blocklistimpl.java

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/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2003 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache POI" must not be used to endorse or promote products
 *    derived from this software without prior written permission. For
 *    written permission, please contact [e-mail].
 *
 * 5. Products derived from this software may not be called "Apache",
 *    "Apache POI", nor may "Apache" appear in their name, without
 *    prior written permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

package org.apache.poi.poifs.storage;

import java.io.*;

import java.util.*;

/**
 * A simple implementation of BlockList
 *
 * @author Marc Johnson (mjohnson at apache dot org
 */

class BlockListImpl
    implements BlockList
{
    private ListManagedBlock[]         _blocks;
    private BlockAllocationTableReader _bat;

    /**
     * Constructor BlockListImpl
     */

    protected BlockListImpl()
    {
        _blocks = new ListManagedBlock[ 0 ];
        _bat    = null;
    }

    /**
     * provide blocks to manage
     *
     * @param blocks blocks to be managed
     */

    protected void setBlocks(final ListManagedBlock [] blocks)
    {
        _blocks = blocks;
    }

    /* ********** START implementation of BlockList ********** */

    /**
     * remove the specified block from the list
     *
     * @param index the index of the specified block; if the index is
     *              out of range, that's ok
     */

    public void zap(final int index)
    {
        if ((index >= 0) && (index < _blocks.length))
        {
            _blocks[ index ] = null;
        }
    }

    /**
     * remove and return the specified block from the list
     *
     * @param index the index of the specified block
     *
     * @return the specified block
     *
     * @exception IOException if the index is out of range or has
     *            already been removed
     */

    public ListManagedBlock remove(final int index)
        throws IOException
    {
        ListManagedBlock result = null;

        try
        {
            result = _blocks[ index ];
            if (result == null)
            {
                throw new IOException("block[ " + index
                                      + " ] already removed");
            }
            _blocks[ index ] = null;
        }
        catch (ArrayIndexOutOfBoundsException ignored)
        {
            throw new IOException("Cannot remove block[ " + index
                                  + " ]; out of range");
        }
        return result;
    }

    /**
     * get the blocks making up a particular stream in the list. The
     * blocks are removed from the list.
     *
     * @param startBlock the index of the first block in the stream
     *
     * @return the stream as an array of correctly ordered blocks
     *
     * @exception IOException if blocks are missing
     */

    public ListManagedBlock [] fetchBlocks(final int startBlock)
        throws IOException
    {
        if (_bat == null)
        {
            throw new IOException(
                "Improperly initialized list: no block allocation table provided");
        }
        return _bat.fetchBlocks(startBlock, this);
    }

    /**
     * set the associated BlockAllocationTable
     *
     * @param bat the associated BlockAllocationTable
     *
     * @exception IOException
     */

    public void setBAT(final BlockAllocationTableReader bat)
        throws IOException
    {
        if (_bat != null)
        {
            throw new IOException(
                "Attempt to replace existing BlockAllocationTable");
        }
        _bat = bat;
    }

    /* **********  END  implementation of BlockList ********** */
}   // end package-scope class BlockListImpl