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https://issues.apache.org/jira/browse/IO-546?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16128181#comment-16128181
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Elijah Zupancic commented on IO-546:
------------------------------------
This sample application illustrates the inconsistency:
{code:java}
import org.apache.commons.io.IOUtils;
import org.apache.commons.io.output.CloseShieldOutputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
public class BrokenShield {
public static void main(String[] argv) throws IOException {
File file = File.createTempFile("broken-shield", "txt");
byte[] arbitraryData = "Hello World ".getBytes(StandardCharsets.UTF_8);
FileOutputStream fout = new FileOutputStream(file);
BufferedOutputStream bout = new BufferedOutputStream(fout, 99999);
CloseShieldOutputStream cout = new CloseShieldOutputStream(fout);
try {
// This should work because we haven't tried to close the stream
cout.write(arbitraryData);
// Here we pretend this is some stupid library that insists on
// closing a stream when it shouldn't.
cout.close();
// After we try to close the stream, new data can't be written to
// the stream. For example: cout.write(arbitraryData);
// Would throw an exception like:
// java.io.IOException: write(72) failed: stream is closed
// However, if we call flush(), no exception is thrown - this is
// inconsistent with the behavior of write()
cout.flush();
} finally {
// We properly close the stream we have to use the underlying
// stream like you would expect.
fout.close();
}
try (FileInputStream fin = new FileInputStream(file)) {
String data = IOUtils.toString(fin, StandardCharsets.UTF_8);
System.out.println(data);
}
}
}
{code}
> ClosedOutputStream#flush should throw
> -------------------------------------
>
> Key: IO-546
> URL: https://issues.apache.org/jira/browse/IO-546
> Project: Commons IO
> Issue Type: Improvement
> Components: Streams/Writers
> Reporter: Tomas Celaya
> Priority: Minor
> Attachments: IO-546.patch
>
>
> While debugging an issue involving usage of {{CloseShieldOutputStream}} I
> discovered that {{ClosedOutputStream#flush}} is not overridden and will
> silently succeed. Not sure how much of a breaking change this might be but I
> think it makes more sense for {{ClosedOutputStream#flush}} to throw. This is
> only really meaningful in contexts where multiple streams are being chained
> together and some of the streams before {{CloseShieldOutputStream}} perform
> buffering, but it would make behavior more consistent for these more complex
> use-cases.
> No patches are included because I'm interested in hearing what the opinion
> would be on this issue. I can provide a patch if this seems like desired
> behavior.
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