# PDAppearanceDictionary.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.annotation;

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

    import org.apache.pdfbox.pdmodel.common.COSObjectable;

    /**
     * An appearance dictionary specifying how the annotation shall be presented visually on the page.
     *
     * @author Ben Litchfield
     */
    public class PDAppearanceDictionary implements COSObjectable
    {
        private final COSDictionary dictionary;

        /**
         * Constructor for embedding.
         */
        public PDAppearanceDictionary()
        {
            dictionary = new COSDictionary();
            // the N entry is required.
            dictionary.setItem(COSName.N, new COSDictionary());
        }

        /**
         * Constructor for reading.
         *
         * @param dictionary The annotations dictionary.
         */
        public PDAppearanceDictionary(COSDictionary dictionary)
        {
            this.dictionary = dictionary;
        }

        @Override
        public COSDictionary getCOSObject()
        {
            return dictionary;
        }

        /**
         * This will return a list of appearances. In the case where there is only one appearance the map will contain one
         * entry whose key is the string "default".
         *
         * @return A list of key(java.lang.String) value(PDAppearanceStream) pairs
         */
        public PDAppearanceEntry getNormalAppearance()
        {
            COSDictionary entry = dictionary.getCOSDictionary(COSName.N);
            return entry != null ? new PDAppearanceEntry(entry) : null;
        }

        /**
         * This will set a list of appearances. If you would like to set the single appearance then you should use the key
         * "default", and when the PDF is written back to the filesystem then there will only be one stream.
         *
         * @param entry appearance stream or subdictionary
         */
        public void setNormalAppearance(PDAppearanceEntry entry)
        {
            dictionary.setItem(COSName.N, entry);
        }

        /**
         * This will set the normal appearance when there is only one appearance to be shown.
         *
         * @param ap The appearance stream to show.
         */
        public void setNormalAppearance(PDAppearanceStream ap)
        {
            dictionary.setItem(COSName.N, ap);
        }

        /**
         * This will return a list of appearances. In the case where there is only one appearance the map will contain one
         * entry whose key is the string "default". If there is no rollover appearance then the normal appearance will be
         * returned. Which means that this method will never return null.
         *
         * @return A list of key(java.lang.String) value(PDAppearanceStream) pairs
         */
        public PDAppearanceEntry getRolloverAppearance()
        {
            COSDictionary entry = dictionary.getCOSDictionary(COSName.R);
            return entry != null ? new PDAppearanceEntry(entry) : getNormalAppearance();
        }

        /**
         * This will set a list of appearances. If you would like to set the single appearance then you should use the key
         * "default", and when the PDF is written back to the filesystem then there will only be one stream.
         *
         * @param entry appearance stream or subdictionary
         */
        public void setRolloverAppearance(PDAppearanceEntry entry)
        {
            dictionary.setItem(COSName.R, entry);
        }

        /**
         * This will set the rollover appearance when there is rollover appearance to be shown.
         *
         * @param ap The appearance stream to show.
         */
        public void setRolloverAppearance(PDAppearanceStream ap)
        {
            dictionary.setItem(COSName.R, ap);
        }

        /**
         * This will return a list of appearances. In the case where there is only one appearance the map will contain one
         * entry whose key is the string "default". If there is no rollover appearance then the normal appearance will be
         * returned. Which means that this method will never return null.
         *
         * @return A list of key(java.lang.String) value(PDAppearanceStream) pairs
         */
        public PDAppearanceEntry getDownAppearance()
        {
            COSDictionary entry = dictionary.getCOSDictionary(COSName.D);
            return entry != null ? new PDAppearanceEntry(entry) : getNormalAppearance();
        }

        /**
         * This will set a list of appearances. If you would like to set the single appearance then you should use the key
         * "default", and when the PDF is written back to the filesystem then there will only be one stream.
         *
         * @param entry appearance stream or subdictionary
         */
        public void setDownAppearance(PDAppearanceEntry entry)
        {
            dictionary.setItem(COSName.D, entry);
        }

        /**
         * This will set the down appearance when there is down appearance to be shown.
         *
         * @param ap The appearance stream to show.
         */
        public void setDownAppearance(PDAppearanceStream ap)
        {
            dictionary.setItem(COSName.D, ap);
        }
    }