    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.fileupload;
    018
    019import java.io.IOException;
    020import java.io.InputStream;
    021
    022/**
    023 * <p> This interface provides access to a file or form item that was
    024 * received within a <code>multipart/form-data</code> POST request.
    025 * The items contents are retrieved by calling {@link #openStream()}.</p>
    026 * <p>Instances of this class are created by accessing the
    027 * iterator, returned by
    028 * {@link FileUploadBase#getItemIterator(RequestContext)}.</p>
    029 * <p><em>Note</em>: There is an interaction between the iterator and
    030 * its associated instances of {@link FileItemStream}: By invoking
    031 * {@link java.util.Iterator#hasNext()} on the iterator, you discard all data,
    032 * which hasn't been read so far from the previous data.</p>
    033 */
    034public interface FileItemStream extends FileItemHeadersSupport {
    035
    036    /**
    037     * This exception is thrown, if an attempt is made to read
    038     * data from the {@link InputStream}, which has been returned
    039     * by {@link FileItemStream#openStream()}, after
    040     * {@link java.util.Iterator#hasNext()} has been invoked on the
    041     * iterator, which created the {@link FileItemStream}.
    042     */
    043    class ItemSkippedException extends IOException {
    044
    045        /**
    046         * The exceptions serial version UID, which is being used
    047         * when serializing an exception instance.
    048         */
    049        private static final long serialVersionUID = -7280778431581963740L;
    050
    051    }
    052
    053    /**
    054     * Creates an {@link InputStream}, which allows to read the
    055     * items contents.
    056     *
    057     * @return The input stream, from which the items data may
    058     *   be read.
    059     * @throws IllegalStateException The method was already invoked on
    060     * this item. It is not possible to recreate the data stream.
    061     * @throws IOException An I/O error occurred.
    062     * @see ItemSkippedException
    063     */
    064    InputStream openStream() throws IOException;
    065
    066    /**
    067     * Returns the content type passed by the browser or <code>null</code> if
    068     * not defined.
    069     *
    070     * @return The content type passed by the browser or <code>null</code> if
    071     *         not defined.
    072     */
    073    String getContentType();
    074
    075    /**
    076     * Returns the original filename in the client's filesystem, as provided by
    077     * the browser (or other client software). In most cases, this will be the
    078     * base file name, without path information. However, some clients, such as
    079     * the Opera browser, do include path information.
    080     *
    081     * @return The original filename in the client's filesystem.
    082     */
    083    String getName();
    084
    085    /**
    086     * Returns the name of the field in the multipart form corresponding to
    087     * this file item.
    088     *
    089     * @return The name of the form field.
    090     */
    091    String getFieldName();
    092
    093    /**
    094     * Determines whether or not a <code>FileItem</code> instance represents
    095     * a simple form field.
    096     *
    097     * @return <code>true</code> if the instance represents a simple form
    098     *         field; <code>false</code> if it represents an uploaded file.
    099     */
    100    boolean isFormField();
    101
    102}