Re: BufferedWriter.write does not throw exception if it is already closed.

[Alan Bateman]

Jing LV wrote:
Thanks for reply Alan, sorry didn't see this mail before I raise an 
issue on https://bugs.openjdk.java.net/show_bug.cgi?id=100169 (my mail 
server seems some problem these days)

Consider it is using underlying writer, one thing I need to mention is 
that in the testcase I post in the first mail, it was trying to throw 
an exception[1] in its write method when it's closed already. I am ok 
with the documentation modification myself, however I wonder it may 
confuse customer if he found his own writer has no problem at all?

[1]
@Override
public void write(char[] buf, int offset, int count) throws
IOException {
    if (closed) {
        throw new IOException("Already closed");
    }
}
I'll add S=7015589 to that bugzilla bug so that it links to the links to 
the "Sun" bug that I created after the previous mail.

I don't think I fully understand what you are saying in the above but 
let me just repeat that I think we should look at clarifying close so 
that the BufferedWriter is considered closed even if the close method 
fails with an IOException. That would mean that a subsequence attempt to 
write to the closed stream (irrespective of whether close completed with 
or without an exception) would fail consistently rather than being 
dependent on the buffer size. See attached as an initial patch to see 
how it would work. I was just mentioning that we can fix a few other 
issues while we are there - for example the exception from the 
underlying writer's close supplants the exception from the flush.

-Alan


diff --git a/src/share/classes/java/io/BufferedReader.java 
b/src/share/classes/java/io/BufferedReader.java
--- a/src/share/classes/java/io/BufferedReader.java
+++ b/src/share/classes/java/io/BufferedReader.java
@@ -514,9 +514,12 @@ public class BufferedReader extends Read
        synchronized (lock) {
            if (in == null)
                return;
-            in.close();
-            in = null;
-            cb = null;
+            try {
+                in.close();
+            } finally {
+                in = null;
+                cb = null;
+            }
        }
    }
}
diff --git a/src/share/classes/java/io/BufferedWriter.java 
b/src/share/classes/java/io/BufferedWriter.java
--- a/src/share/classes/java/io/BufferedWriter.java
+++ b/src/share/classes/java/io/BufferedWriter.java
@@ -260,10 +260,9 @@ public class BufferedWriter extends Writ
            if (out == null) {
                return;
            }
-            try {
+            try (Writer w = out) {
                flushBuffer();
            } finally {
-                out.close();
                out = null;
                cb = null;
            }
diff --git a/src/share/classes/java/io/FilterOutputStream.java 
b/src/share/classes/java/io/FilterOutputStream.java
--- a/src/share/classes/java/io/FilterOutputStream.java
+++ b/src/share/classes/java/io/FilterOutputStream.java
@@ -153,10 +153,8 @@ class FilterOutputStream extends OutputS
     * @see        java.io.FilterOutputStream#out
     */
    public void close() throws IOException {
-        try {
-          flush();
-        } catch (IOException ignored) {
+        try (OutputStream ostream = out) {
+            flush();
        }
-        out.close();
    }
}