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Implemented a Ray-proposed solution where we keep track of events that were

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(pre-applied and) posted before we received our object but processed (and hence
dispatched to us) after we received our object.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@4715 542714f4-19e9-0310-aa3c-eee0fc999fb1
This commit is contained in:
Michael Bayne
2007-05-18 03:37:14 +00:00
parent db3fe80e9d
commit 9bcca099ac
10 changed files with 268 additions and 230 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/java/com/threerings/presents/dobj/AttributeChangedEvent.java
+39 -44
View File
@@ -28,17 +28,17 @@ import java.util.HashMap;
import com.samskivert.util.StringUtil;
/**
* An attribute changed event is dispatched when a single attribute of a
* distributed object has changed. It can also be constructed to request
* an attribute change on an object and posted to the dobjmgr.
* An attribute changed event is dispatched when a single attribute of a distributed object has
* changed. It can also be constructed to request an attribute change on an object and posted to
* the dobjmgr.
*
* @see DObjectManager#postEvent
*/
public class AttributeChangedEvent extends NamedEvent
{
/**
* Constructs a blank instance of this event in preparation for
* unserialization from the network.
* Constructs a blank instance of this event in preparation for unserialization from the
* network.
*/
public AttributeChangedEvent ()
{
@@ -53,8 +53,7 @@ public class AttributeChangedEvent extends NamedEvent
}
/**
* Returns the value of the attribute prior to the application of this
* event.
* Returns the value of the attribute prior to the application of this event.
*/
public Object getOldValue ()
{
@@ -62,8 +61,8 @@ public class AttributeChangedEvent extends NamedEvent
}
/**
* Returns the new value of the attribute as a byte. This will fail
* if the attribute in question is not a byte.
* Returns the new value of the attribute as a byte. This will fail if the attribute in
* question is not a byte.
*/
public byte getByteValue ()
{
@@ -71,8 +70,8 @@ public class AttributeChangedEvent extends NamedEvent
}
/**
* Returns the new value of the attribute as a short. This will fail
* if the attribute in question is not a short.
* Returns the new value of the attribute as a short. This will fail if the attribute in
* question is not a short.
*/
public short getShortValue ()
{
@@ -80,8 +79,8 @@ public class AttributeChangedEvent extends NamedEvent
}
/**
* Returns the new value of the attribute as an int. This will fail if
* the attribute in question is not an int.
* Returns the new value of the attribute as an int. This will fail if the attribute in
* question is not an int.
*/
public int getIntValue ()
{
@@ -89,8 +88,8 @@ public class AttributeChangedEvent extends NamedEvent
}
/**
* Returns the new value of the attribute as a long. This will fail if
* the attribute in question is not a long.
* Returns the new value of the attribute as a long. This will fail if the attribute in
* question is not a long.
*/
public long getLongValue ()
{
@@ -98,8 +97,8 @@ public class AttributeChangedEvent extends NamedEvent
}
/**
* Returns the new value of the attribute as a float. This will fail
* if the attribute in question is not a float.
* Returns the new value of the attribute as a float. This will fail if the attribute in
* question is not a float.
*/
public float getFloatValue ()
{
@@ -107,37 +106,38 @@ public class AttributeChangedEvent extends NamedEvent
}
/**
* Returns the new value of the attribute as a double. This will fail
* if the attribute in question is not a double.
* Returns the new value of the attribute as a double. This will fail if the attribute in
* question is not a double.
*/
public double getDoubleValue ()
{
return ((Double)_value).doubleValue();
}
/**
* Applies this attribute change to the object.
*/
@Override // from DEvent
public boolean alreadyApplied ()
{
// if we have an old value, that means we're running on the master server and we have
// already applied this attribute change to the object
return (_oldValue != UNSET_OLD_VALUE);
}
@Override // from DEvent
public boolean applyToObject (DObject target)
throws ObjectAccessException
{
// if we have no old value, that means we're not running on the
// master server and we have not already applied this attribute
// change to the object, so we must grab the previous value and
// actually apply the attribute change
if (_oldValue == UNSET_OLD_VALUE) {
// if we're not already applied, grab the previous value and apply the attribute change
if (!alreadyApplied()) {
_oldValue = target.getAttribute(_name);
Object value = _value;
if (value != null) {
Class vclass = value.getClass();
if (vclass.isPrimitive()) {
// do nothing; we check this to avoid the more
// expensive isAssignableFrom check on primitives
// which are far and away the most common case
// do nothing; we check this to avoid the more expensive isAssignableFrom check
// on primitives which are far and away the most common case
} else if (vclass.isArray()) {
int length = Array.getLength(value);
Object clone = Array.newInstance(
vclass.getComponentType(), length);
Object clone = Array.newInstance(vclass.getComponentType(), length);
System.arraycopy(value, 0, clone, 0, length);
value = clone;
} else if (DSet.class.isAssignableFrom(vclass)) {
@@ -151,21 +151,16 @@ public class AttributeChangedEvent extends NamedEvent
}
/**
* Constructs a new attribute changed event on the specified target
* object with the supplied attribute name and value. <em>Do not
* construct these objects by hand.</em> Use {@link
* Constructs a new attribute changed event on the specified target object with the supplied
* attribute name and value. <em>Do not construct these objects by hand.</em> Use {@link
* DObject#changeAttribute} instead.
*
* @param targetOid the object id of the object whose attribute has
* changed.
* @param name the name of the attribute (data member) that has
* changed.
* @param value the new value of the attribute (in the case of
* primitive types, the reflection-defined object-alternative is
* used).
* @param targetOid the object id of the object whose attribute has changed.
* @param name the name of the attribute (data member) that has changed.
* @param value the new value of the attribute (in the case of primitive types, the
* reflection-defined object-alternative is used).
*/
protected AttributeChangedEvent (
int targetOid, String name, Object value, Object oldValue)
protected AttributeChangedEvent (int targetOid, String name, Object value, Object oldValue)
{
super(targetOid, name);
_value = value;
src/java/com/threerings/presents/dobj/DEvent.java
+14
View File
@@ -30,6 +30,10 @@ import com.threerings.io.Streamable;
*/
public abstract class DEvent implements Streamable
{
/** This event's "number". Every event dispatched by the server is numbered in monotonically
* increasing fashion when the event is posted to the event dispatch queue. */
public transient long eventId;
/**
* A zero argument constructor for unserialization from yon network.
*/
@@ -63,6 +67,16 @@ public abstract class DEvent implements Streamable
return false;
}
/**
* If this event applies itself immediately to the distributed object on the server and then
* NOOPs later when {@link #applyToObject} is called, it should return true from this method.
* If it will modify the object during its {@link #applyToObject} call, it should return false.
*/
public boolean alreadyApplied ()
{
return false;
}
/**
* Applies the attribute modifications represented by this event to the specified target
* object. This is called by the distributed object manager in the course of dispatching events
src/java/com/threerings/presents/dobj/ElementUpdatedEvent.java
+54 -56
View File
@@ -27,41 +27,37 @@ import java.lang.reflect.Field;
import com.samskivert.util.StringUtil;
/**
* An element updated event is dispatched when an element of an array
* field in a distributed object is updated. It can also be constructed to
* request the update of an entry and posted to the dobjmgr.
* An element updated event is dispatched when an element of an array field in a distributed object
* is updated. It can also be constructed to request the update of an entry and posted to the
* dobjmgr.
*
* @see DObjectManager#postEvent
*/
public class ElementUpdatedEvent extends NamedEvent
{
/**
* Constructs a new element updated event on the specified target
* object with the supplied attribute name, element and index.
* Constructs a new element updated event on the specified target object with the supplied
* attribute name, element and index.
*
* @param targetOid the object id of the object whose attribute has
* changed.
* @param name the name of the attribute (data member) for which an
* element has changed.
* @param value the new value of the element (in the case of primitive
* types, the reflection-defined object-alternative is used).
* @param oldValue the previous value of the element (in the case of
* primitive types, the reflection-defined object-alternative is
* used).
* @param targetOid the object id of the object whose attribute has changed.
* @param name the name of the attribute (data member) for which an element has changed.
* @param value the new value of the element (in the case of primitive types, the
* reflection-defined object-alternative is used).
* @param oldValue the previous value of the element (in the case of primitive types, the
* reflection-defined object-alternative is used).
* @param index the index in the array of the updated element.
*/
public ElementUpdatedEvent (
int targetOid, String name, Object value, Object oldValue, int index)
public ElementUpdatedEvent (int targetOid, String name, Object value, Object ovalue, int index)
{
super(targetOid, name);
_value = value;
_oldValue = oldValue;
_oldValue = ovalue;
_index = index;
}
/**
* Constructs a blank instance of this event in preparation for
* unserialization from the network.
* Constructs a blank instance of this event in preparation for unserialization from the
* network.
*/
public ElementUpdatedEvent ()
{
@@ -76,8 +72,7 @@ public class ElementUpdatedEvent extends NamedEvent
}
/**
* Returns the value of the element prior to the application of this
* event.
* Returns the value of the element prior to the application of this event.
*/
public Object getOldValue ()
{
@@ -93,8 +88,8 @@ public class ElementUpdatedEvent extends NamedEvent
}
/**
* Returns the new value of the element as a short. This will fail if
* the element in question is not a short.
* Returns the new value of the element as a short. This will fail if the element in question
* is not a short.
*/
public short getShortValue ()
{
@@ -102,8 +97,8 @@ public class ElementUpdatedEvent extends NamedEvent
}
/**
* Returns the new value of the element as an int. This will fail if
* the element in question is not an int.
* Returns the new value of the element as an int. This will fail if the element in question is
* not an int.
*/
public int getIntValue ()
{
@@ -111,8 +106,8 @@ public class ElementUpdatedEvent extends NamedEvent
}
/**
* Returns the new value of the element as a long. This will fail if
* the element in question is not a long.
* Returns the new value of the element as a long. This will fail if the element in question is
* not a long.
*/
public long getLongValue ()
{
@@ -120,8 +115,8 @@ public class ElementUpdatedEvent extends NamedEvent
}
/**
* Returns the new value of the element as a float. This will fail if
* the element in question is not a float.
* Returns the new value of the element as a float. This will fail if the element in question
* is not a float.
*/
public float getFloatValue ()
{
@@ -129,47 +124,50 @@ public class ElementUpdatedEvent extends NamedEvent
}
/**
* Returns the new value of the element as a double. This will fail if
* the element in question is not a double.
* Returns the new value of the element as a double. This will fail if the element in question
* is not a double.
*/
public double getDoubleValue ()
{
return ((Double)_value).doubleValue();
}
/**
* Applies this element update to the object.
*/
@Override // from DEvent
public boolean alreadyApplied ()
{
return (_oldValue == UNSET_OLD_VALUE);
}
@Override // from DEvent
public boolean applyToObject (DObject target)
throws ObjectAccessException
{
try {
// fetch the array field from the object
Field field = target.getClass().getField(_name);
Class ftype = field.getType();
if (!alreadyApplied()) {
try {
// fetch the array field from the object
Field field = target.getClass().getField(_name);
Class ftype = field.getType();
// sanity check
if (!ftype.isArray()) {
String msg = "Requested to set element on non-array field.";
throw new Exception(msg);
}
// sanity check
if (!ftype.isArray()) {
String msg = "Requested to set element on non-array field.";
throw new Exception(msg);
}
// grab the previous value to provide to interested parties
if (_oldValue == UNSET_OLD_VALUE) {
// grab the previous value to provide to interested parties
_oldValue = Array.get(field.get(target), _index);
// we don't do any magical expansion or any funny business; the array should be big
// enough to contain the value being updated or we'll throw an
// ArrayIndexOutOfBoundsException
Array.set(field.get(target), _index, _value);
} catch (Exception e) {
String msg = "Error updating element [field=" + _name + ", index=" + _index + "]";
throw new ObjectAccessException(msg, e);
}
// we don't do any magical expansion or any funny business;
// the array should be big enough to contain the value being
// updated or we'll throw an ArrayIndexOutOfBoundsException
Array.set(field.get(target), _index, _value);
return true;
} catch (Exception e) {
String msg = "Error updating element [field=" + _name +
", index=" + _index + "]";
throw new ObjectAccessException(msg, e);
}
return true;
}
// documentation inherited
src/java/com/threerings/presents/dobj/EntryAddedEvent.java
+8 -28
View File
@@ -73,39 +73,19 @@ public class EntryAddedEvent<T extends DSet.Entry> extends NamedEvent
return _entry;
}
/**
* Applies this event to the object.
*/
@Override // from DEvent
public boolean alreadyApplied ()
{
return _alreadyApplied;
}
@Override // from DEvent
public boolean applyToObject (DObject target)
throws ObjectAccessException
{
if (!_alreadyApplied) {
if (!target.getSet(_name).add(_entry)) {
// If this entry is already in the set, then don't notify our listeners of the
// event add, because nothing was actually added; the DSet will have already
// complained; this happens occasionally due to a race condition between client
// object subscription and set addition, for example, the follow sequence of events
// can take place:
//
// 1. SUBSCRIBE arrives from client, AccessObjectEvent posted;
//
// 2. addToSet() called on server, value immediately added to set and
// EntryAddedEvent is posted;
//
// 3. AccessObjectEvent processed; client is added to proxy subscriber list,
// DObject serialized and sent to client; client receives object which already has
// the entry in the set;
//
// 4. EntryAddedEvent processed, client is a subscriber so it is forwarded along;
// when it arrives at the client, we find ourselves in this situation.
//
// Fixing this would require either a) giving up immediate adding to the DSet when
// an event is posted, but we add/update immediately because it makes our lives
// *vastly* simpler in a thousand other cases, or b) doing some magic in the DSet
// where the server "sees" the new entry added, but if the DSet is serialized
// before the EntryAddedEvent comes through to "commit" that entry it is not
// included. This is probably a good idea and maybe we'll do it sometime.
return false;
return false; // DSet will have already complained
}
}
return true;
src/java/com/threerings/presents/dobj/EntryRemovedEvent.java
+8 -4
View File
@@ -72,13 +72,17 @@ public class EntryRemovedEvent<T extends DSet.Entry> extends NamedEvent
return _oldEntry;
}
/**
* Applies this event to the object.
*/
@Override // from DEvent
public boolean alreadyApplied ()
{
return (_oldEntry != UNSET_OLD_ENTRY);
}
@Override // from DEvent
public boolean applyToObject (DObject target)
throws ObjectAccessException
{
if (_oldEntry == UNSET_OLD_ENTRY) {
if (!alreadyApplied()) {
DSet<T> set = target.getSet(_name);
// remove, fetch the previous value for interested callers
_oldEntry = set.removeKey(_key);
src/java/com/threerings/presents/dobj/EntryUpdatedEvent.java
+8 -4
View File
@@ -73,14 +73,18 @@ public class EntryUpdatedEvent<T extends DSet.Entry> extends NamedEvent
return _oldEntry;
}
/**
* Applies this event to the object.
*/
@Override // from DEvent
public boolean alreadyApplied ()
{
return (_oldEntry != UNSET_OLD_ENTRY);
}
@Override // from DEvent
public boolean applyToObject (DObject target)
throws ObjectAccessException
{
// only apply the change if we haven't already
if (_oldEntry == UNSET_OLD_ENTRY) {
if (!alreadyApplied()) {
DSet<T> set = target.getSet(_name);
// fetch the previous value for interested callers
_oldEntry = set.update(_entry);
src/java/com/threerings/presents/dobj/ProxySubscriber.java
+3 -4
View File
@@ -22,10 +22,9 @@
package com.threerings.presents.dobj;
/**
* Defines a special kind of subscriber that proxies events for a
* subordinate distributed object manager. All events dispatched on
* objects with which this subscriber is registered are passed along to
* the subscriber for delivery to its subordinate manager.
* Defines a special kind of subscriber that proxies events for a subordinate distributed object
* manager. All events dispatched on objects with which this subscriber is registered are passed
* along to the subscriber for delivery to its subordinate manager.
*
* @see DObject#addListener
*/