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First pass at a distributed lock system. Barbie says, "Concurrency is

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hard!"


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@4533 542714f4-19e9-0310-aa3c-eee0fc999fb1
This commit is contained in:
Andrzej Kapolka
2007-02-05 22:19:36 +00:00
parent dcedbbc7eb
commit 2f7c992320
3 changed files with 517 additions and 15 deletions
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src/java/com/threerings/presents/peer/data/Lock.java
+139
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@@ -0,0 +1,139 @@
//
// $Id$
package com.threerings.presents.peer.data;
import com.samskivert.util.ObjectUtil;
import com.threerings.io.SimpleStreamableObject;
import com.threerings.presents.dobj.DSet;
/**
* Describes a lock held by one of the peers.
*/
public class Lock extends SimpleStreamableObject
implements DSet.Entry
{
/**
* Identifies a locked resource by its type and type-specific identifier.
*/
public static class Name extends SimpleStreamableObject
implements Comparable
{
/**
* Creates a new lock name.
*
* @param type the type of resource. Only names with the same type will have their ids
* compared
* @param id the resource instance identifier. Can be <code>null</code> for resources with
* only one instance
*/
public Name (String type, Comparable id)
{
_type = type;
_id = id;
}
public Name ()
{
}
/**
* Returns the resource type.
*/
public String getType ()
{
return _type;
}
/**
* Returns the resource instance identifier.
*/
public Comparable getId ()
{
return _id;
}
// documentation inherited from interface Comparable
public int compareTo (Object other)
{
Name oname = (Name)other;
int v1 = _type.compareTo(oname._type);
if (v1 != 0 || _id == null) {
return v1;
}
@SuppressWarnings("unchecked") int v2 = _id.compareTo(oname._id);
return v2;
}
@Override // documentation inherited
public int hashCode ()
{
return _type.hashCode() + (_id == null ? 0 : _id.hashCode());
}
@Override // documentation inherited
public boolean equals (Object other)
{
Name oname = (Name)other;
return _type.equals(oname._type) &&
ObjectUtil.equals(_id, oname._id);
}
protected String _type;
protected Comparable _id;
}
/**
* Creates a newly acquired lock.
*/
public Lock (Name name, String owner)
{
_name = name;
_owner = owner;
}
/**
* No-arg constructor for deserialization.
*/
public Lock ()
{
}
/**
* Returns the name of the locked resource.
*/
public Name getName ()
{
return _name;
}
/**
* Returns the owner of the lock.
*/
public String getOwner ()
{
return _owner;
}
// documentation inherited from interface DSet.Entry
public Comparable getKey ()
{
return _name;
}
@Override // documentation inherited
public boolean equals (Object other)
{
Lock olock = (Lock)other;
return olock._name.equals(_name) &&
olock._owner.equals(_owner);
}
/** Identifies what is locked. */
protected Name _name;
/** The name of the node that owns the lock. */
protected String _owner;
}
src/java/com/threerings/presents/peer/data/NodeObject.java
+107 -9
View File
@@ -31,6 +31,23 @@ import com.threerings.presents.dobj.DSet;
*/
public class NodeObject extends DObject
{
// AUTO-GENERATED: FIELDS START
/** The field name of the <code>clients</code> field. */
public static final String CLIENTS = "clients";
/** The field name of the <code>locks</code> field. */
public static final String LOCKS = "locks";
/** The field name of the <code>acquiringLock</code> field. */
public static final String ACQUIRING_LOCK = "acquiringLock";
/** The field name of the <code>releasingLock</code> field. */
public static final String RELEASING_LOCK = "releasingLock";
/** The field name of the <code>cacheData</code> field. */
public static final String CACHE_DATA = "cacheData";
// AUTO-GENERATED: FIELDS END
/** Used for informing peers of changes to persistent data. */
public static class CacheData implements Streamable
{
@@ -49,20 +66,21 @@ public class NodeObject extends DObject
this.cache = cache;
this.data = data;
}
}
// AUTO-GENERATED: FIELDS START
/** The field name of the <code>clients</code> field. */
public static final String CLIENTS = "clients";
/** The field name of the <code>cacheData</code> field. */
public static final String CACHE_DATA = "cacheData";
// AUTO-GENERATED: FIELDS END
/** Contains information on all clients connected to this node. */
public DSet<ClientInfo> clients = new DSet<ClientInfo>();
/** This node's view of the peer lock set. A lock is acquired only when it has been added to
* all peers' sets, and is released only when it has been removed from all peers' sets. */
public DSet<Lock> locks = new DSet<Lock>();
/** Used to broadcast a node's desire to acquire a lock. */
public Lock.Name acquiringLock;
/** Used to broadcast a node's desire to release a lock. */
public Lock.Name releasingLock;
/** A field we use to broadcast changes to possible cached data. */
public CacheData cacheData;
@@ -115,6 +133,86 @@ public class NodeObject extends DObject
this.clients = clone;
}
/**
* Requests that the specified entry be added to the
* <code>locks</code> set. The set will not change until the event is
* actually propagated through the system.
*/
public void addToLocks (Lock elem)
{
requestEntryAdd(LOCKS, locks, elem);
}
/**
* Requests that the entry matching the supplied key be removed from
* the <code>locks</code> set. The set will not change until the
* event is actually propagated through the system.
*/
public void removeFromLocks (Comparable key)
{
requestEntryRemove(LOCKS, locks, key);
}
/**
* Requests that the specified entry be updated in the
* <code>locks</code> set. The set will not change until the event is
* actually propagated through the system.
*/
public void updateLocks (Lock elem)
{
requestEntryUpdate(LOCKS, locks, elem);
}
/**
* Requests that the <code>locks</code> field be set to the
* specified value. Generally one only adds, updates and removes
* entries of a distributed set, but certain situations call for a
* complete replacement of the set value. The local value will be
* updated immediately and an event will be propagated through the
* system to notify all listeners that the attribute did
* change. Proxied copies of this object (on clients) will apply the
* value change when they received the attribute changed notification.
*/
public void setLocks (DSet<com.threerings.presents.peer.data.Lock> value)
{
requestAttributeChange(LOCKS, value, this.locks);
@SuppressWarnings("unchecked") DSet<com.threerings.presents.peer.data.Lock> clone =
(value == null) ? null : value.typedClone();
this.locks = clone;
}
/**
* Requests that the <code>acquiringLock</code> field be set to the
* specified value. The local value will be updated immediately and an
* event will be propagated through the system to notify all listeners
* that the attribute did change. Proxied copies of this object (on
* clients) will apply the value change when they received the
* attribute changed notification.
*/
public void setAcquiringLock (Lock.Name value)
{
Lock.Name ovalue = this.acquiringLock;
requestAttributeChange(
ACQUIRING_LOCK, value, ovalue);
this.acquiringLock = value;
}
/**
* Requests that the <code>releasingLock</code> field be set to the
* specified value. The local value will be updated immediately and an
* event will be propagated through the system to notify all listeners
* that the attribute did change. Proxied copies of this object (on
* clients) will apply the value change when they received the
* attribute changed notification.
*/
public void setReleasingLock (Lock.Name value)
{
Lock.Name ovalue = this.releasingLock;
requestAttributeChange(
RELEASING_LOCK, value, ovalue);
this.releasingLock = value;
}
/**
* Requests that the <code>cacheData</code> field be set to the
* specified value. The local value will be updated immediately and an