Java tutorial
/* * $Header: /home/cvs/jakarta-commons/fileupload/src/java/org/apache/commons/fileupload/FileItem.java,v 1.15 2003/06/01 17:33:24 martinc Exp $ * $Revision: 1.15 $ * $Date: 2003/06/01 17:33:24 $ * * ==================================================================== * * The Apache Software License, Version 1.1 * * Copyright (c) 2001-2003 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 acknowlegement: * "This product includes software developed by the * Apache Software Foundation (http://www.apache.org/)." * Alternately, this acknowlegement may appear in the software itself, * if and wherever such third-party acknowlegements normally appear. * * 4. The names "The Jakarta Project", "Commons", and "Apache Software * Foundation" must not be used to endorse or promote products derived * from this software without prior written permission. For written * permission, please contact apache@apache.org. * * 5. Products derived from this software may not be called "Apache" * nor may "Apache" appear in their names without prior written * permission of the Apache Group. * * 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 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * 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.commons.fileupload; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.Serializable; import java.io.UnsupportedEncodingException; /** * <p> This class represents a file or form item that was received within a * <code>multipart/form-data</code> POST request. * * <p> After retrieving an instance of this class from a {@link * org.apache.commons.fileupload.FileUpload FileUpload} instance (see * {@link org.apache.commons.fileupload.FileUpload * #parseRequest(javax.servlet.http.HttpServletRequest)}), you may * either request all contents of the file at once using {@link #get()} or * request an {@link java.io.InputStream InputStream} with * {@link #getInputStream()} and process the file without attempting to load * it into memory, which may come handy with large files. * * <p> While this interface does not extend * <code>javax.activation.DataSource</code> per se (to avoid a seldom used * dependency), several of the defined methods are specifically defined with * the same signatures as methods in that interface. This allows an * implementation of this interface to also implement * <code>javax.activation.DataSource</code> with minimal additional work. * * @author <a href="mailto:Rafal.Krzewski@e-point.pl">Rafal Krzewski</a> * @author <a href="mailto:sean@informage.net">Sean Legassick</a> * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a> * @author <a href="mailto:martinc@apache.org">Martin Cooper</a> * * @version $Id: FileItem.java,v 1.15 2003/06/01 17:33:24 martinc Exp $ */ public interface FileItem extends Serializable { // ------------------------------- Methods from javax.activation.DataSource /** * Returns an {@link java.io.InputStream InputStream} that can be * used to retrieve the contents of the file. * * @return An {@link java.io.InputStream InputStream} that can be * used to retrieve the contents of the file. * * @exception IOException if an error occurs. */ InputStream getInputStream() throws IOException; /** * Returns the content type passed by the browser or <code>null</code> if * not defined. * * @return The content type passed by the browser or <code>null</code> if * not defined. */ String getContentType(); /** * Returns the original filename in the client's filesystem, as provided by * the browser (or other client software). In most cases, this will be the * base file name, without path information. However, some clients, such as * the Opera browser, do include path information. * * @return The original filename in the client's filesystem. */ String getName(); // ------------------------------------------------------- FileItem methods /** * Provides a hint as to whether or not the file contents will be read * from memory. * * @return <code>true</code> if the file contents will be read from memory; * <code>false</code> otherwise. */ boolean isInMemory(); /** * Returns the size of the file item. * * @return The size of the file item, in bytes. */ long getSize(); /** * Returns the contents of the file item as an array of bytes. * * @return The contents of the file item as an array of bytes. */ byte[] get(); /** * Returns the contents of the file item as a String, using the specified * encoding. This method uses {@link #get()} to retrieve the * contents of the item. * * @param encoding The character encoding to use. * * @return The contents of the item, as a string. * * @exception UnsupportedEncodingException if the requested character * encoding is not available. */ String getString(String encoding) throws UnsupportedEncodingException; /** * Returns the contents of the file item as a String, using the default * character encoding. This method uses {@link #get()} to retrieve the * contents of the item. * * @return The contents of the item, as a string. */ String getString(); /** * A convenience method to write an uploaded item to disk. The client code * is not concerned with whether or not the item is stored in memory, or on * disk in a temporary location. They just want to write the uploaded item * to a file. * <p> * This method is not guaranteed to succeed if called more than once for * the same item. This allows a particular implementation to use, for * example, file renaming, where possible, rather than copying all of the * underlying data, thus gaining a significant performance benefit. * * @param file The <code>File</code> into which the uploaded item should * be stored. * * @exception Exception if an error occurs. */ void write(File file) throws Exception; /** * Deletes the underlying storage for a file item, including deleting any * associated temporary disk file. Although this storage will be deleted * automatically when the <code>FileItem</code> instance is garbage * collected, this method can be used to ensure that this is done at an * earlier time, thus preserving system resources. */ void delete(); /** * Returns the name of the field in the multipart form corresponding to * this file item. * * @return The name of the form field. */ String getFieldName(); /** * Sets the field name used to reference this file item. * * @param name The name of the form field. */ void setFieldName(String name); /** * Determines whether or not a <code>FileItem</code> instance represents * a simple form field. * * @return <code>true</code> if the instance represents a simple form * field; <code>false</code> if it represents an uploaded file. */ boolean isFormField(); /** * Specifies whether or not a <code>FileItem</code> instance represents * a simple form field. * * @param state <code>true</code> if the instance represents a simple form * field; <code>false</code> if it represents an uploaded file. */ void setFormField(boolean state); /** * Returns an {@link java.io.OutputStream OutputStream} that can * be used for storing the contents of the file. * * @return An {@link java.io.OutputStream OutputStream} that can be used * for storing the contensts of the file. * * @exception IOException if an error occurs. */ OutputStream getOutputStream() throws IOException; }