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 public Topology toAtom() { return this; }
17 /** equality is based on the underlying <tt>Topology</tt> */
18 public int hashCode() { return top().hashCode(); }
20 /** equality is based on the underlying <tt>Topology</tt> */
21 public boolean equals(Object o) { return o != null && o instanceof Atom && ((Atom)o).top().equals(top()); }
23 /** declared abstract to force subclasses to override it in a useful manner */
24 public abstract String toString();
26 // Topology Thunks //////////////////////////////////////////////////////////////////////////////
28 public Topology<T> unwrap() { return top().unwrap(); }
29 public Topology<T> empty() { return top().empty(); }
30 public boolean contains(T v) { return top().contains(v); }
31 public Topology<T> intersect(Topology<T> t) { return top().intersect(t); }
32 public Topology<T> minus(Topology<T> t) { return top().minus(t); }
33 public Topology<T> union(Topology<T> t) { return top().union(t); }
34 public Topology<T> complement() { return top().complement(); }
35 public boolean disjoint(Topology<T> t) { return top().disjoint(t); }
36 public boolean containsAll(Topology<T> t) { return top().containsAll(t); }
38 // Subclasses //////////////////////////////////////////////////////////////////////////////
40 public static class Infer<T extends Token> extends Atom<T> {
41 private final Element e;
42 public Infer(Element e) { this.e = e; }
43 public Topology<T> top() { return (Topology<T>)e.toAtom(); }
44 public String toString() { return e.toString(); }
47 public static class Invert<T extends Token> extends Atom<T> {
48 private final Atom<T> a;
49 public Invert(Atom<T> a) { this.a = a; }
50 public Topology<T> top() { return ((Topology<T>)a.top()).complement(); }
51 public String toString() { return "~"+a; }