1 files changed, 118 insertions, 0 deletions
diff --git a/src/main/java/com/c2kernel/entity/proxy/MemberSubscription.java b/src/main/java/com/c2kernel/entity/proxy/MemberSubscription.java
new file mode 100644
index 0000000..157297f
--- /dev/null
+++ b/src/main/java/com/c2kernel/entity/proxy/MemberSubscription.java
@@ -0,0 +1,118 @@
+
+package com.c2kernel.entity.proxy;
+import java.lang.ref.WeakReference;
+import java.util.ArrayList;
+import java.util.StringTokenizer;
+
+import com.c2kernel.common.ObjectNotFoundException;
+import com.c2kernel.entity.C2KLocalObject;
+import com.c2kernel.utils.Logger;
+
+public class MemberSubscription<C extends C2KLocalObject> implements Runnable {
+	public static final String ERROR = "Error";
+	public static final String END = "theEND";
+	
+    EntityProxy subject;
+    String interest;
+    // keep the subscriber by weak reference, so it is not kept from the garbage collector if no longer used
+    WeakReference<EntityProxyObserver<C>> observerReference;
+    ArrayList<String> contents = new ArrayList<String>();
+    boolean preLoad;
+
+    public MemberSubscription(EntityProxyObserver<C> observer, String interest, boolean preLoad) {
+        setObserver(observer);
+        this.interest = interest;
+        this.preLoad = preLoad;
+    }
+
+    @Override
+	public void run() {
+        Thread.currentThread().setName("Member Subscription: "+subject.getSystemKey()+":"+interest);
+        if (preLoad) loadChildren();
+    }
+
+    private void loadChildren() {
+        C newMember;
+        EntityProxyObserver<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.");
+                }
+            }
+            // 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);
+        }
+    }
+
+    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<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(EntityProxyObserver<C> observer) {
+        observerReference = new WeakReference<EntityProxyObserver<C>>(observer);
+    }
+    
+    public void setSubject(EntityProxy subject) {
+    	this.subject = subject;
+    }
+
+    public EntityProxyObserver<C> getObserver() {
+        return observerReference.get();
+    }
+}
+