# PDPageLabelRange.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.common;

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

    /**
     * Contains information for a page label range.
     *
     * @author Igor Podolskiy
     *
     * @see PDPageLabels
     *
     */
    public class PDPageLabelRange implements COSObjectable
    {

        private final COSDictionary root;

        // Page label dictionary (PDF32000-1:2008 Section 12.4.2, Table 159)
        private static final COSName KEY_START = COSName.ST;
        private static final COSName KEY_PREFIX = COSName.P;
        private static final COSName KEY_STYLE = COSName.S;

        // Style entry values (PDF32000-1:2008 Section 12.4.2, Table 159)

        /**
         * Decimal page numbering style (1, 2, 3, ...).
         */
        public static final String STYLE_DECIMAL = "D";

        /**
         * Roman numbers (upper case) numbering style (I, II, III, IV, ...).
         */
        public static final String STYLE_ROMAN_UPPER = "R";

        /**
         * Roman numbers (lower case) numbering style (i, ii, iii, iv, ...).
         */
        public static final String STYLE_ROMAN_LOWER = "r";

        /**
         * Letter (upper case) numbering style (A, B, ..., Z, AA, BB, ..., ZZ, AAA,
         * ...).
         */
        public static final String STYLE_LETTERS_UPPER = "A";

        /**
         * Letter (lower case) numbering style (a, b, ..., z, aa, bb, ..., zz, aaa,
         * ...).
         */
        public static final String STYLE_LETTERS_LOWER = "a";

        /**
         * Creates a new empty page label range object.
         */
        public PDPageLabelRange()
        {
            this(new COSDictionary());
        }

        /**
         * Creates a new page label range object from the given dictionary.
         *
         * @param dict
         *            the base dictionary for the new object.
         */
        public PDPageLabelRange(COSDictionary dict)
        {
            root = dict;
        }

        /**
         * Returns the underlying dictionary.
         *
         * @return the underlying dictionary.
         */
        @Override
        public COSDictionary getCOSObject()
        {
            return root;
        }

        /**
         * Returns the numbering style for this page range.
         *
         * @return one of the STYLE_* constants
         */
        public String getStyle()
        {
            return root.getNameAsString(KEY_STYLE);
        }

        /**
         * Sets the numbering style for this page range.
         *
         * @param style
         *            one of the STYLE_* constants or {@code null} if no page
         *            numbering is desired.
         */
        public void setStyle(String style)
        {
            if (style != null)
            {
                root.setName(KEY_STYLE, style);
            }
            else
            {
                root.removeItem(KEY_STYLE);
            }
        }

        /**
         * Returns the start value for page numbering in this page range.
         *
         * @return a positive integer the start value for numbering.
         */
        public int getStart()
        {
            return root.getInt(KEY_START, 1);
        }

        /**
         * Sets the start value for page numbering in this page range.
         *
         * @param start
         *            a positive integer representing the start value.
         * @throws IllegalArgumentException
         *             if {@code start} is not a positive integer
         */
        public void setStart(int start)
        {
            if (start <= 0)
            {
                throw new IllegalArgumentException(
                        "The page numbering start value must be a positive integer");
            }
            root.setInt(KEY_START, start);
        }

        /**
         * Returns the page label prefix for this page range.
         *
         * @return the page label prefix for this page range, or {@code null} if no
         *         prefix has been defined.
         */
        public String getPrefix()
        {
            return root.getString(KEY_PREFIX);
        }

        /**
         * Sets the page label prefix for this page range.
         *
         * @param prefix
         *            the page label prefix for this page range, or {@code null} to
         *            unset the prefix.
         */
        public void setPrefix(String prefix)
        {
            if (prefix != null)
            {
                root.setString(KEY_PREFIX, prefix);
            }
            else
            {
                root.removeItem(KEY_PREFIX);
            }
        }
    }