1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
|
/**
* This file is part of the CRISTAL-iSE kernel.
* Copyright (c) 2001-2014 The CRISTAL Consortium. All rights reserved.
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 3 of the License, or (at
* your option) any later version.
*
* This library is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; with out even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*
* http://www.fsf.org/licensing/licenses/lgpl.html
*/
package org.cristalise.kernel.entity.proxy;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.StringTokenizer;
import org.cristalise.kernel.common.ObjectNotFoundException;
import org.cristalise.kernel.entity.C2KLocalObject;
import org.cristalise.kernel.utils.Logger;
public class MemberSubscription<C extends C2KLocalObject> implements Runnable {
public static final String ERROR = "Error";
public static final String END = "theEND";
ItemProxy subject;
String interest;
// keep the subscriber by weak reference, so it is not kept from the garbage collector if no longer used
WeakReference<ProxyObserver<C>> observerReference;
ArrayList<String> contents = new ArrayList<String>();
boolean preLoad;
public MemberSubscription(ProxyObserver<C> observer, String interest, boolean preLoad) {
setObserver(observer);
this.interest = interest;
this.preLoad = preLoad;
}
@Override
public void run() {
Thread.currentThread().setName("Member Subscription: "+subject.getPath()+":"+interest);
if (preLoad) loadChildren();
}
private void loadChildren() {
C newMember;
ProxyObserver<C> observer = getObserver();
if (observer == null) return; //reaped
try {
// fetch contents of path
String children = subject.queryData(interest+"/all");
StringTokenizer tok = new StringTokenizer(children, ",");
ArrayList<String> newContents = new ArrayList<String>();
while (tok.hasMoreTokens())
newContents.add(tok.nextToken());
// look to see what's new
for (String newChild: newContents) {
// load child object
try {
newMember = (C)subject.getObject(interest+"/"+newChild);
contents.remove(newChild);
observer.add(newMember);
} catch (ObjectNotFoundException ex) {
observer.control(ERROR, "Listed member "+newChild+" was not found.");
} catch (ClassCastException ex) {
Logger.error(ex);
observer.control(ERROR, "Listed member "+newChild+" was the wrong type.");
}
}
// report what's left in old contents as deleted
for (String oldChild: contents) {
observer.remove(interest+"/"+oldChild);
}
//replace contents arraylist
contents = newContents;
//report that we're done
observer.control(END, null);
} catch (Exception ex) {
observer.control(ERROR, "Query on "+interest+" failed with "+ex.getMessage());
}
}
public boolean isRelevant(String path) {
Logger.msg(7, "Checking relevance of "+path+" to "+interest);
return (path.startsWith(interest));
}
public void update(String path, boolean deleted) {
ProxyObserver<C> observer = getObserver();
if (observer == null) return; //reaped
Logger.msg(7, "Processing proxy message path "+path +" for "+observer+". Interest: "+interest+" Was Deleted:"+deleted);
if (!path.startsWith(interest)) // doesn't concern us
return;
if (path.equals(interest)) // refresh contents
loadChildren();
else {
String name = path.substring(interest.length());
if (deleted) {
Logger.msg(4, "Removing "+path);
contents.remove(name);
observer.remove(name);
}
else {
try {
C newMember = (C)subject.getObject(path);
Logger.msg(4, "Adding "+path);
contents.add(name);
observer.add(newMember);
} catch (ObjectNotFoundException e) {
Logger.error("Member Subscription: could not load "+path);
Logger.error(e);
}
}
}
}
public void setObserver(ProxyObserver<C> observer) {
observerReference = new WeakReference<ProxyObserver<C>>(observer);
}
public void setSubject(ItemProxy subject) {
this.subject = subject;
}
public ProxyObserver<C> getObserver() {
return observerReference.get();
}
}
|
