    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} 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         * Constructs a new instance.
    053         */
    054        public ItemSkippedException() {
    055            // empty
    056        }
    057
    058    }
    059
    060    /**
    061     * Returns the content type passed by the browser or {@code null} if
    062     * not defined.
    063     *
    064     * @return The content type passed by the browser or {@code null} if
    065     *         not defined.
    066     */
    067    String getContentType();
    068
    069    /**
    070     * Returns the name of the field in the multipart form corresponding to
    071     * this file item.
    072     *
    073     * @return The name of the form field.
    074     */
    075    String getFieldName();
    076
    077    /**
    078     * Returns the original file name in the client's file system, as provided by
    079     * the browser (or other client software). In most cases, this will be the
    080     * base file name, without path information. However, some clients, such as
    081     * the Opera browser, do include path information.
    082     *
    083     * @return The original file name in the client's file system.
    084     */
    085    String getName();
    086
    087    /**
    088     * Determines whether or not a {@code FileItem} instance represents
    089     * a simple form field.
    090     *
    091     * @return {@code true} if the instance represents a simple form
    092     *         field; {@code false} if it represents an uploaded file.
    093     */
    094    boolean isFormField();
    095
    096    /**
    097     * Creates an {@link InputStream}, which allows to read the
    098     * items contents.
    099     *
    100     * @return The input stream, from which the items data may
    101     *   be read.
    102     * @throws IllegalStateException The method was already invoked on
    103     * this item. It is not possible to recreate the data stream.
    104     * @throws IOException An I/O error occurred.
    105     * @see ItemSkippedException
    106     */
    107    InputStream openStream() throws IOException;
    108
    109}