Sounds reasonable to me. I'll commit this if no one objects.
Jake
At 12:27 AM 11/17/2003 +0100, you wrote:
Hi,
While investigating the speed of an application that uses XMLC 2.2.3, I
encountered a serious performance bug in DOMFormatter. The DOMFormatter
is used to write out the HTML (or XML) representation of a DOM tree. It
uses a Writer onto a buffered output stream, but the Writer is itself not
wrapped in a BufferedWriter. Without the BufferedWriter, every invocation
of one of the Writer's write() methods causes the allocation of one
object, presumably a byte array. Invoking the single-character-write
method is one object worse, presumably it requires a character
array. This includes the frequent invocations to the write methods to
emit a '<', '&', and '>' characters.
I didn't perform any serious measurements targeting this particular memory
consumer. I can relate that this fix was part of an effort to reduce
memory consumption of a page that allocated approximately 260000 objects
to display. After some playing with a profiler, the memory consumption
was reduced by 50%, a significant part of which comes from this XMLC
fix. Find the diff attached below. I'm interested to hear about the real
performance-gain figures.
Regards,
Pieter Schoenmakers
diff -r -u
xmlc-src-2.2.3-/xmlc/modules/xmlc/src/org/enhydra/xml/io/DOMFormatter.java
xmlc-src-2.2.3/xmlc/modules/xmlc/src/org/enhydra/xml/io/DOMFormatter.java
---
xmlc-src-2.2.3-/xmlc/modules/xmlc/src/org/enhydra/xml/io/DOMFormatter.java
2003-03-10 10:36:16.000000000 +0100
+++
xmlc-src-2.2.3/xmlc/modules/xmlc/src/org/enhydra/xml/io/DOMFormatter.java
2003-11-13 12:05:37.000000000 +0100
@@ -26,6 +26,7 @@
import org.enhydra.xml.dom.DOMOps;
import org.enhydra.xml.dom.DOMAccess;
import java.io.Writer;
+import java.io.BufferedWriter;
import java.io.StringWriter;
import java.io.ByteArrayOutputStream;
import java.io.OutputStreamWriter;
@@ -199,8 +200,8 @@
public void write(Node node,
OutputStream out) throws IOException {
Formatter formatter = getFormatter(node, fOptions, false);
- Writer writer = new OutputStreamWriter(out,
- formatter.getMIMEEncoding());
+ Writer writer = new BufferedWriter (new OutputStreamWriter(out,
+ formatter.getMIMEEncoding()));
formatter.write(node, writer);
writer.flush();
}
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