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SF1603631:

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concurrent modification of ROT (adding or removing thread tables) causes VM crash.  The simple fix is to sychronize all accessors to the ROT.  Performance impact has not been analyzed
This commit is contained in:
clay_shooter
2006-12-08 12:42:37 +00:00
parent 5ac71b76b4
commit 3b524074a6
1 changed files with 184 additions and 180 deletions
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106
src/com/jacob/com/ROT.java
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@@ -45,7 +45,7 @@ public abstract class ROT {
* Manual garbage collection was the only option pre 1.9
*/
protected static final boolean USE_AUTOMATIC_GARBAGE_COLLECTION =
"true".equalsIgnoreCase(System.getProperty("com.jacob.autogc"));
"true".equalsIgnoreCase( System.getProperty( "com.jacob.autogc" ) );
/**
* A hash table where each element is another
@@ -59,38 +59,38 @@ public abstract class ROT {
* adds a new thread storage area to rot
* @return Map corresponding to the thread that this call was made in
*/
protected static Map addThread() {
protected synchronized static Map addThread() {
// should use the id here instead of the name because the name can be changed
String t_name = Thread.currentThread().getName();
if (rot.containsKey(t_name)){
if ( rot.containsKey( t_name ) ) {
// nothing to do
} else {
Map tab = null;
if (JacobObject.isDebugEnabled()){
JacobObject.debug("ROT: Automatic GC flag == "+ USE_AUTOMATIC_GARBAGE_COLLECTION
);}
if (!USE_AUTOMATIC_GARBAGE_COLLECTION){
if ( JacobObject.isDebugEnabled() ) {
JacobObject.debug( "ROT: Automatic GC flag == " + USE_AUTOMATIC_GARBAGE_COLLECTION );
}
if ( !USE_AUTOMATIC_GARBAGE_COLLECTION ) {
tab = new HashMap();
} else {
tab = new WeakHashMap();
}
rot.put(t_name,tab);
rot.put( t_name, tab );
}
return getThreadObjects(false);
return getThreadObjects( false );
}
/**
* returns the pool for this thread if it exists. can create a new
* one if you wish by passing in TRUE
* @param createIfDoesNotExist
* @return Map the collection that holds the objects created in the current thread
*/
protected static Map getThreadObjects(boolean createIfDoesNotExist) {
protected synchronized static Map getThreadObjects( boolean createIfDoesNotExist ) {
String t_name = Thread.currentThread().getName();
if (!rot.containsKey(t_name) && createIfDoesNotExist){
if ( !rot.containsKey( t_name ) && createIfDoesNotExist ) {
addThread();
}
return (Map)rot.get(t_name);
return (Map) rot.get( t_name );
}
/**
@@ -102,37 +102,37 @@ public abstract class ROT {
* This is called by COMThread in the tear down and provides a
* synchronous way of releasing memory
*/
protected static void clearObjects() {
Map tab = getThreadObjects(false);
if (JacobObject.isDebugEnabled()){
JacobObject.debug("ROT: "+rot.keySet().size()+" thread tables exist");
protected synchronized static void clearObjects() {
Map tab = getThreadObjects( false );
if ( JacobObject.isDebugEnabled() ) {
JacobObject.debug( "ROT: " + rot.keySet().size() + " thread tables exist" );
}
if (tab != null){
if (JacobObject.isDebugEnabled()){
JacobObject.debug("ROT: "+tab.keySet().size()+ " objects to clear in this thread " );
if ( tab != null ) {
if ( JacobObject.isDebugEnabled() ) {
JacobObject.debug( "ROT: " + tab.keySet().size() + " objects to clear in this thread " );
}
// walk the values
Iterator it;
if (USE_AUTOMATIC_GARBAGE_COLLECTION){
if ( USE_AUTOMATIC_GARBAGE_COLLECTION ) {
it = tab.keySet().iterator();
} else {
it = tab.values().iterator();
}
while (it.hasNext()) {
while ( it.hasNext() ) {
JacobObject o = (JacobObject) it.next();
if (o != null
if ( o != null
// can't use this cause creates a Variant if calling SafeAray
// and we get an exceptin modifying the collection while iterating
// && o.toString() != null
){
if (JacobObject.isDebugEnabled()){
if (o instanceof SafeArray){
) {
if ( JacobObject.isDebugEnabled() ) {
if ( o instanceof SafeArray ) {
// SafeArray create more objects when calling toString()
// which causes a concurrent modification exception in HashMap
JacobObject.debug("ROT: removing "+o.getClass().getName());
JacobObject.debug( "ROT: removing " + o.getClass().getName() );
} else {
// Variant toString() is probably always bad in here
JacobObject.debug("ROT: removing "+o.hashCode()+"->"+o.getClass().getName());
JacobObject.debug( "ROT: removing " + o.hashCode() + "->" + o.getClass().getName() );
}
}
o.safeRelease();
@@ -142,12 +142,14 @@ public abstract class ROT {
// empty the collection
tab.clear();
// remove the collection from rot
rot.remove(Thread.currentThread().getName());
if (JacobObject.isDebugEnabled()){
JacobObject.debug("ROT: thread table cleared and removed");
rot.remove( Thread.currentThread().getName() );
if ( JacobObject.isDebugEnabled() ) {
JacobObject.debug( "ROT: thread table cleared and removed" );
}
} else {
if (JacobObject.isDebugEnabled()){ JacobObject.debug("ROT: nothing to clear!");}
if ( JacobObject.isDebugEnabled() ) {
JacobObject.debug( "ROT: nothing to clear!" );
}
}
}
@@ -157,11 +159,11 @@ public abstract class ROT {
* @param o JacobObject we need key for
* @return some key compatabile with hashmaps
*/
protected static Object getMapKey(Map targetMap, JacobObject o){
if (targetMap instanceof WeakHashMap){
protected static Object getMapKey( Map targetMap, JacobObject o ) {
if ( targetMap instanceof WeakHashMap ) {
return o;
} else {
return new Integer(o.hashCode());
return new Integer( o.hashCode() );
}
}
@@ -171,8 +173,8 @@ public abstract class ROT {
* @param o JacobObject we need key for
* @return some compatabile with hashmaps (null for weak has map)
*/
protected static Object getMapValue(Map targetMap, JacobObject o){
if (targetMap instanceof WeakHashMap){
protected static Object getMapValue( Map targetMap, JacobObject o ) {
if ( targetMap instanceof WeakHashMap ) {
return null;
} else {
return o;
@@ -187,11 +189,11 @@ public abstract class ROT {
* This will remove an object from the ROT
* @param o
*/
protected static void removeObject(JacobObject o) {
protected synchronized static void removeObject( JacobObject o ) {
String t_name = Thread.currentThread().getName();
Map tab = (Map) rot.get(t_name);
if (tab != null) {
tab.remove(getMapKey(tab,o));
Map tab = (Map) rot.get( t_name );
if ( tab != null ) {
tab.remove( getMapKey( tab, o ) );
}
o.safeRelease();
}
@@ -200,20 +202,21 @@ public abstract class ROT {
* adds an object to the HashMap for the current thread
* @param o
*/
protected static void addObject(JacobObject o) {
Map tab = getThreadObjects(false);
if (tab == null) {
protected synchronized static void addObject( JacobObject o ) {
Map tab = getThreadObjects( false );
if ( tab == null ) {
// this thread has not been initialized as a COM thread
// so make it part of MTA for backwards compatibility
ComThread.InitMTA(false);
tab = getThreadObjects(true);
ComThread.InitMTA( false );
tab = getThreadObjects( true );
}
if (JacobObject.isDebugEnabled()){
if ( JacobObject.isDebugEnabled() ) {
JacobObject.debug(
"ROT: adding "+o+"->"+o.getClass().getName() +
" table size prior to addition:" +tab.size());}
if (tab != null) {
tab.put(getMapKey(tab,o),getMapValue(tab,o));
"ROT: adding " + o + "->" + o.getClass().getName() +
" table size prior to addition:" + tab.size() );
}
if ( tab != null ) {
tab.put( getMapKey( tab, o ), getMapValue( tab, o ) );
}
}
@@ -226,3 +229,4 @@ public abstract class ROT {
}
}