Barnabas Bodnar created CXF-8125:
------------------------------------
Summary: Support for using thread-safe application-defined
StAX-factories
Key: CXF-8125
URL: https://issues.apache.org/jira/browse/CXF-8125
Project: CXF
Issue Type: Improvement
Components: Core
Affects Versions: 3.3.3
Reporter: Barnabas Bodnar
CXF assumes, application-defined (contextual property of the message)
StAX-factories are _not_ thread-safe and synchronizes accesses to them (eg. in
_org.apache.cxf.interceptor.StaxInInterceptor_):
{noformat}
XMLInputFactory factory = getXMLInputFactory(message);
if (factory == null) {
if (reader != null) {
xreader = StaxUtils.createXMLStreamReader(reader);
} else {
xreader = StaxUtils.createXMLStreamReader(is, encoding);
}
} else {
synchronized (factory) {
if (reader != null) {
xreader = factory.createXMLStreamReader(reader);
} else {
xreader = factory.createXMLStreamReader(is, encoding);
}
}{noformat}
This is basically correct, because the StAX-spec doesn't require a
_XMLInputFactory_ or a _XMLOutputFactory_ to be thread-safe.
However, this becomes problematic right with CXF's preferred
StAX-implementation, WSTX, because it *performs I/O (reads a few bytes)* in
_createXMLStreamReader()_:
{noformat}
at java.io.FilterInputStream.read(FilterInputStream.java:133)
at com.ctc.wstx.io.BaseReader.readBytes(BaseReader.java:155)
at com.ctc.wstx.io.UTF8Reader.loadMore(UTF8Reader.java:369)
at com.ctc.wstx.io.UTF8Reader.read(UTF8Reader.java:112)
at
com.ctc.wstx.io.ReaderBootstrapper.initialLoad(ReaderBootstrapper.java:254)
at
com.ctc.wstx.io.ReaderBootstrapper.bootstrapInput(ReaderBootstrapper.java:134)
at com.ctc.wstx.stax.WstxInputFactory.doCreateSR(WstxInputFactory.java:573)
at com.ctc.wstx.stax.WstxInputFactory.createSR(WstxInputFactory.java:633)
at com.ctc.wstx.stax.WstxInputFactory.createSR(WstxInputFactory.java:657)
at
com.ctc.wstx.stax.WstxInputFactory.createXMLStreamReader(WstxInputFactory.java:342)
at
org.apache.cxf.interceptor.StaxInInterceptor.handleMessage(StaxInInterceptor.java:134)
- locked <0x00000006f7ceef50> (a com.ctc.wstx.stax.WstxInputFactory)
{noformat}
If this synchronous read-operation blocks due to network issues, *all other
incoming SOAP-requests are blocked*:
{noformat}
java.lang.Thread.State: BLOCKED (on object monitor)
at
org.apache.cxf.interceptor.StaxInInterceptor.handleMessage(StaxInInterceptor.java:130)
- waiting to lock <0x00000006f7ceef50> (a
com.ctc.wstx.stax.WstxInputFactory)
at
org.apache.cxf.phase.PhaseInterceptorChain.doIntercept(PhaseInterceptorChain.java:308)
- locked <0x0000000781907170> (a org.apache.cxf.phase.PhaseInterceptorChain)
at
org.apache.cxf.transport.ChainInitiationObserver.onMessage(ChainInitiationObserver.java:121)
at
org.apache.cxf.transport.http.AbstractHTTPDestination.invoke(AbstractHTTPDestination.java:267)
at
org.apache.cxf.transport.servlet.ServletController.invokeDestination(ServletController.java:234)
{noformat}
Even if performing I/O here is a questionable behavior of WSTX, unneeded
synchronization should anyway be avoided for performance reasons. My proposal
is to introduce a boolean contextual property indicating whether the provided
factories are thread-safe and omit the synchronization, if set to _true_.
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