# PDDocumentInformation.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;

    import java.util.Calendar;
    import java.util.Set;
    import java.util.TreeSet;

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

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

    /**
     * This is the document metadata.  Each getXXX method will return the entry if
     * it exists or null if it does not exist.  If you pass in null for the setXXX
     * method then it will clear the value.
     *
     * @author Ben Litchfield
     * @author Gerardo Ortiz
     *
     */
    public class PDDocumentInformation implements COSObjectable
    {
        private final COSDictionary info;

        /**
         * Default Constructor.
         */
        public PDDocumentInformation()
        {
            info = new COSDictionary();
        }

        /**
         * Constructor that is used for a preexisting dictionary.
         *
         * @param dic The underlying dictionary.
         */
        public PDDocumentInformation( COSDictionary dic )
        {
            info = dic;
        }

        /**
         * This will get the underlying dictionary that this object wraps.
         *
         * @return The underlying info dictionary.
         */
        @Override
        public COSDictionary getCOSObject()
        {
            return info;
        }

        /**
         * Return the properties String value.
         * <p>
         * Allows to retrieve the
         * low level date for validation purposes.
         * </p>
         *
         * @param propertyKey the dictionaries key
         * @return the properties value
         */
         public Object getPropertyStringValue(String propertyKey)
         {
             return info.getString(propertyKey);
         }

        /**
         * This will get the title of the document.  This will return null if no title exists.
         *
         * @return The title of the document.
         */
        public String getTitle()
        {
            return info.getString( COSName.TITLE );
        }

        /**
         * This will set the title of the document.
         *
         * @param title The new title for the document.
         */
        public void setTitle( String title )
        {
            info.setString( COSName.TITLE, title );
        }

        /**
         * This will get the author of the document.  This will return null if no author exists.
         *
         * @return The author of the document.
         */
        public String getAuthor()
        {
            return info.getString( COSName.AUTHOR );
        }

        /**
         * This will set the author of the document.
         *
         * @param author The new author for the document.
         */
        public void setAuthor( String author )
        {
            info.setString( COSName.AUTHOR, author );
        }

        /**
         * This will get the subject of the document.  This will return null if no subject exists.
         *
         * @return The subject of the document.
         */
        public String getSubject()
        {
            return info.getString( COSName.SUBJECT );
        }

        /**
         * This will set the subject of the document.
         *
         * @param subject The new subject for the document.
         */
        public void setSubject( String subject )
        {
            info.setString( COSName.SUBJECT, subject );
        }

        /**
         * This will get the keywords of the document.  This will return null if no keywords exists.
         *
         * @return The keywords of the document.
         */
        public String getKeywords()
        {
            return info.getString( COSName.KEYWORDS );
        }

        /**
         * This will set the keywords of the document.
         *
         * @param keywords The new keywords for the document.
         */
        public void setKeywords( String keywords )
        {
            info.setString( COSName.KEYWORDS, keywords );
        }

        /**
         * This will get the creator of the document.  This will return null if no creator exists.
         *
         * @return The creator of the document.
         */
        public String getCreator()
        {
            return info.getString( COSName.CREATOR );
        }

        /**
         * This will set the creator of the document.
         *
         * @param creator The new creator for the document.
         */
        public void setCreator( String creator )
        {
            info.setString( COSName.CREATOR, creator );
        }

        /**
         * This will get the producer of the document.  This will return null if no producer exists.
         *
         * @return The producer of the document.
         */
        public String getProducer()
        {
            return info.getString( COSName.PRODUCER );
        }

        /**
         * This will set the producer of the document.
         *
         * @param producer The new producer for the document.
         */
        public void setProducer( String producer )
        {
            info.setString( COSName.PRODUCER, producer );
        }

        /**
         * This will get the creation date of the document.  This will return null if no creation date exists.
         *
         * @return The creation date of the document.
         */
        public Calendar getCreationDate()
        {
            return info.getDate( COSName.CREATION_DATE );
        }

        /**
         * This will set the creation date of the document.
         *
         * @param date The new creation date for the document.
         */
        public void setCreationDate( Calendar date )
        {
            info.setDate( COSName.CREATION_DATE, date );
        }

        /**
         * This will get the modification date of the document.  This will return null if no modification date exists.
         *
         * @return The modification date of the document.
         */
        public Calendar getModificationDate()
        {
            return info.getDate( COSName.MOD_DATE );
        }

        /**
         * This will set the modification date of the document.
         *
         * @param date The new modification date for the document.
         */
        public void setModificationDate( Calendar date )
        {
            info.setDate( COSName.MOD_DATE, date );
        }

        /**
         * This will get the trapped value for the document.
         * This will return null if one is not found.
         *
         * @return The trapped value for the document.
         */
        public String getTrapped()
        {
            return info.getNameAsString( COSName.TRAPPED );
        }

        /**
         * This will get the keys of all metadata information fields for the document.
         *
         * @return all metadata key strings.
         * @since Apache PDFBox 1.3.0
         */
        public Set<String> getMetadataKeys()
        {
            Set<String> keys = new TreeSet<>();
            for (COSName key : info.keySet())
            {
                keys.add(key.getName());
            }
            return keys;
        }

        /**
         *  This will get the value of a custom metadata information field for the document.
         *  This will return null if one is not found.
         *
         * @param fieldName Name of custom metadata field from pdf document.
         *
         * @return String Value of metadata field
         */
        public String getCustomMetadataValue(String fieldName)
        {
            return info.getString( fieldName );
        }

        /**
         * Set the custom metadata value.
         *
         * @param fieldName The name of the custom metadata field.
         * @param fieldValue The value to the custom metadata field.
         */
        public void setCustomMetadataValue( String fieldName, String fieldValue )
        {
            info.setString( fieldName, fieldValue );
        }

        /**
         * This will set the trapped of the document.  This will be
         * 'True', 'False', or 'Unknown'.
         *
         * @param value The new trapped value for the document.
         *
         * @throws IllegalArgumentException if the parameter is invalid.
         */
        public void setTrapped( String value )
        {
            if( value != null &&
                !value.equals( "True" ) &&
                !value.equals( "False" ) &&
                !value.equals( "Unknown" ) )
            {
                throw new IllegalArgumentException( "Valid values for trapped are " +
                                            "'True', 'False', or 'Unknown'" );
            }

            info.setName( COSName.TRAPPED, value );
        }
    }