poifsviewable.java

Office格式转换代码

/* ====================================================================
 * 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",
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 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * ====================================================================
 *
 * 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.dev;

import java.util.Iterator;

/**
 * Interface for a drill-down viewable object. Such an object has
 * content that may or may not be displayed, at the discretion of the
 * viewer. The content is returned to the viewer as an array or as an
 * Iterator, and the object provides a clue as to which technique the
 * viewer should use to get its content.
 *
 * A POIFSViewable object is also expected to provide a short
 * description of itself, that can be used by a viewer when the
 * viewable object is collapsed.
 *
 * @author Marc Johnson (mjohnson at apache dot org)
 */

public interface POIFSViewable
{

    /**
     * Get an array of objects, some of which may implement
     * POIFSViewable
     *
     * @return an array of Object; may not be null, but may be empty
     */

    public Object [] getViewableArray();

    /**
     * Get an Iterator of objects, some of which may implement
     * POIFSViewable
     *
     * @return an Iterator; may not be null, but may have an empty
     * back end store
     */

    public Iterator getViewableIterator();

    /**
     * Give viewers a hint as to whether to call getViewableArray or
     * getViewableIterator
     *
     * @return true if a viewer should call getViewableArray, false if
     *         a viewer should call getViewableIterator
     */

    public boolean preferArray();

    /**
     * Provides a short description of the object, to be used when a
     * POIFSViewable object has not provided its contents.
     *
     * @return short description
     */

    public String getShortDescription();
}   // end public interface POIFSViewable