org.springframework.core.io.InputStreamResource Maven / Gradle / Ivy
/*
* Copyright 2002-2018 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;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
/**
* {@link Resource} implementation for a given {@link InputStream}.
* Should only be used if no other specific {@code Resource} implementation
* is applicable. In particular, prefer {@link ByteArrayResource} or any of the
* file-based {@code Resource} implementations where possible.
*
*
In contrast to other {@code Resource} implementations, this is a descriptor
* for an already opened resource - therefore returning {@code true} from
* {@link #isOpen()}. Do not use an {@code InputStreamResource} if you need to
* keep the resource descriptor somewhere, or if you need to read from a stream
* multiple times.
*
* @author Juergen Hoeller
* @author Sam Brannen
* @since 28.12.2003
* @see ByteArrayResource
* @see ClassPathResource
* @see FileSystemResource
* @see UrlResource
*/
public class InputStreamResource extends AbstractResource {
private final InputStream inputStream;
private final String description;
private boolean read = false;
/**
* Create a new InputStreamResource.
* @param inputStream the InputStream to use
*/
public InputStreamResource(InputStream inputStream) {
this(inputStream, "resource loaded through InputStream");
}
/**
* Create a new InputStreamResource.
* @param inputStream the InputStream to use
* @param description where the InputStream comes from
*/
public InputStreamResource(InputStream inputStream, @Nullable String description) {
Assert.notNull(inputStream, "InputStream must not be null");
this.inputStream = inputStream;
this.description = (description != null ? description : "");
}
/**
* This implementation always returns {@code true}.
*/
@Override
public boolean exists() {
return true;
}
/**
* This implementation always returns {@code true}.
*/
@Override
public boolean isOpen() {
return true;
}
/**
* This implementation throws IllegalStateException if attempting to
* read the underlying stream multiple times.
*/
@Override
public InputStream getInputStream() throws IOException, IllegalStateException {
if (this.read) {
throw new IllegalStateException("InputStream has already been read - " +
"do not use InputStreamResource if a stream needs to be read multiple times");
}
this.read = true;
return this.inputStream;
}
/**
* This implementation returns a description that includes the passed-in
* description, if any.
*/
@Override
public String getDescription() {
return "InputStream resource [" + this.description + "]";
}
/**
* This implementation compares the underlying InputStream.
*/
@Override
public boolean equals(Object other) {
return (this == other || (other instanceof InputStreamResource &&
((InputStreamResource) other).inputStream.equals(this.inputStream)));
}
/**
* This implementation returns the hash code of the underlying InputStream.
*/
@Override
public int hashCode() {
return this.inputStream.hashCode();
}
}