/*
* Copyright 2002-2006 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;
/**
* {@link Resource} implementation for a given InputStream. Should only
* be used if no specific Resource implementation is applicable.
* In particular, prefer {@link ByteArrayResource} or any of the
* file-based Resource implementations where possible.
*
* <p>In contrast to other Resource implementations, this is a descriptor
* for an <i>already opened</i> resource - therefore returning "true" from
* <code>isOpen()</code>. Do not use it if you need to keep the resource
* descriptor somewhere, or if you need to read a stream multiple times.
*
* @author Juergen Hoeller
* @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, String description) {
if (inputStream == null) {
throw new IllegalArgumentException("InputStream must not be null");
}
this.inputStream = inputStream;
this.description = (description != null ? description : "");
}
/**
* This implementation always returns <code>true</code>.
*/
@Override
public boolean exists() {
return true;
}
/**
* This implementation always returns <code>true</code>.
*/
@Override
public boolean isOpen() {
return true;
}
/**
* This implementation throws IllegalStateException if attempting to
* read the underlying stream multiple times.
*/
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 the passed-in description, if any.
*/
public String getDescription() {
return this.description;
}
/**
* This implementation compares the underlying InputStream.
*/
@Override
public boolean equals(Object obj) {
return (obj == this ||
(obj instanceof InputStreamResource && ((InputStreamResource) obj).inputStream.equals(this.inputStream)));
}
/**
* This implementation returns the hash code of the underlying InputStream.
*/
@Override
public int hashCode() {
return this.inputStream.hashCode();
}
}
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