propertyfactory.java

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/* ====================================================================
   Copyright 2002-2004   Apache Software Foundation

   Licensed 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.poi.poifs.property;

import java.io.IOException;

import java.util.*;

import org.apache.poi.poifs.common.POIFSConstants;
import org.apache.poi.poifs.storage.ListManagedBlock;

/**
 * Factory for turning an array of RawDataBlock instances containing
 * Proprty data into an array of proper Property objects.
 *
 * The array produced may be sparse, in that any portion of data that
 * should correspond to a Property, but which does not map to a proper
 * Property (i.e., a DirectoryProperty, DocumentProperty, or
 * RootProperty) will get mapped to a null Property in the array.
 *
 * @author Marc Johnson (mjohnson at apache dot org)
 */

class PropertyFactory
{

    // no need for an accessible constructor
    private PropertyFactory()
    {
    }

    /**
     * Convert raw data blocks to an array of Property's
     *
     * @param blocks to be converted
     *
     * @return the converted List of Property objects. May contain
     *         nulls, but will not be null
     *
     * @exception IOException if any of the blocks are empty
     */

    static List convertToProperties(ListManagedBlock [] blocks)
        throws IOException
    {
        List properties = new ArrayList();

        for (int j = 0; j < blocks.length; j++)
        {
            byte[] data           = blocks[ j ].getData();
            int    property_count = data.length
                                    / POIFSConstants.PROPERTY_SIZE;
            int    offset         = 0;

            for (int k = 0; k < property_count; k++)
            {
                switch (data[ offset + PropertyConstants.PROPERTY_TYPE_OFFSET ])
                {

                    case PropertyConstants.DIRECTORY_TYPE :
                        properties
                            .add(new DirectoryProperty(properties.size(),
                                                       data, offset));
                        break;

                    case PropertyConstants.DOCUMENT_TYPE :
                        properties.add(new DocumentProperty(properties.size(),
                                                            data, offset));
                        break;

                    case PropertyConstants.ROOT_TYPE :
                        properties.add(new RootProperty(properties.size(),
                                                        data, offset));
                        break;

                    default :
                        properties.add(null);
                        break;
                }
                offset += POIFSConstants.PROPERTY_SIZE;
            }
        }
        return properties;
    }
}   // end package scope class PropertyFactory