/*
 * Copyright 2004-2010 the Seasar Foundation and the Others.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package org.slim3.controller.upload;

import java.io.IOException;
import java.io.InputStream;

/**
 * This interface provides access to a file or form item that was received
 * within a <code>multipart/form-data</code> POST request.
 * 
 * @author higa
 * @since 1.0.0
 * 
 */
public interface FileItemStream {

    /**
     * Creates an {@link InputStream}, which allows to read the items contents.
     * 
     * @return The input stream, from which the items data may be read.
     * @throws IllegalStateException
     *             The method was already invoked on this item. It is not
     *             possible to recreate the data stream.
     * @throws IOException
     *             An I/O error occurred.
     */
    InputStream openStream() 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 getFileName();

    /**
     * Returns the name of the field in the multipart form corresponding to this
     * file item.
     * 
     * @return The name of the form field.
     */
    String getFieldName();

    /**
     * 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();
}