inputstreamsource.java

spring的源代码

/*
 * Copyright 2002-2005 the original author or authors.
 * 
 * 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.springframework.core.io;

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

/**
 * Simple interface for objects that are sources for a <code>java.io.InputStream</code>.
 * Base interface for Spring's more extensive Resource interface.
 *
 * <p>Useful as an abstract content source for mail attachments, for example.
 * Spring's ByteArrayResource or any file-based Resource implementation can be used
 * as concrete instance, allowing to read the underlying content stream multiple times.
 * For single-use streams, InputStreamResource can be used for any given InputStream.
 *
 * @author Juergen Hoeller
 * @since 20.01.2004
 * @see java.io.InputStream
 * @see Resource
 * @see InputStreamResource
 * @see ByteArrayResource
 */
public interface InputStreamSource {

	/**
	 * Return an InputStream.
	 * It is expected that each call creates a <i>fresh</i> stream.
	 * <p>For creating mail attachments, note that JavaMail needs to be able to
	 * read the stream multiple times. For such a use case, it is <i>required</i>
	 * that each <code>getInputStream()</code> call returns a fresh stream.
	 * @throws IOException if the stream could not be opened
	 * @see org.springframework.mail.javamail.MimeMessageHelper#addAttachment(String, InputStreamSource)
	 */
	InputStream getInputStream() throws IOException;

}