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Added support for DObject transactions which are collections of events

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that are dispatched over the network at once and processed all at once.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@979 542714f4-19e9-0310-aa3c-eee0fc999fb1
This commit is contained in:
Michael Bayne
2002-02-09 07:50:37 +00:00
parent a1162ae85a
commit 1bca84927f
4 changed files with 389 additions and 85 deletions
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src/java/com/threerings/presents/dobj/DObject.java
+141 -36
View File
@@ -1,5 +1,5 @@
//
// $Id: DObject.java,v 1.38 2002/02/06 22:47:28 mdb Exp $
// $Id: DObject.java,v 1.39 2002/02/09 07:50:37 mdb Exp $
package com.threerings.presents.dobj;
@@ -130,8 +130,8 @@ public class DObject
// the last subscriber from our list; we also want to be sure
// that we're still active otherwise there's no need to notify
// our objmgr because we don't have one
if (--_scount == 0 && _mgr != null) {
_mgr.removedLastSubscriber(this);
if (--_scount == 0 && _omgr != null) {
_omgr.removedLastSubscriber(this);
}
}
}
@@ -226,8 +226,7 @@ public class DObject
public void releaseLock (String name)
{
// queue up a release lock event
ReleaseLockEvent event = new ReleaseLockEvent(_oid, name);
_mgr.postEvent(event);
postEvent(new ReleaseLockEvent(_oid, name));
}
/**
@@ -257,7 +256,7 @@ public class DObject
*/
public void destroy ()
{
_mgr.postEvent(new ObjectDestroyedEvent(_oid));
postEvent(new ObjectDestroyedEvent(_oid));
}
/**
@@ -410,7 +409,7 @@ public class DObject
*/
public boolean isActive ()
{
return _mgr != null;
return _omgr != null;
}
/**
@@ -421,9 +420,9 @@ public class DObject
*
* @see DObjectManager#createObject
*/
public void setManager (DObjectManager mgr)
public void setManager (DObjectManager omgr)
{
_mgr = mgr;
_omgr = omgr;
}
/**
@@ -448,16 +447,115 @@ public class DObject
return buf.append("]").toString();
}
/**
* Begins a transaction on this distributed object. In some
* situations, it is desirable to cause multiple changes to
* distributed object fields in one unified operation. Starting a
* transaction causes all subsequent field modifications to be stored
* in a single compound event which can then be committed, dispatching
* and applying all included events in a single group. Additionally,
* the events are dispatched over the network in a single unit which
* can significantly enhance network efficiency.
*
* <p> When the transaction is complete, the caller must call {@link
* #commitTransaction} or {@link CompoundEvent#commit} to commit the
* transaction and release all involved objects back to their normal
* non-transacting state. If the caller decides not to commit their
* transaction, they must call {@link #cancelTransaction} or {@link
* CompoundEvent#cancel} to cancel the transaction and release all
* involved objects. Failure to do so will cause the pooch to be
* totally screwed.
*
* <p> Note: like all other distributed object operations,
* transactions are not thread safe. It is expected that a single
* thread will handle all distributed object operations and that
* thread will begin and complete a transaction before giving up
* control to unknown code which might try to operate on the
* transacting distributed object (or objects).
*
* @return the compound event that encapsulates the transaction. This
* can be ignored if the transaction will be limited to this object,
* but if it is desired that other objects be involved in the
* transaction, the caller will need to pass the {@link CompoundEvent}
* returned by this method to a call to {@link #joinTransaction} on
* the other objects that are involved.
*/
public CompoundEvent startTransaction ()
{
if (_tevent != null) {
String errmsg = "Cannot start transaction on dobject that " +
"is already transacting [dobj=" + this + "]";
throw new IllegalStateException(errmsg);
}
_tevent = new CompoundEvent(_omgr);
_tevent.addObject(this);
return _tevent;
}
/**
* Causes this object to join the supplied transaction. See {@link
* #startTransaction} for more information on transactions.
*/
public void joinTransaction (CompoundEvent event)
{
if (_tevent != null) {
String errmsg = "Cannot join transaction while already " +
"transacting [dobj=" + this + "]";
throw new IllegalStateException(errmsg);
}
_tevent = event;
_tevent.addObject(this);
}
/**
* Commits the transaction in which this distributed object is
* involved.
*
* @see CompoundEvent#commit
*/
public void commitTransaction ()
{
if (_tevent == null) {
String errmsg = "Cannot commit: not involved in a transaction " +
"[dobj=" + this + "]";
throw new IllegalStateException(errmsg);
}
_tevent.commit();
}
/**
* Cancels the transaction in which this distributed object is
* involved.
*
* @see CompoundEvent#cancel
*/
public void cancelTransaction ()
{
if (_tevent == null) {
String errmsg = "Cannot cancel: not involved in a transaction " +
"[dobj=" + this + "]";
throw new IllegalStateException(errmsg);
}
_tevent.cancel();
}
/**
* Removes this object from participation in any transaction in which
* it might be taking part.
*/
protected void clearTransaction ()
{
_tevent = null;
}
/**
* Called by derived instances when an attribute setter method was
* called.
*/
protected void requestAttributeChange (String name, Object value)
{
// generate an attribute changed event
DEvent event = new AttributeChangedEvent(_oid, name, value);
// and dispatch it to our dobjmgr
_mgr.postEvent(event);
// dispatch an attribute changed event
postEvent(new AttributeChangedEvent(_oid, name, value));
}
/**
@@ -465,10 +563,8 @@ public class DObject
*/
protected void requestOidAdd (String name, int oid)
{
// generate an object added event
DEvent event = new ObjectAddedEvent(_oid, name, oid);
// and dispatch it to our dobjmgr
_mgr.postEvent(event);
// dispatch an object added event
postEvent(new ObjectAddedEvent(_oid, name, oid));
}
/**
@@ -476,10 +572,8 @@ public class DObject
*/
protected void requestOidRemove (String name, int oid)
{
// generate an object removed event
DEvent event = new ObjectRemovedEvent(_oid, name, oid);
// and dispatch it to our dobjmgr
_mgr.postEvent(event);
// dispatch an object removed event
postEvent(new ObjectRemovedEvent(_oid, name, oid));
}
/**
@@ -489,11 +583,9 @@ public class DObject
{
try {
DSet set = (DSet)getAttribute(name);
// generate an element added event
DEvent event = new ElementAddedEvent(
_oid, name, elem, !set.homogenous());
// and dispatch it to our dobjmgr
_mgr.postEvent(event);
// dispatch an element added event
postEvent(new ElementAddedEvent(
_oid, name, elem, !set.homogenous()));
} catch (ObjectAccessException oae) {
Log.warning("Unable to request elementAdd [name=" + name +
@@ -506,10 +598,8 @@ public class DObject
*/
protected void requestElementRemove (String name, Object key)
{
// generate an element removed event
DEvent event = new ElementRemovedEvent(_oid, name, key);
// and dispatch it to our dobjmgr
_mgr.postEvent(event);
// dispatch an element removed event
postEvent(new ElementRemovedEvent(_oid, name, key));
}
/**
@@ -519,11 +609,9 @@ public class DObject
{
try {
DSet set = (DSet)getAttribute(name);
// generate an element updated event
DEvent event = new ElementUpdatedEvent(
_oid, name, elem, !set.homogenous());
// and dispatch it to our dobjmgr
_mgr.postEvent(event);
// dispatch an element updated event
postEvent(new ElementUpdatedEvent(
_oid, name, elem, !set.homogenous()));
} catch (ObjectAccessException oae) {
Log.warning("Unable to request elementUpdate [name=" + name +
@@ -531,11 +619,24 @@ public class DObject
}
}
/**
* Posts the specified event either to our dobject manager or to the
* compound event for which we are currently transacting.
*/
protected void postEvent (TypedEvent event)
{
if (_tevent != null) {
_tevent.postEvent(event);
} else {
_omgr.postEvent(event);
}
}
/** Our object id. */
protected int _oid;
/** A reference to our object manager. */
protected DObjectManager _mgr;
protected DObjectManager _omgr;
/** A list of outstanding locks. */
protected Object[] _locks;
@@ -548,4 +649,8 @@ public class DObject
/** Our subscriber count. */
protected int _scount;
/** The compound event associated with our transaction, if we're
* currently in a transaction. */
protected CompoundEvent _tevent;
}