# PDNumberTreeNode.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 java.io.IOException;
    import java.util.ArrayList;
    import java.util.Collections;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;

    import org.apache.commons.logging.Log;
    import org.apache.commons.logging.LogFactory;
    import org.apache.pdfbox.cos.COSArray;
    import org.apache.pdfbox.cos.COSBase;
    import org.apache.pdfbox.cos.COSDictionary;
    import org.apache.pdfbox.cos.COSInteger;
    import org.apache.pdfbox.cos.COSName;
    import org.apache.pdfbox.cos.COSNull;

    /**
     * This class represents a PDF Number tree. See the PDF Reference 1.7 section
     * 7.9.7 for more details.
     *
     * @author Ben Litchfield,
     * @author Igor Podolskiy
     */
    public class PDNumberTreeNode implements COSObjectable
    {
        private static final Log LOG = LogFactory.getLog( PDNumberTreeNode.class );

        private final COSDictionary node;
        private Class<? extends COSObjectable> valueType = null;

        /**
         * Constructor.
         *
         * @param valueClass The PD Model type of object that is the value.
         */
        public PDNumberTreeNode( Class<? extends COSObjectable> valueClass )
        {
            node = new COSDictionary();
            valueType = valueClass;
        }

        /**
         * Constructor.
         *
         * @param dict The dictionary that holds the number information.
         * @param valueClass The PD Model type of object that is the value.
         */
        public PDNumberTreeNode( COSDictionary dict, Class<? extends COSObjectable> valueClass )
        {
            node = dict;
            valueType = valueClass;
        }

        /**
         * Convert this standard java object to a COS object.
         *
         * @return The cos object that matches this Java object.
         */
        @Override
        public COSDictionary getCOSObject()
        {
            return node;
        }

        /**
         * Return the children of this node.  This list will contain PDNumberTreeNode objects.
         *
         * @return The list of children or null if there are no children.
         */
        public List<PDNumberTreeNode> getKids()
        {
            List<PDNumberTreeNode> retval = null;
            COSArray kids = node.getCOSArray(COSName.KIDS);
            if( kids != null )
            {
                List<PDNumberTreeNode> pdObjects = new ArrayList<>();
                for( int i=0; i<kids.size(); i++ )
                {
                    pdObjects.add( createChildNode( (COSDictionary)kids.getObject(i) ) );
                }
                retval = new COSArrayList<>(pdObjects,kids);
            }

            return retval;
        }

        /**
         * Set the children of this number tree.
         *
         * @param kids The children of this number tree. These have to be in sorted order. Because of
         * that, it is usually easier to call {@link #setNumbers(Map)} with a map and pass a single
         * element list here.
         */
        public void setKids( List<? extends PDNumberTreeNode> kids )
        {
            if (kids != null && !kids.isEmpty())
            {
                PDNumberTreeNode firstKid = kids.get(0);
                PDNumberTreeNode lastKid = kids.get(kids.size() - 1);
                Integer lowerLimit = firstKid.getLowerLimit();
                setLowerLimit(lowerLimit);
                Integer upperLimit = lastKid.getUpperLimit();
                setUpperLimit(upperLimit);
                node.setItem(COSName.KIDS, new COSArray(kids));
            }
            else if ( node.getDictionaryObject( COSName.NUMS ) == null )
            {
                // Remove limits if there are no kids and no numbers set.
                node.setItem( COSName.LIMITS, null);
                node.setItem(COSName.KIDS, null);
            }
        }

        /**
         * Returns the value corresponding to an index in the number tree.
         *
         * @param index The index in the number tree.
         *
         * @return The value corresponding to the index.
         *
         * @throws IOException If there is a problem creating the values.
         */
        public Object getValue(Integer index) throws IOException
        {
            Map<Integer, COSObjectable> numbers = getNumbers();
            if (numbers != null)
            {
                return numbers.get(index);
            }
            Object retval = null;
            List<PDNumberTreeNode> kids = getKids();
            if (kids != null)
            {
                for (int i = 0; i < kids.size() && retval == null; i++)
                {
                    PDNumberTreeNode childNode = kids.get(i);
                    if (childNode.getLowerLimit().compareTo(index) <= 0 &&
                        childNode.getUpperLimit().compareTo(index) >= 0)
                    {
                        retval = childNode.getValue(index);
                    }
                }
            }
            else
            {
                LOG.warn("NumberTreeNode does not have \"nums\" nor \"kids\" objects.");
            }
            return retval;
        }

        /**
         * This will return a map of numbers.  The key will be a java.lang.Integer, the value will
         * depend on where this class is being used.
         *
         * @return A map of COS objects.
         *
         * @throws IOException If there is a problem creating the values.
         */
        public Map<Integer,COSObjectable> getNumbers()  throws IOException
        {
            Map<Integer, COSObjectable> indices = null;
            COSArray numbersArray = node.getCOSArray(COSName.NUMS);
            if (numbersArray != null)
            {
                indices = new HashMap<>();
                if (numbersArray.size() % 2 != 0)
                {
                    LOG.warn("Numbers array has odd size: " + numbersArray.size());
                }
                for (int i = 0; i + 1 < numbersArray.size(); i += 2)
                {
                    COSBase base = numbersArray.getObject(i);
                    if (!(base instanceof COSInteger))
                    {
                        LOG.error("page labels ignored, index " + i + " should be a number, but is " + base);
                        return null;
                    }
                    COSInteger key = (COSInteger) base;
                    COSBase cosValue = numbersArray.getObject(i + 1);
                    indices.put(key.intValue(), cosValue == null ? null : convertCOSToPD(cosValue));
                }
                indices = Collections.unmodifiableMap(indices);
            }
            return indices;
        }

        /**
         * Method to convert the COS value in the number tree to the PD Model object. The default
         * implementation will simply use reflection to create the correct object type. Subclasses can
         * do whatever they want.
         *
         * @param base The COS object to convert.
         * @return The converted PD Model object.
         * @throws IOException If there is an error during creation.
         */
        protected COSObjectable convertCOSToPD(COSBase base) throws IOException
        {
            // valueType (passed in constructor here) must have a constructor of type of COSBase as parameter
            try
            {
                return valueType.getDeclaredConstructor(base.getClass()).newInstance(base);
            }
            catch( Exception t )
            {
                throw new IOException("Error while trying to create value in number tree:" + t.getMessage(), t);
            }
        }

        /**
         * Create a child node object.
         *
         * @param dic The dictionary for the child node object to refer to.
         * @return The new child node object.
         */
        protected PDNumberTreeNode createChildNode( COSDictionary dic )
        {
            return new PDNumberTreeNode(dic,valueType);
        }

        /**
         * Set the numbers for this node. This method will set the appropriate upper and lower limits
         * based on the keys in the map and take care of the ordering.
         *
         * @param numbers The map of numbers to objects, or <code>null</code> for nothing.
         */
        public void setNumbers( Map<Integer, ? extends COSObjectable> numbers )
        {
            if( numbers == null )
            {
                node.setItem( COSName.NUMS, (COSObjectable)null );
                node.setItem( COSName.LIMITS, (COSObjectable)null);
            }
            else
            {
                List<Integer> keys = new ArrayList<>( numbers.keySet() );
                Collections.sort( keys );
                COSArray array = new COSArray();
                for (Integer key : keys)
                {
                    array.add( COSInteger.get( key ) );
                    COSObjectable obj = numbers.get( key );
                    array.add(obj == null ? COSNull.NULL : obj);
                }
                Integer lower = null;
                Integer upper = null;
                if (!keys.isEmpty())
                {
                    lower = keys.get( 0 );
                    upper = keys.get( keys.size()-1 );
                }
                setUpperLimit( upper );
                setLowerLimit( lower );
                node.setItem( COSName.NUMS, array );
            }
        }

        /**
         * Get the highest value for a key in the number map.
         *
         * @return The highest value for a key in the map.
         */
        public Integer getUpperLimit()
        {
            Integer retval = null;
            COSArray arr = node.getCOSArray(COSName.LIMITS);
            if( arr != null && arr.get(1) != null )
            {
                retval = arr.getInt( 1 );
            }
            return retval;
        }

        /**
         * Set the highest value for the key in the map.
         *
         * @param upper The new highest value for a key in the map.
         */
        private void setUpperLimit( Integer upper )
        {
            COSArray arr = node.getCOSArray(COSName.LIMITS);
            if( arr == null )
            {
                arr = new COSArray();
                arr.add( null );
                arr.add( null );
                node.setItem( COSName.LIMITS, arr );
            }
            if ( upper != null)
            {
                arr.setInt( 1, upper);
            }
            else
            {
                arr.set( 1, null );
            }
        }

        /**
         * Get the lowest value for a key in the number map.
         *
         * @return The lowest value for a key in the map.
         */
        public Integer getLowerLimit()
        {
            Integer retval = null;
            COSArray arr = node.getCOSArray(COSName.LIMITS);
            if( arr != null && arr.get(0) != null )
            {
                retval = arr.getInt( 0 );
            }
            return retval;
        }

        /**
         * Set the lowest value for the key in the map.
         *
         * @param lower The new lowest value for a key in the map.
         */
        private void setLowerLimit( Integer lower )
        {
            COSArray arr = node.getCOSArray(COSName.LIMITS);
            if( arr == null )
            {
                arr = new COSArray();
                arr.add( null );
                arr.add( null );
                node.setItem( COSName.LIMITS, arr );
            }
            if ( lower != null )
            {
                arr.setInt( 0, lower);
            }
            else
            {
                arr.set( 0, null );
            }
        }
    }