From 254ee6f47eebfc00462c10756a92066e82cc1a96 Mon Sep 17 00:00:00 2001
From: Andrew Branson <andrew@andrewbranson.net>
Date: Tue, 21 Jun 2011 15:46:02 +0200
Subject: Initial commit

---
 .../c2kernel/entity/proxy/MemberSubscription.java  | 121 +++++++++++++++++++++
 1 file changed, 121 insertions(+)
 create mode 100755 source/com/c2kernel/entity/proxy/MemberSubscription.java

(limited to 'source/com/c2kernel/entity/proxy/MemberSubscription.java')

diff --git a/source/com/c2kernel/entity/proxy/MemberSubscription.java b/source/com/c2kernel/entity/proxy/MemberSubscription.java
new file mode 100755
index 0000000..fdd3e96
--- /dev/null
+++ b/source/com/c2kernel/entity/proxy/MemberSubscription.java
@@ -0,0 +1,121 @@
+
+package com.c2kernel.entity.proxy;
+import java.lang.ref.WeakReference;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.StringTokenizer;
+
+import com.c2kernel.common.ObjectNotFoundException;
+import com.c2kernel.entity.C2KLocalObject;
+import com.c2kernel.utils.Logger;
+
+public class MemberSubscription implements Runnable {
+    EntityProxy subject;
+    String interest;
+    // keep the subscriber by weak reference, so it is not kept from the garbage collector if no longer used
+    WeakReference observerReference;
+    ArrayList contents = new ArrayList();
+    boolean preLoad;
+
+    public MemberSubscription(EntityProxy subject, String interest, 
+        EntityProxyObserver observer, boolean preLoad) {
+        setObserver(observer);
+        this.interest = interest;
+        this.subject = subject;
+        this.preLoad = preLoad;
+    }
+
+    public void run() {
+        Thread.currentThread().setName("Member Subscription: "+subject.getSystemKey()+":"+interest);
+        if (preLoad) loadChildren();
+    }
+    
+    private void loadChildren() {
+        C2KLocalObject newMember;
+        EntityProxyObserver observer = getObserver();
+        if (observer == null) return; //reaped 
+        try {
+            // fetch contents of path
+            String children = subject.queryData(interest+"/all");
+            StringTokenizer tok = new StringTokenizer(children, ",");
+            ArrayList newContents = new ArrayList();
+            while (tok.hasMoreTokens())
+                newContents.add(tok.nextToken());
+                
+            // look to see what's new
+            for (Iterator iter = newContents.iterator(); iter.hasNext();) {
+                String newChild = (String)iter.next();
+                
+                // load child object
+                try {
+                    newMember = subject.getObject(interest+"/"+newChild);
+                    contents.remove(newChild);
+                } catch (ObjectNotFoundException ex) {
+                    newMember = new MemberControl(MemberControl.ERROR, "Listed member "+newChild+" was not found.");
+                }
+                try {
+                    observer.add(newMember);
+                } catch (Throwable ex) {
+                    Logger.error("Error publishing member to "+observer);
+                    Logger.error(ex);
+                }
+            }
+            // report what's left in old contents as deleted
+            for (Iterator iter = contents.iterator(); iter.hasNext();) {
+                String oldChild = (String)iter.next();
+                observer.remove(interest+"/"+oldChild);
+            }
+            //replace contents arraylist
+            contents = newContents;
+            //report that we're done
+            observer.add(MemberControl.theEND);
+        } catch (Exception ex) {
+            observer.add(new MemberControl(MemberControl.ERROR, "Query on "+interest+" failed with "+ex));
+        }         
+    }
+    
+    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) {
+        EntityProxyObserver 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 {
+                    C2KLocalObject newMember = 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(EntityProxyObserver observer) {
+        observerReference = new WeakReference(observer);
+    }
+    
+    public EntityProxyObserver getObserver() {
+        EntityProxyObserver observer = (EntityProxyObserver)observerReference.get();
+        return observer;
+    }
+}
+
-- 
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