01: /*
02: * Copyright 2006 Sun Microsystems, Inc. All Rights Reserved.
03: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
04: *
05: * This code is free software; you can redistribute it and/or modify it
06: * under the terms of the GNU General Public License version 2 only, as
07: * published by the Free Software Foundation. Sun designates this
08: * particular file as subject to the "Classpath" exception as provided
09: * by Sun in the LICENSE file that accompanied this code.
10: *
11: * This code is distributed in the hope that it will be useful, but WITHOUT
12: * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13: * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14: * version 2 for more details (a copy is included in the LICENSE file that
15: * accompanied this code).
16: *
17: * You should have received a copy of the GNU General Public License version
18: * 2 along with this work; if not, write to the Free Software Foundation,
19: * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20: *
21: * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22: * CA 95054 USA or visit www.sun.com if you need additional information or
23: * have any questions.
24: */
25:
26: package com.sun.tools.internal.xjc.reader.gbind;
27:
28: import java.util.ArrayList;
29: import java.util.Iterator;
30: import java.util.List;
31:
32: /**
33: * Represents one strongly-connected component
34: * of the {@link Element} graph.
35: *
36: * @author Kohsuke Kawaguchi
37: */
38: public final class ConnectedComponent implements Iterable<Element> {
39: /**
40: * {@link Element}s that belong to this component.
41: */
42: private final List<Element> elements = new ArrayList<Element>();
43:
44: /*package*/boolean isRequired;
45:
46: /**
47: * Returns true iff this {@link ConnectedComponent}
48: * can match a substring whose length is greater than 1.
49: *
50: * <p>
51: * That means this property will become a collection property.
52: */
53: public final boolean isCollection() {
54: assert !elements.isEmpty();
55:
56: // a strongly connected component by definition has a cycle,
57: // so if its size is bigger than 1 there must be a cycle.
58: if (elements.size() > 1)
59: return true;
60:
61: // if size is 1, it might be still forming a self-cycle
62: Element n = elements.get(0);
63: return n.hasSelfLoop();
64: }
65:
66: /**
67: * Returns true iff this {@link ConnectedComponent}
68: * forms a cut set of a graph.
69: *
70: * <p>
71: * That means any valid element sequence must have at least
72: * one value for this property.
73: */
74: public final boolean isRequired() {
75: return isRequired;
76: }
77:
78: /*package*/void add(Element e) {
79: assert !elements.contains(e);
80: elements.add(e);
81: }
82:
83: public Iterator<Element> iterator() {
84: return elements.iterator();
85: }
86:
87: /**
88: * Just produces debug representation
89: */
90: public String toString() {
91: String s = elements.toString();
92: if (isRequired())
93: s += '!';
94: if (isCollection())
95: s += '*';
96: return s;
97: }
98: }
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