSObject().setFlag(COSName.FF, FLAG_RADIOS_IN_UNISON, radiosInUnison);
        }

        /**
         *
         * @return true If the flag is set for radios in unison.
         */
        public boolean isRadiosInUnison()
        {
            return getCOSObject().getFlag(COSName.FF, FLAG_RADIOS_IN_UNISON);
        }

        /**
         * This will get the selected index.
         * <p>
         * A RadioButton might have multiple same value options which are not selected jointly if
         * they are not set in unison {@link #isRadiosInUnison()}.</p>
         *
         * <p>
         * The method will return the first selected index or -1 if no option is selected.</p>
         *
         * @return the first selected index or -1.
         */
        public int getSelectedIndex()
        {
            int idx = 0;
            for (PDAnnotationWidget widget : getWidgets())
            {
                if (!COSName.Off.equals(widget.getAppearanceState()))
                {
                    return idx;
                }
                idx ++;
            }
            return -1;
        }

        /**
         * This will get the selected export values.
         * <p>
         * A RadioButton might have an export value to allow field values
         * which can not be encoded as PDFDocEncoding or for the same export value
         * being assigned to multiple RadioButtons in a group.<br>
         * To define an export value the RadioButton must define options {@link #setExportValues(List)}
         * which correspond to the individual items within the RadioButton.</p>
         * <p>
         * The method will either return the corresponding values from the options entry or in case there
         * is no such entry the fields value</p>
         *
         * @return the export value of the field.
         */
        public List<String> getSelectedExportValues()
        {
            List<String> exportValues = getExportValues();
            List<String> selectedExportValues = new ArrayList<>();
            if (exportValues.isEmpty())
            {
                selectedExportValues.add(getValue());
                return selectedExportValues;
            }
            else
            {
                String fieldValue = getValue();
                int idx = 0;
                for (String onValue : getOnValues())
                {
                    if (onValue.compareTo(fieldValue) == 0)
                    {
                        selectedExportValues.add(exportValues.get(idx));
                    }
                    ++idx;
                }
                return selectedExportValues;
            }
        }
    }