# PDOptionalContentMembershipDictionary.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.graphics.optionalcontent;

    import java.util.ArrayList;
    import java.util.List;
    import org.apache.pdfbox.cos.COSArray;
    import org.apache.pdfbox.cos.COSBase;
    import org.apache.pdfbox.cos.COSDictionary;
    import org.apache.pdfbox.cos.COSName;
    import org.apache.pdfbox.pdmodel.documentinterchange.markedcontent.PDPropertyList;

    /**
     * An optional content membership dictionary (OCMD).
     *
     * @author Tilman Hausherr
     */
    public class PDOptionalContentMembershipDictionary extends PDPropertyList
    {
        /**
         * Creates a new optional content membership dictionary (OCMD).
         */
        public PDOptionalContentMembershipDictionary()
        {
            this.dict.setItem(COSName.TYPE, COSName.OCMD);
        }

        /**
         * Creates a new instance based on a given {@link COSDictionary}.
         * @param dict the dictionary
         */
        public PDOptionalContentMembershipDictionary(COSDictionary dict)
        {
            super(dict);
            if (!dict.getItem(COSName.TYPE).equals(COSName.OCMD))
            {
                throw new IllegalArgumentException(
                        "Provided dictionary is not of type '" + COSName.OCMD + "'");
            }
        }

        /**
         * Get a list of optional content groups.
         *
         * @return List of optional content groups, never null.
         */
        public List<PDPropertyList> getOCGs()
        {
            List<PDPropertyList> list = new ArrayList<>();
            COSBase base = dict.getDictionaryObject(COSName.OCGS);
            if (base instanceof COSDictionary)
            {
                list.add(PDPropertyList.create((COSDictionary) base));
            }
            else if (base instanceof COSArray)
            {
                COSArray ar = (COSArray) base;
                for (int i = 0; i < ar.size(); ++i)
                {
                    COSBase elem = ar.getObject(i);
                    if (elem instanceof COSDictionary)
                    {
                        list.add(PDPropertyList.create((COSDictionary) elem));
                    }
                }
            }
            return list;
        }

        /**
         * Set optional content groups as a list.
         *
         * @param ocgs list of optional content groups to set.
         */
        public void setOCGs(List<PDPropertyList> ocgs)
        {
            COSArray ar = new COSArray();
            for (PDPropertyList prop : ocgs)
            {
                ar.add(prop);
            }
            dict.setItem(COSName.OCGS, ar);
        }

        /**
         * Get the visibility policy name. Valid names are AllOff, AllOn, AnyOff, AnyOn (default).
         *
         * @return the visibility policy, never null.
         */
        public COSName getVisibilityPolicy()
        {
            return dict.getCOSName(COSName.P, COSName.ANY_ON);
        }

        /**
         * Sets the visibility policy name. Valid names are AllOff, AllOn, AnyOff, AnyOn (default).
         * @param visibilityPolicy
         */
        public void setVisibilityPolicy(COSName visibilityPolicy)
        {
            dict.setItem(COSName.P, visibilityPolicy);
        }

        //TODO support /VE some day
    }