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https://issues.apache.org/jira/browse/GEODE-3306?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16137042#comment-16137042
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ASF subversion and git services commented on GEODE-3306:
--------------------------------------------------------
Commit f2891791bf8b84856ef398b63829913439c5c123 in geode's branch
refs/heads/develop from [~darrenfoong]
[ https://git-wip-us.apache.org/repos/asf?p=geode.git;h=f289179 ]
GEODE-3306: Remove whitespace StringBuffers/nodes created by Apache Xerces
This commit makes Geode compatible with the official Apache Xerces
implementation, which calls `characters()` when it reads ignorable
whitespace in `cache.xml`.
The while loop is required to handle comments in `cache.xml`, i.e.
a comment with whitespace before and after will generate two
empty StringBuffers (one for each set of whitespace before and after)
on the parse stack. The while loop removes all "consecutive" whitespace
StringBuffers from the top of the stack.
(This closes #668.)
> Parsing of cache.xml with whitespace fails with Apache Xerces
> -------------------------------------------------------------
>
> Key: GEODE-3306
> URL: https://issues.apache.org/jira/browse/GEODE-3306
> Project: Geode
> Issue Type: Bug
> Components: management
> Affects Versions: 1.2.0
> Reporter: Darren Foong
> Priority: Minor
> Fix For: 1.2.0
>
>
> I am using Geode 1.2.0 and Apache Xerces 2.11.0 (not the one included in the
> Oracle JDK), and I encountered the following error when I tried to
> programmatically start a cache:
> {noformat}
> org.apache.geode.InternalGemFireError: Did not expected a
> java.lang.StringBuffer on top of the stack.
> Exception in thread "main" org.apache.geode.InternalGemFireError: Did not
> expected a java.lang.StringBuffer on top of the stack.
> at org.apache.geode.internal.Assert.throwError(Assert.java:94)
> at org.apache.geode.internal.Assert.assertTrue(Assert.java:117)
> at
> org.apache.geode.internal.cache.xmlcache.CacheXmlParser.endRegionAttributes(CacheXmlParser.java:1257)
> at
> org.apache.geode.internal.cache.xmlcache.CacheXmlParser.endElement(CacheXmlParser.java:2909)
> at
> org.apache.geode.internal.cache.xmlcache.CacheXmlParser$DefaultHandlerDelegate.endElement(CacheXmlParser.java:3374)
> at org.apache.xerces.parsers.AbstractSAXParser.endElement(Unknown
> Source)
> at
> org.apache.xerces.parsers.AbstractXMLDocumentParser.emptyElement(Unknown
> Source)
> at org.apache.xerces.impl.xs.XMLSchemaValidator.emptyElement(Unknown
> Source)
> at
> org.apache.xerces.impl.XMLNSDocumentScannerImpl.scanStartElement(Unknown
> Source)
> at
> org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown
> Source)
> at
> org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown
> Source)
> at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
> at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
> at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
> at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
> at org.apache.xerces.jaxp.SAXParserImpl$JAXPSAXParser.parse(Unknown
> Source)
> at org.apache.xerces.jaxp.SAXParserImpl.parse(Unknown Source)
> at javax.xml.parsers.SAXParser.parse(SAXParser.java:195)
> at
> org.apache.geode.internal.cache.xmlcache.CacheXmlParser.parse(CacheXmlParser.java:224)
> at
> org.apache.geode.internal.cache.GemFireCacheImpl.loadCacheXml(GemFireCacheImpl.java:4287)
> at
> org.apache.geode.internal.cache.GemFireCacheImpl.initializeDeclarativeCache(GemFireCacheImpl.java:1390)
> at
> org.apache.geode.internal.cache.GemFireCacheImpl.initialize(GemFireCacheImpl.java:1195)
> at
> org.apache.geode.internal.cache.GemFireCacheImpl.basicCreate(GemFireCacheImpl.java:758)
> at
> org.apache.geode.internal.cache.GemFireCacheImpl.create(GemFireCacheImpl.java:745)
> at org.apache.geode.cache.CacheFactory.create(CacheFactory.java:173)
> at org.apache.geode.cache.CacheFactory.create(CacheFactory.java:212)
> at server.ServerWhitespace.main(ServerWhitespace.java:8)
> {noformat}
> However, this does not happen when I don't use Apache Xerces, i.e. I rely on
> the version in the Oracle JDK (1.8).
> After getting the Geode source code and stepping through the parsing using
> the Eclipse debugger, I realised that there were unexpected StringBuffers
> pushed onto the parse stack, thus causing the problem.
> These StringBuffers were created and pushed by the {{characters()}} method
> (https://github.com/apache/geode/blob/develop/geode-core/src/main/java/org/apache/geode/internal/cache/xmlcache/CacheXmlParser.java#L3270).
> Changing the log level to {{TRACE}} and examining the parse stack showed
> that these StringBuffers contained the whitespace (including newlines)
> between the XML tags in {{cache.xml}}.
> When using the Oracle JDK's version of Xerces, these StringBuffers did not
> appear on the parse stack despite the whitespace.
> I have a proof of concept on GitHub:
> https://github.com/darrenfoong/geode-parser-poc The {{cache.xml}} file
> without whitespace between the tags was parsed without errors by both
> versions of Xerces.
> It could be the case that the JDK Xerces strips out whitespace while Apache
> Xerces doesn't; but this could be implemented in {{characters()}} by only
> pushing non-whitespace char arrays in the {{else}} block. However, there
> could be other XML parsing edge cases that I am unaware of.
> There should be others who need Apache Xerces for their projects; a fix would
> be appreciated.
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