X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FAtom.java;h=a9e89814225a8de049de9e2f062ddad58f09f13b;hp=0989bc0d717b39da90bc390d1bd7ebc4c1e169d7;hb=HEAD;hpb=173e1696d10a91db6f5a919dbb2b2ed2c6e2a227

diff --git a/src/edu/berkeley/sbp/Atom.java b/src/edu/berkeley/sbp/Atom.java
index 0989bc0..a9e8981 100644
--- a/src/edu/berkeley/sbp/Atom.java
+++ b/src/edu/berkeley/sbp/Atom.java
@@ -1,18 +1,29 @@
+// (C) 2006-2007 all rights reserved; see LICENSE file for BSD-style license
+
 package edu.berkeley.sbp;
-import java.io.*;
-import java.util.*;
-import java.lang.reflect.*;
-import java.lang.ref.*;
 import edu.berkeley.sbp.util.*;
-import edu.berkeley.sbp.*;
-import edu.berkeley.sbp.*;
 
-/** <font color=green>an element which matches exactly one input token</font> */
-public abstract class Atom<T> extends Element implements Topology<Atom<T>> {
+/**
+ *  <font color=green>
+ *  an element which matches some set of one-token-long input strings
+ *  </font>.
+ *
+ *  <p>
+ *  This class is a topology over itself (yes, this is impredicative).
+ *  This means that you can call Atom.union(Atom) and get back an Atom.
+ *  If you are interested in the topology of <i>tokens</i> which this
+ *  Atom can match, use the <tt>getTokenTopology()</tt> method.
+ *  </p>
+ */
+public abstract class Atom<Token>
+    extends Element
+    implements Topology<Atom<Token>> {
+
+    /** the set (topology) of tokens that can match this element */
+    public abstract Topology<Token>  getTokenTopology();
 
-    public  abstract Topology<T>  underlying();
-    public    abstract String       toString();
-    public             StringBuffer toString(StringBuffer sb) { sb.append(this); return sb; }
+    StringBuffer toString(StringBuffer sb) { sb.append(this); return sb; }
 
 }
 
+