# COSNumber.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.cos;

    import java.io.IOException;

    /**
     * This class represents an abstract number in a PDF document.
     *
     * @author Ben Litchfield
     */
    public abstract class COSNumber extends COSBase
    {
        /**
         * This will get the float value of this number.
         *
         * @return The float value of this object.
         */
        public abstract float floatValue();

        /**
         * This will get the integer value of this number.
         *
         * @return The integer value of this number.
         */
        public abstract int intValue();

        /**
         * This will get the long value of this number.
         *
         * @return The long value of this number.
         */
        public abstract long longValue();

        /**
         * This factory method will get the appropriate number object.
         *
         * @param number The string representation of the number.
         *
         * @return A number object, either float or int.
         *
         * @throws IOException If the string is not a number.
         */
        public static COSNumber get( String number ) throws IOException
        {
            if (number.length() == 1)
            {
                char digit = number.charAt(0);
                if ('0' <= digit && digit <= '9')
                {
                    return COSInteger.get((long) digit - '0');
                }
                if (digit == '-' || digit == '.')
                {
                    // See https://issues.apache.org/jira/browse/PDFBOX-592
                    return COSInteger.ZERO;
                }
                throw new IOException("Not a number: " + number);
            }
            if (isFloat(number))
            {
                return new COSFloat(number);
            }
            try
            {
                return COSInteger.get(Long.parseLong(number));
            }
            catch (NumberFormatException e)
            {
                // check if the given string could be a number at all
                String numberString = number.startsWith("+") || number.startsWith("-")
                        ? number.substring(1) : number;
                if (!numberString.matches("[0-9]*"))
                {
                    throw new IOException("Not a number: " + number);
                }
                // return a limited COSInteger value which is marked as invalid
                return number.startsWith("-") ? COSInteger.OUT_OF_RANGE_MIN
                        : COSInteger.OUT_OF_RANGE_MAX;
            }
        }

        private static boolean isFloat( String number )
        {
            int length = number.length();
            for (int i = 0; i < length; i++)
            {
                char digit = number.charAt(i);
                if (digit == '.' || digit == 'e')
                {
                    return true;
                }
            }
            return false;
        }
    }