You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@openjpa.apache.org by jg...@apache.org on 2011/09/26 22:25:44 UTC

svn commit: r1176024 - in /openjpa/branches/1.2.x: openjpa-kernel/src/main/java/org/apache/openjpa/conf/ openjpa-lib/src/main/java/org/apache/openjpa/lib/meta/ openjpa-lib/src/main/java/org/apache/openjpa/lib/util/ openjpa-lib/src/main/resources/org/ap...

Author: jgrassel
Date: Mon Sep 26 20:25:44 2011
New Revision: 1176024

URL: http://svn.apache.org/viewvc?rev=1176024&view=rev
Log:
OPENJPA-1993: Deadlock Potential with ORM XML Processing

Modified:
    openjpa/branches/1.2.x/openjpa-kernel/src/main/java/org/apache/openjpa/conf/Compatibility.java
    openjpa/branches/1.2.x/openjpa-lib/src/main/java/org/apache/openjpa/lib/meta/XMLMetaDataParser.java
    openjpa/branches/1.2.x/openjpa-lib/src/main/java/org/apache/openjpa/lib/util/J2DoPrivHelper.java
    openjpa/branches/1.2.x/openjpa-lib/src/main/resources/org/apache/openjpa/lib/meta/localizer.properties
    openjpa/branches/1.2.x/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/XMLPersistenceMetaDataParser.java

Modified: openjpa/branches/1.2.x/openjpa-kernel/src/main/java/org/apache/openjpa/conf/Compatibility.java
URL: http://svn.apache.org/viewvc/openjpa/branches/1.2.x/openjpa-kernel/src/main/java/org/apache/openjpa/conf/Compatibility.java?rev=1176024&r1=1176023&r2=1176024&view=diff
==============================================================================
--- openjpa/branches/1.2.x/openjpa-kernel/src/main/java/org/apache/openjpa/conf/Compatibility.java (original)
+++ openjpa/branches/1.2.x/openjpa-kernel/src/main/java/org/apache/openjpa/conf/Compatibility.java Mon Sep 26 20:25:44 2011
@@ -58,6 +58,7 @@ public class Compatibility {
     private boolean _flushBeforeDetach = true;
     private boolean _reorderMetaDataResolution = false;
     private boolean _reloadOnDetach = true;
+    private boolean _overrideContextClassloader = false;
 
     /**
      * Whether to require exact identity value types when creating object
@@ -318,6 +319,23 @@ public class Compatibility {
         _reloadOnDetach = reloadOnDetach;
     }   
 
+    /**
+     * Whether to temporally override the thread's Context Classloader when processing
+     * ORM XML documents to avoid deadlock potential with certain Classloader hierarchy
+     * configurations.  Defaults to false.
+     */
+    public boolean getOverrideContextClassloader() {
+        return _overrideContextClassloader;
+    }
+
+    /**
+     * Whether to temporally override the thread's Context Classloader when processing
+     * ORM XML documents to avoid deadlock potential with certain Classloader hierarchy
+     * configurations.  Defaults to false.
+     */
+    public void setOverrideContextClassloader(boolean overrideContextClassloader) {
+        _overrideContextClassloader = overrideContextClassloader;
+    }
     
 
 }

Modified: openjpa/branches/1.2.x/openjpa-lib/src/main/java/org/apache/openjpa/lib/meta/XMLMetaDataParser.java
URL: http://svn.apache.org/viewvc/openjpa/branches/1.2.x/openjpa-lib/src/main/java/org/apache/openjpa/lib/meta/XMLMetaDataParser.java?rev=1176024&r1=1176023&r2=1176024&view=diff
==============================================================================
--- openjpa/branches/1.2.x/openjpa-lib/src/main/java/org/apache/openjpa/lib/meta/XMLMetaDataParser.java (original)
+++ openjpa/branches/1.2.x/openjpa-lib/src/main/java/org/apache/openjpa/lib/meta/XMLMetaDataParser.java Mon Sep 26 20:25:44 2011
@@ -105,7 +105,17 @@ public abstract class XMLMetaDataParser 
     private LexicalHandler _lh = null;
     private int _depth = -1;
     private int _ignore = Integer.MAX_VALUE;
+    
+    private boolean _overrideContextClassloader = false;
 
+    public boolean getOverrideContextClassloader() {
+        return _overrideContextClassloader;
+    }
+    
+    public void setOverrideContextClassloader(boolean overrideCCL) {
+        _overrideContextClassloader = overrideCCL;
+    }
+    
     /**
      * Whether to parse element text.
      */
@@ -349,36 +359,68 @@ public abstract class XMLMetaDataParser 
         // parse the metadata with a SAX parser
         try {
             _sourceName = sourceName;
-            SAXParser parser = XMLFactory.getSAXParser(validating, true);
-            Object schema = null;
-            if (validating) {
-                schema = schemaSource;
-                if (schema == null && getDocType() != null)
-                    xml = new DocTypeReader(xml, getDocType());
-            }
+            SAXParser parser = null;
+            boolean overrideCL = _overrideContextClassloader;
+            ClassLoader oldLoader = null;
+            ClassLoader newLoader = null; 
+            
+            try {
+                if (overrideCL == true) {
+                    oldLoader = (ClassLoader) AccessController.doPrivileged(
+                        J2DoPrivHelper.getContextClassLoaderAction());
+                    newLoader = XMLMetaDataParser.class.getClassLoader();
+                    AccessController.doPrivileged(J2DoPrivHelper.setContextClassLoaderAction(newLoader));
+                    
+                    if (_log != null && _log.isTraceEnabled()) {
+                        _log.trace(_loc.get("override-contextclassloader-begin", oldLoader, newLoader));
+                    } 
+                }
+                
+                parser = XMLFactory.getSAXParser(validating, true);
+                Object schema = null;
+                if (validating) {
+                    schema = schemaSource;
+                    if (schema == null && getDocType() != null)
+                        xml = new DocTypeReader(xml, getDocType());
+                }
 
-            if (_parseComments || _lh != null)
-                parser.setProperty
-                    ("http://xml.org/sax/properties/lexical-handler", this);
-
-            if (schema != null) {
-                parser.setProperty
-                    ("http://java.sun.com/xml/jaxp/properties/schemaLanguage",
-                        "http://www.w3.org/2001/XMLSchema");
-                parser.setProperty
-                    ("http://java.sun.com/xml/jaxp/properties/schemaSource",
-                        schema);
-            }
+                if (_parseComments || _lh != null)
+                    parser.setProperty
+                        ("http://xml.org/sax/properties/lexical-handler", this);
+
+                if (schema != null) {
+                    parser.setProperty
+                        ("http://java.sun.com/xml/jaxp/properties/schemaLanguage",
+                            "http://www.w3.org/2001/XMLSchema");
+                    parser.setProperty
+                        ("http://java.sun.com/xml/jaxp/properties/schemaSource",
+                            schema);
+                }
 
-            InputSource is = new InputSource(xml);
-            if (_systemId && sourceName != null)
-                is.setSystemId(sourceName);
-            parser.parse(is, this);
-            finish();
-        } catch (SAXException se) {
-            IOException ioe = new IOException(se.toString());
-            JavaVersions.initCause(ioe, se);
-            throw ioe;
+                InputSource is = new InputSource(xml);
+                if (_systemId && sourceName != null)
+                    is.setSystemId(sourceName);
+                parser.parse(is, this);
+                finish();
+            } catch (SAXException se) {
+                IOException ioe = new IOException(se.toString());
+                JavaVersions.initCause(ioe, se);
+                throw ioe;
+            } finally {
+                if (overrideCL == true) {
+                    // Restore the old ContextClassloader
+                    try {
+                        if (_log != null && _log.isTraceEnabled()) {
+                            _log.trace(_loc.get("override-contextclassloader-end", newLoader, oldLoader));
+                        }
+                        AccessController.doPrivileged(J2DoPrivHelper.setContextClassLoaderAction(oldLoader));
+                    } catch (Throwable t) {
+                        if (_log != null && _log.isWarnEnabled()) {
+                            _log.warn(_loc.get("restore-contextclassloader-failed"));
+                        }
+                    }
+                }
+            }
         } finally {
             reset();
         }

Modified: openjpa/branches/1.2.x/openjpa-lib/src/main/java/org/apache/openjpa/lib/util/J2DoPrivHelper.java
URL: http://svn.apache.org/viewvc/openjpa/branches/1.2.x/openjpa-lib/src/main/java/org/apache/openjpa/lib/util/J2DoPrivHelper.java?rev=1176024&r1=1176023&r2=1176024&view=diff
==============================================================================
--- openjpa/branches/1.2.x/openjpa-lib/src/main/java/org/apache/openjpa/lib/util/J2DoPrivHelper.java (original)
+++ openjpa/branches/1.2.x/openjpa-lib/src/main/java/org/apache/openjpa/lib/util/J2DoPrivHelper.java Mon Sep 26 20:25:44 2011
@@ -789,6 +789,25 @@ public abstract class J2DoPrivHelper {
             }
         };
     }
+    
+    /**
+     * Return a PrivilegeAction object for Thread.currentThread
+     *   .setContextClassLoader().
+     * 
+     * Requires security policy:
+     *   'permission java.lang.RuntimePermission "setContextClassLoader";'
+     *   
+     * @return ClassLoader
+     */
+    public static final PrivilegedAction<Boolean> 
+            setContextClassLoaderAction(final ClassLoader loader) {
+        return new PrivilegedAction<Boolean>() {
+            public Boolean run() {
+                Thread.currentThread().setContextClassLoader(loader);
+                return Boolean.TRUE;
+            }
+        };
+    }
 
     /**
      * Return a PrivilegedAction object for new Thread().

Modified: openjpa/branches/1.2.x/openjpa-lib/src/main/resources/org/apache/openjpa/lib/meta/localizer.properties
URL: http://svn.apache.org/viewvc/openjpa/branches/1.2.x/openjpa-lib/src/main/resources/org/apache/openjpa/lib/meta/localizer.properties?rev=1176024&r1=1176023&r2=1176024&view=diff
==============================================================================
--- openjpa/branches/1.2.x/openjpa-lib/src/main/resources/org/apache/openjpa/lib/meta/localizer.properties (original)
+++ openjpa/branches/1.2.x/openjpa-lib/src/main/resources/org/apache/openjpa/lib/meta/localizer.properties Mon Sep 26 20:25:44 2011
@@ -25,6 +25,12 @@ cant-diff-elems: Unable to differentiate
 	elements for class arg parsing.  No element can be a complete prefix of \
 	another.
 class-arg: Error extracting class information from "{0}".
+override-contextclassloader-begin: Overriding thread context classloader \
+    from "{0}" to "{1}".
+override-contextclassloader-end: Restoring thread context classloader \
+    from "{0}" to "{1}".
+restore-contextclassloader-failed: An error occurred restoring the Thread's \
+    context classloader.
 parse-error: An error was encountered while parsing element "{0}".  Make sure \
 	the metadata file is correctly formatted.
 no-file: No source file found for "{0}".

Modified: openjpa/branches/1.2.x/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/XMLPersistenceMetaDataParser.java
URL: http://svn.apache.org/viewvc/openjpa/branches/1.2.x/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/XMLPersistenceMetaDataParser.java?rev=1176024&r1=1176023&r2=1176024&view=diff
==============================================================================
--- openjpa/branches/1.2.x/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/XMLPersistenceMetaDataParser.java (original)
+++ openjpa/branches/1.2.x/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/XMLPersistenceMetaDataParser.java Mon Sep 26 20:25:44 2011
@@ -238,6 +238,14 @@ public class XMLPersistenceMetaDataParse
         if (repos != null
             && (repos.getValidate() & repos.VALIDATE_RUNTIME) != 0)
             setParseComments(false);
+        
+        if (repos != null) {
+            // Determine if the Thread Context Classloader needs to be temporally overridden to the Classloader
+            // that loaded the OpenJPA classes, to avoid a potential deadlock issue with the way Xerces
+            // handles parsers and classloaders.
+            this.setOverrideContextClassloader(repos.getConfiguration().getCompatibilityInstance().
+                getOverrideContextClassloader());
+        }
     }
 
     /**