Created a list class that can be used to send around an ordered collection

of streamable objects. (They are manipulated all as one unit. For fine
grained distributed set management, use a DSet.)


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@396 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/presents/util/StreamableArrayList.java

@@ -0,0 +1,74 @@
+//
+// $Id: StreamableArrayList.java,v 1.1 2001/10/04 23:02:07 mdb Exp $
+
+package com.threerings.cocktail.cher.util;
+
+import java.io.IOException;
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+
+import java.util.ArrayList;
+import com.threerings.cocktail.cher.io.Streamable;
+
+/**
+ * Provides a means by which an ordered collection of streamable instances
+ * (all of the exact same class) can be delivered over the network. A
+ * streamable array list can be supplied anywhere that a distributed
+ * object value can be supplied, but bear in mind that once the list is
+ * created, it's elements cannot be changed without rebroadcasting the
+ * entire list. It is not like a {@link
+ * com.threerings.cocktail.cher.dobj.DSet} which allows individual
+ * elements to be added or removed.
+ */
+public class StreamableArrayList
+    extends ArrayList implements Streamable
+{
+    // documentation inherited
+    public void writeTo (DataOutputStream out)
+        throws IOException
+    {
+        int count = size();
+        out.writeInt(count);
+
+        // only write element info if we have elements
+        if (count > 0) {
+            Streamable first = (Streamable)get(0);
+            // write out the classname of our elements
+            out.writeUTF(first.getClass().getName());
+
+            // now write out our elements
+            for (int i = 0; i < count; i++) {
+                Streamable s = (Streamable)get(i);
+                s.writeTo(out);
+            }
+        }
+    }
+
+    // documentation inherited
+    public void readFrom (DataInputStream in)
+        throws IOException
+    {
+        // read in our element count
+        int count = in.readInt();
+
+        // only read in elements if we have some
+        if (count > 0) {
+            // read in the element class and load it up
+            String cname = in.readUTF();
+            try {
+                Class clazz = Class.forName(cname);
+
+                // now read in the elements
+                for (int i = 0; i < count; i++) {
+                    Streamable s = (Streamable)clazz.newInstance();
+                    s.readFrom(in);
+                    add(s);
+                }
+
+            } catch (Exception e) {
+                throw new IOException("Error reading streamable " +
+                                      "[class=" + cname + ", err=" + e + "]");
+            }
+        }
+    }
+}