1 package edu.berkeley.sbp;
4 import java.lang.reflect.*;
5 import java.lang.ref.*;
6 import edu.berkeley.sbp.util.*;
7 import edu.berkeley.sbp.*;
8 import edu.berkeley.sbp.*;
10 /** an element which matches exactly one input token */
11 public abstract class Atom<T extends Token> extends Element implements Topology<T> {
13 protected abstract Topology<T> top();
15 void reachable(HashSet<Sequence.Position> h) { /* do-nothing */ }
17 public Topology toAtom() { return dup(); }
19 /** equality is based on the underlying <tt>Topology</tt> */
20 public int hashCode() { return top().hashCode(); }
22 /** equality is based on the underlying <tt>Topology</tt> */
23 public boolean equals(Object o) { return o != null && o instanceof Atom && ((Atom)o).top().equals(top()); }
25 /** declared abstract to force subclasses to override it in a useful manner */
26 public abstract String toString();
28 // Topology Thunks //////////////////////////////////////////////////////////////////////////////
30 public void add(Topology<T> t) { top().add(t); }
31 public void add(T t) { top().add(t); }
32 public void remove(Topology<T> t) { top().remove(t); }
33 public void remove(T t) { top().remove(t); }
34 public Topology<T> dup() { return top().dup(); }
35 public boolean contains(T v) { return top().contains(v); }
36 public Topology<T> fresh() { return top().fresh(); }
37 public Topology<T> intersect(Topology<T> t) { return top().intersect(t); }
38 public Topology<T> minus(Topology<T> t) { return top().minus(t); }
39 public Topology<T> union(Topology<T> t) { return top().union(t); }
40 public Topology<T> complement() { return top().complement(); }
41 public boolean disjoint(Topology<T> t) { return top().disjoint(t); }
42 public boolean containsAll(Topology<T> t) { return top().containsAll(t); }
44 // Subclasses //////////////////////////////////////////////////////////////////////////////
46 public static class Infer<T extends Token> extends Atom<T> {
47 private final Element e;
48 public Infer(Element e) { this.e = e; }
49 public Topology<T> top() { return (Topology<T>)e.toAtom(); }
50 public String toString() { return e.toString(); }
53 public static class Invert<T extends Token> extends Atom<T> {
54 private final Atom<T> a;
55 public Invert(Atom<T> a) { this.a = a; }
56 public Topology<T> top() { return ((Topology<T>)a.top()).complement(); }
57 public String toString() { return "~"+a; }