org.springframework.core.io.InputStreamSource Maven / Gradle / Ivy
/*
* Copyright 2002-2017 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
*
* https://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 an {@link InputStream}.
*
* This is the base interface for Spring's more extensive {@link Resource} interface.
*
*
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} for the content of an underlying resource.
*
It is expected that each call creates a fresh stream.
*
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 required
* that each {@code getInputStream()} call returns a fresh stream.
* @return the input stream for the underlying resource (must not be {@code null})
* @throws java.io.FileNotFoundException if the underlying resource doesn't exist
* @throws IOException if the content stream could not be opened
*/
InputStream getInputStream() throws IOException;
}