/*
* Copyright 2002-2012 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.hotswap.agent.util.spring.io.resource;
import java.io.IOException;
import java.io.InputStream;
/**
* Simple interface for objects that are sources for an {@link InputStream}.
*
* <p>
* This is the base interface for Spring's more extensive {@link Resource}
* interface.
*
* <p>
* For single-use streams, {@link InputStreamResource} can be used for any given
* {@code InputStream}. Spring's {@link ByteArrayResource} or any file-based
* {@code Resource} implementation can be used as a concrete instance, allowing
* one to read the underlying content stream multiple times. This makes this
* interface useful as an abstract content source for mail attachments, for
* example.
*
* @author Juergen Hoeller
* @since 20.01.2004
* @see java.io.InputStream
* @see Resource
* @see InputStreamResource
* @see ByteArrayResource
*/
public interface InputStreamSource {
/**
* Return an {@link InputStream}.
* <p>
* It is expected that each call creates a <i>fresh</i> stream.
* <p>
* This requirement is particularly important when you consider an API such
* as JavaMail, which needs to be able to read the stream multiple times
* when creating mail attachments. For such a use case, it is
* <i>required</i> that each {@code getInputStream()} call returns a fresh
* stream.
*
* @return the input stream for the underlying resource (must not be
* {@code null})
* @throws IOException
* if the stream could not be opened
* @see org.springframework.mail.javamail.MimeMessageHelper#addAttachment(String,
* InputStreamSource)
*/
InputStream getInputStream() throws IOException;
}